Method and device for transmitting radio power

0001The present invention relates to a method and device for transmitting wireless power, and more particularly to a method and device for transmitting wireless power to a plurality of wireless power receivers.

0002Recently, wireless charging or non-contact charging technology has been developed and is widely used in various electronic devices such as wireless electric toothbrushes or wireless turning razors.

0003Such wireless charging technology is based on wireless power transfer, and the battery of an electronic device such as a mobile phone allows the user to turn the mobile phone into a charging pad, for example, without connecting a separate charging connector to the mobile phone. As long as you leave it, it can be charged automatically.

0004Wireless charging technology can be broadly divided into a coil-based electromagnetic induction method, a resonance method, and a radio frequency (RF) / MicroWave Radiation method that transmits electric energy by converting it into microwaves. ..

0005The method using electromagnetic induction has been frequently used, but recently, experiments using the RF / microwave radiation method have been successful. Therefore, in the future, it is expected that many kinds of electronic products will be charged wirelessly.

0006Power transmission based on electromagnetic induction transmits power between the primary coil and the secondary coil. For example, an induced current is generated when the magnet is moved around the coil. Using such a principle, the transmitter generates a magnetic field, and in the receiver, a change in the magnetic field induces an electric current, which produces energy. This power transmission method has excellent energy transmission efficiency.

0007In contrast to the resonance scheme, power can be transferred wirelessly using Coupled Mode Theory, even if the electrical device is located a few meters away from the charging device. The resonance method is based on the physics concept that when a tuning fork sounds, wine glasses located nearby can sound at the same frequency.

<p num="0008"> However, the resonance method resonates an electromagnetic wave containing electrical energy instead of resonating the voice. The resonated electrical energy is directly transmitted only to devices having the same resonance frequency, and the unused portion is reabsorbed as an electromagnetic field instead of being diffused into the air. Therefore, unlike other electromagnetic waves, the resonated electrical energy must not affect surrounding devices and the body.</p><p num="0009"> Recently, a lot of attention and research on wireless charging methods have been actively advanced, but the ranking of wireless charging, the search for wireless power transmitters and receivers, the selection of the communication frequency between wireless power transmitters and wireless power receivers, No standards have been proposed for adjusting wireless power, selecting matching circuits, and distributing communication time to each wireless power receiver in a single charging cycle. In particular, standards are required for wireless power transmitters that determine the addition of wireless power receivers to wireless power networks managed by wireless power transmitters and the removal of wireless power receivers from wireless power networks.</p><p num="0010"> An object of the present invention is to address at least the above-mentioned problems and / or inconveniences and to provide at least the following conveniences. That is, an object of the present invention is to provide a standard for the overall operation of a wireless power transmitter / receiver.</p><p num="0011"> Another object of the present invention provides a wireless power transmitter and method for determining the addition of a wireless power receiver to a wireless power network managed by the wireless power transmitter and the removal of the wireless power receiver from the wireless power network. There is.</p>

<p num="0012"> In order to achieve the above object, according to one aspect of the present invention, there is provided a method of transmitting wireless power in a wireless power network managed by a wireless power transmitter. In the above method, a step of transmitting the first charge power to the first wireless power receiver, a step of detecting the second wireless power receiver, and forming a communication network with the second wireless power receiver are formed. It includes a step, a step of joining the second wireless power receiver to the wireless power network, and a step of transmitting the second charging power to the second wireless power receiver.</p><p num="0013"> According to another aspect of the invention, there is provided a wireless power transmitter that transmits wireless power in a wireless power network. The wireless power transmitter includes a power transmission unit that transmits the first charging power to the first wireless power receiver, a control unit that detects the second wireless power receiver, and the second wireless power. The control unit includes the receiver and the communication unit forming the communication network, and the control unit subscribes the second wireless power receiver to the wireless power network and supplies the second charging power to the second wireless power receiver. The power transmission unit is controlled so as to transmit to.</p><p num="0014"> According to still another aspect of the present invention, there is provided a method of transmitting wireless power to a first wireless power receiver and a second wireless power receiver of a wireless power network managed by the wireless power transmitter. In the above method, a step of transmitting a command signal for instructing the power information report of the first wireless power receiver to the wireless power transmitter and a report signal corresponding to the command signal are transmitted to the wireless power transmitter in a predetermined period. The report signal is sent from the first wireless power receiver during the step of determining whether or not to receive from the wireless power receiver of 1 and the time corresponding to the predetermined number of times in the predetermined period. This includes a step of determining that the first wireless power receiver has been removed from the wireless power network when reception is not possible.</p><p num="0015"> According to still another aspect of the present invention, there is provided a wireless power transmitter that transmits wireless power to a first wireless power receiver and a second wireless power receiver in a wireless power network managed by the wireless power transmitter. To. The wireless power transmitter has a communication unit that transmits a command signal for instructing the power information report of the first wireless power receiver to the first wireless power receiver in a predetermined period, and the command signal. It is determined whether or not the corresponding report signal is received from the first radio power receiver, and the first radio power receiver during the time corresponding to the predetermined number of times in the predetermined period. Includes a control unit that determines that the first radio power receiver has been removed from the radio power network when the report signal cannot be received from.</p>

<p num="0016"> In the embodiment of the present invention, wireless charging can be reliably performed based on the Zigbee method and the BLE method.</p><p num="0017"> Various embodiments of the present invention include a wireless power transfer process that determines whether to subscribe a wireless power receiver to a wireless power network or remove the wireless power receiver from the wireless power network by preventing power waste. provide.</p><p num="0018"> The objectives, properties, and advantages of one embodiment of the invention should be further clarified by the following description, along with the accompanying drawings. In the above drawings, it should be found that the same drawing reference reference numerals mean the same elements, properties, and structures.</p>

0019<figref num="1">It is a figure which shows the wireless charging system by one Embodiment of this invention.</figref><figref num="2A">It is a block diagram which shows the structure of the wireless power transmitter and the wireless power receiver by one Embodiment of this invention.</figref><figref num="2B">It is a block diagram which shows the structure of the wireless power receiver by one Embodiment of this invention.</figref><figref num="3">It is a flowchart which shows the wireless power transmission / reception method by one Embodiment of this invention.</figref><figref num="4A">It is a circuit diagram which shows the wireless power transmitter by one Embodiment of this invention.</figref><figref num="4B">It is a graph which shows the current and voltage measured with the passage of time by the wireless power transmitter by one Embodiment of this invention, respectively.</figref><figref num="4C">It is a graph which shows the current and voltage measured with the passage of time by the wireless power transmitter by one Embodiment of this invention, respectively.</figref><figref num="4D">It is a graph which shows the temperature measured with the lapse of time at one point of the wireless power transmitter by one Embodiment of this invention.</figref><figref num="4E">It is a graph which shows the phase at one point of the wireless power transmitter by one Embodiment of this invention.</figref><figref num="5">It is a timing diagram which shows the load detection and signal transmission of the wireless power transmitter by one Embodiment of this invention.</figref><figref num="6A">FIG. 5 is a timing diagram showing a power supply operation between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.</figref><figref num="6B">FIG. 5 is a timing diagram showing a power supply operation between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.</figref><figref num="7">It is a flowchart which shows the wireless power transmission method by one Embodiment of this invention.</figref><figref num="8A">It is a timing diagram which shows the operation that the wireless power receiver according to one Embodiment of this invention fails to join the wireless power network managed by a wireless power transmitter.</figref><figref num="8B">It is a timing diagram which shows the operation that the wireless power receiver according to one Embodiment of this invention fails to join the wireless power network managed by a wireless power transmitter.</figref><figref num="9A">It is a timing diagram which shows the operation which determines the removal of the wireless power receiver by one Embodiment of this invention.</figref><figref num="9B">It is a timing diagram which shows the operation which determines the removal of the wireless power receiver by one Embodiment of this invention.</figref><figref num="10">It is a flowchart which shows the method for joining the wireless power receiver and transmitting the charge power in the wireless power transmitter by one Embodiment of this invention.</figref><figref num="11A">FIG. 5 is a timing diagram showing a power supply operation between a wireless power transmitter and two wireless power receivers according to an embodiment of the present invention.</figref><figref num="11B">FIG. 5 is a timing diagram showing a power supply operation between a wireless power transmitter and two wireless power receivers according to an embodiment of the present invention.</figref><figref num="12">It is a figure which shows the timing division of the wireless power transmitter by one Embodiment of this invention.</figref><figref num="13">It is a flowchart which shows the method of the wireless power transmitter by one Embodiment of this invention.</figref><figref num="14">It is a conceptual diagram which shows the change of the allocation time by removing the wireless power receiver from the wireless power network managed by the wireless power transmitter by one Embodiment of this invention.</figref><figref num="15">It is a figure which shows the apparatus control table which manages the wireless power receiver in the wireless power transmitter by one Embodiment of this invention.</figref><figref num="16A">FIG. 5 is a timing diagram showing an operation of removing one of two wireless power receivers from a wireless power network managed by a wireless power transmitter according to an embodiment of the present invention.</figref><figref num="16B">FIG. 5 is a timing diagram showing an operation of removing one of two wireless power receivers from a wireless power network managed by a wireless power transmitter according to an embodiment of the present invention.</figref><figref num="17A">FIG. 5 is a timing diagram showing a communication signal between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.</figref><figref num="17B">FIG. 5 is a timing diagram showing a communication signal between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.</figref><figref num="18">It is explanatory drawing which shows the apparatus control table by one Embodiment of this invention.</figref>

0020Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, it is provided to assist in a comprehensive understanding of the embodiments of the present invention as defined within the scope of the claims and equivalents thereof, and to assist in this understanding. It contains various specific details, but is only one embodiment. Therefore, it is clear to those who have ordinary knowledge in the art that various modifications and modifications of the embodiments described herein are possible without departing from the scope and gist of the present invention. Further, from the viewpoint of clarity and conciseness, specific description of functions and configurations well known to those skilled in the art will be omitted.

0021FIG. 1 is a diagram showing a wireless charging system according to an embodiment of the present invention. Referring to FIG. 1, the wireless charging system includes a wireless power transmitter 100 and wireless power receivers 110-1, 110-2, and 110-n. The wireless power transmitter 100 wirelessly transmits the powers 1-1, 1-2, and 1-n to the wireless power receivers 110-1, 110-2, and 110-n, respectively. More specifically, the wireless power transmitter 100 wirelessly transmits power 1-1, 1-2, and 1-n only to the authenticated wireless power receiver by performing a predetermined authentication procedure.

0022The wireless power transmitter 100 forms an electrical connection with the wireless power receivers 110-1, 110-2, and 110-n. For example, the wireless power transmitter 100 transmits wireless power in the form of electromagnetic waves to the wireless power receivers 110-1, 110-2, and 110-n.

0023The wireless power transmitter 100 also performs bidirectional communication with the wireless power receivers 110-1, 110-2, and 110-n. Here, the wireless power transmitter 100 and the wireless power receivers 110-1, 110-2, and 110-n process packets 2-1, 2-2, and 2-n, which are composed of predetermined frames, respectively. And send and receive. Wireless power receivers 110-1, 110-2, and 110-n include, for example, mobile communication terminals, personal digital assistants (PDAs), personal multimedia players (PMPs), and smartphones. Can be embodied in.

0024The wireless power transmitter 100 wirelessly supplies power to a plurality of wireless power receivers 110-1, 110-2, and 110-n by using a resonance method. When the wireless power transmitter 100 uses the resonance method, the distance between the wireless power transmitter 100 and the plurality of wireless power receivers 110-1, 110-2, 110-n can be preferably 30 m or less. .. However, when the wireless power transmitter 100 uses the electromagnetic induction method, the distance between the wireless power transmitter 100 and the wireless power receivers 110-1, 110-2, and 110-n is preferably 10 cm or less. possible.

0025The wireless power receivers 110-1, 110-2, and 110-n charge the internally mounted battery by receiving wireless power from the wireless power transmitter 100. Further, the wireless power receivers 110-1, 110-2, and 110-n are signals requesting transmission of wireless power, information for receiving wireless power, status information of the wireless power receiver, and wireless power transmitter 100. Control information and the like can be transmitted to the wireless power transmitter 100.

0026The wireless power receivers 110-1, 110-2, and 110-n transmit a message indicating the charging status of each to the wireless power transmitter 100.

0027The wireless power transmitter 100 has the respective states of the wireless power receivers 110-1, 110-2, and 110-n based on the messages received from the wireless power receivers 110-1, 110-2, and 110-n. Includes a display that displays. The wireless power transmitter 100 also displays the estimated remaining time until charging of the wireless power receivers 110-1, 110-2, and 110-n is complete.

0028Further, the wireless power transmitter 100 transmits a control signal for disabling the wireless charging function of the wireless power receivers 110-1, 110-2, and 110-n. Basically, when receiving the disable control signal of the wireless charging function from the wireless power transmitter 100, the wireless power receiver disables the wireless charging function.

0029FIG. 2A is a block diagram showing a configuration of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

0030Referring to FIG. 2A, the wireless power transmitter 200 includes a power transmitter 211, a control unit 212, and a communication unit 213. The wireless power receiver 250 includes a power receiving unit 251, a control unit 252, and a communication unit 253. Here, the term'unit'means a hardware device or a combination of hardware and software.

0031The power transmitting unit 211 wirelessly supplies power to the wireless power receiver 250 via the power receiving unit 251. The power transmitter 211 supplies power in an alternating current (AC) waveform. However, when the power transmission unit 211 receives power from the battery in a DC waveform, for example, the power transmission unit 211 converts the DC waveform into an AC waveform using an inverter and then supplies the power in the AC waveform. The power transmitter 211 can be embodied in a built-in battery or in a power receiving interface, receiving power from an external source, such as an outlet, and supplying it to other components. It can also be embodied in form. Those skilled in the art will easily understand that there is no limit as long as the power transmitter 211 can supply AC waveform power.

0032In addition, power transmitter 211 can provide the AC waveform to the wireless power receiver 250 in the form of electromagnetic waves. Therefore, the power transmitter 211 may also include an additional loop coil, which allows it to transmit or receive a predetermined electromagnetic wave. When the power transmitter 211 is embodied in a loop coil, the inductance (L) of the loop coil may be changeable. Those skilled in the art will easily understand that there are no restrictions as long as the power transmitter 211 can transmit and receive electromagnetic waves.

0033The control unit 212 controls the overall operation of the wireless power transmitter 200 using an algorithm, program, or application read from memory (not shown). The control unit 212 can be embodied in a central processing unit (CPU), a microprocessor, a minicomputer, or the like.

0034Communication unit 213 includes Near Field Communication (NFC), Zigbee, Infrared Data Association (IrDA), Visible Ray Communication (VLC), Bluetooth® method, and Bluetooth Low Energy (Bluetooth® low energy). : BLE) Communicates with the communication unit 253 in the wireless power receiver 250 using the method or the like. In addition, the communication unit 213 executes communication using the Jigbee communication method or the BLE method of the IEEE802.15.4 method. In addition, Communication Unit 213 uses the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) algorithm.

0035The communication unit 213 transmits a signal associated with the information of the wireless power transmitter 200. For example, the communication unit 213 executes unicast, multicast, or broadcast of this signal.

0036Table 1 below shows the data structure of the signal transmitted from the wireless power transmitter 200 at predetermined intervals according to one embodiment of the present invention.

0037<tables num="1"><img id="000003" he="25" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0038In Table 1, the'frame type'field, which indicates the type of signal, indicates that the corresponding signal is a Notice signal. Also, the'protocol version'field, which indicates the type of communication protocol, may be allocated, for example, 4 bits, and the'sequence number'field, which indicates the sequential order of the corresponding signals, may be allocated, for example, 1 byte. The sequence number increases with the signal transmission / reception step.

0039The'Network ID' field, which indicates the network identifier of the wireless power transmitter 200, indicates, for example, the wireless power receiver to which 1 byte is allocated and performs the report to the wireless power transmitter 200.'Report target Rx (schedule mask) 'The field can be allocated, for example, 1 byte.

0040Table 2 below shows an example of the'reportable Rx (schedule mask)' field according to one embodiment of the present invention.

0041<tables num="2"><img id="000004" he="26" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0042In Table 2, Rx1 to Rx8 correspond to the first to eighth radio power receivers, respectively. Based on Table 2, the schedule mask number is displayed as '1', i.e. the radio power receivers of Rx1, Rx6, Rx7, and Rx8 can make the report.

0043In Table 1, the'Spare'field reserved for future use is, for example, the'Rx Count'field, which indicates the number of wireless power receivers that are allocated 5 bits and are adjacent to the wireless power transmitter 200. , For example, 3 bits are assigned.

0044The frame type signals in Table 1 can be embodied to be assigned to Wireless Power Transmission (WPT) in the IEEE802.15.4 data structure.

0045Table 3 shows the IEEE 802.15.4 data structure.

0046<tables num="3"><img id="000005" he="16" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0047As shown in Table 3, the IEEE802.15.4 data structure includes the'preamble','start frame delimiter (SFD)',' frame length',' WPT', and cyclic redundancy check (CRC) 16'fields. .. Also, the data structures shown in Table 1 may be included in the WPT fields of Table 3.

0048The communication unit 213 receives power information from the wireless power receiver 250. Here, the power information may include at least one of the capacity, battery level, number of charges, usage, battery capacity, and battery ratio of the wireless power receiver 250. Further, the communication unit 213 transmits a charging function control signal for controlling the charging function of the wireless power receiver 250. For example, the charging function control signal enables or disables the charging function by controlling the wireless power receiver 251 in a specific wireless power receiver 250.

0049Further, the communication unit 213 receives a signal from another wireless power transmitter (not shown). For example, the communication unit 213 may receive the communication signal of the form shown in Table 1 described above from another wireless power transmitter.

0050Although the power transmission unit 211 and the communication unit 213 are shown in different hardware structures in FIG. 2A, the power transmission unit 211 and the communication unit 213 may be configured by one hardware structure.

0051The wireless power transmitter 200 and the wireless power receiver 250 transmit and receive various signals. Using such a function, according to one embodiment of the present invention, the charging process is provided by subscribing the wireless power receiver 250 to the wireless power network managed by the wireless power transmitter 200.

0052FIG. 2B is a block diagram showing a configuration of a wireless power receiver according to an embodiment of the present invention.

0053Referring to FIG. 2B, the wireless power receiver 250 includes a power receiver 251, a control unit 252, a communication unit 253, a rectifier unit 254, a DC / DC converter 255, a switching unit 256, and a charging unit 257. Since the description of the power receiving unit 251, the control unit 252, and the communication unit 253 has already been provided in connection with FIG. 2A, a repetitive description will be omitted here.

0054The rectifying unit 254, for example, the bridge diode, rectifies the radio power received from the power receiving unit 251 in the form of DC power. The DC / DC converter 255 converts the rectified power with a predetermined gain. For example, the DC / DC converter 255 converts the power rectified so that the voltage at its output end 259 is 5V. The minimum and maximum values of the voltage that can be applied to the front end 258 of the DC / DC converter 255 can already be set, and information on these values can be found in more detail on the'input voltage MIN'of the join request signal, which will be described later. It can be recorded in the field and the'input voltage MAX'field respectively. The rated voltage value and rated current value applied to the rear end 259 of the DC / DC converter 255 are the typical output voltage field of the subscription request signal and the typical output current (Typical Output Current). ) Can be listed in the field.

0055The switching unit 256 connects the DC / DC conversion unit 255 to the charging unit 257 under the control of the control unit 252. The charging unit 257 stores the converted power received from the DC / DC converter 255 when the switching unit 256 is in the ON state.

0056FIG. 3 is a flowchart showing a wireless power transmission / reception method according to an embodiment of the present invention. Referring to FIG. 3, the wireless power transmitter detects an object located in the vicinity of the wireless power transmitter in step S301. For example, when detecting a load change, the wireless power transmitter determines if a new object is located in the vicinity of the wireless power transmitter. Alternatively, the wireless power transmitter detects nearby objects based on voltage, current, phase, temperature, and so on.

0057In step S303, the wireless power receiver searches for a wireless power transmitter that receives wireless power on at least one channel. For example, a wireless power receiver transmits a wireless power transmitter search signal to at least one wireless power transmitter and wireless power is based on the wireless power transmitter search response signal received in response to the wireless power transmitter search signal. Select the wireless power transmitter to receive. In addition, the wireless power receiver can form a communication network with a wireless power transmitter that receives wireless power.

0058In step S305, the wireless power receiver joins the wireless power network managed by the wireless power transmitter that receives the wireless power. For example, a wireless power receiver sends a Request Join signal to a wireless power transmitter that receives wireless power, and in response, the wireless power receiver receives a join response signal from the wireless power transmitter. Receive (Response Join signal). The subscription response signal may include subscription permission / prohibition information, which is used to determine whether participation in a wireless power network managed by a wireless power transmitter is permitted.

0059In step S307, the wireless power transmitter and the wireless power receiver enter the standby state. The wireless power transmitter transmits a command signal to the wireless power receiver. The radio power receiver transmits a report signal or an acknowledgment (Ack) signal according to the received instruction signal. In step S309, the wireless power receiver can start charging if the command signal includes a charge start command.

0060FIG. 4A is a circuit diagram showing a wireless power transmitter according to an embodiment of the present invention. Referring to FIG. 4A, the wireless power transmitter includes an input end 401 that receives a drive voltage VDD. The first end of the coil 402 is connected to the input end 401, the second end of the coil 402 is connected to the node 403, and the node 403 is one end of the field effect transistor (FET) element 404, of the coil 406. One end and one end of the capacitor 405 are connected. The other end of the FET element 404 is grounded. The other end of the capacitor 405 is also grounded. The other end of the coil 406 is connected to one end of the capacitor 407. The second end of capacitor 407 is connected to filter 409, which is connected to one end of capacitor 410 and one end of coil 412. The other end of the capacitor 410 is grounded.

0061The wireless power transmitter measures the load or impedance at the input end 401 to detect an object in the vicinity of the wireless power transmitter. For example, if a new object is placed near a wireless power transmitter, an abrupt load change will be detected. Therefore, the wireless power transmitter determines that a new object has been placed in the vicinity.

0062Similarly, the wireless power transmitter measures the load or impedance at the input end 401 to detect that a nearby object has moved far away. For example, if the measured load suddenly decreases, the wireless power transmitter determines that there are no objects placed in its vicinity.

0063The wireless power transmitter detects the load at the front end 408 or the rear end 411 of the filter 409 in addition to the input end 410. That is, the wireless power transmitter determines the absence of a new object or object in the vicinity by detecting the load at various parts. Alternatively, the wireless power transmitter determines the absence of a new object or object in the vicinity based on the voltage or current value.

00644B and 4C are graphs showing currents and voltages measured over time by a wireless power transmitter according to an embodiment of the present invention, respectively. In FIG. 4B, the current value measured at one point of the wireless power transmitter from the start of the measurement to the time point t1 is'a'. After time point t1, the measured current value is'b'. As can be seen from the graph in FIG. 4B, the current value has a sudden change from'a'to'b' at time point t1. In addition, the wireless power transmitter can determine the absence of a new object in the vicinity of the wireless power transmitter or an object in front of the vicinity by detecting a sudden change.

0065In FIG. 4C, the current value measured at one point of the wireless power transmitter from the start of the measurement to the time point t1 is'c'. After time point t1, the measured voltage value is'd'. As can be seen from the graph in FIG. 4C, the voltage value has a sudden change from'c'to'd' at time point t1. In addition, the wireless power transmitter can determine the absence of a new object in the vicinity of the wireless power transmitter or an object in front of the vicinity by detecting a sudden change.

0066FIG. 4D is a graph showing the temperature measured over time at one point of the wireless power transmitter according to one embodiment of the present invention. With reference to Figure 4D, the temperature measured at one point on the wireless power transmitter increases linearly. In particular, the temperature measured at one point of the wireless power transmitter increases with the slope of'e'up to a certain point in time t1. After point t1, the temperature increases with a slope of'f'. As can be seen from Figure 4D, the increasing slope with respect to temperature suddenly changes from'e'to'f' at time point t1. In addition, the wireless power transmitter can determine the absence of a new object in the vicinity of the wireless power transmitter or an object in front of the vicinity by detecting a sudden change.

0067FIG. 4E is a graph showing the phase of the wireless power transmitter according to the embodiment of the present invention at one point. Referring to FIG. 4E, the voltage 421 and the current 422 at one point of the wireless power transmitter do not overlap each other up to a certain point in time. After a certain point in time, the phase of the wireless power transmitter is changed at one point, so that the voltage 421 and the current 422 may partially overlap. Power loss occurs when the voltage 421 and the current 422 partially overlap. That is, the wireless power transmitter detects a sudden phase change by detecting a power loss. The radio power transmitter determines the absence of a new object in the vicinity or an object in front of the vicinity by detecting a sudden change.

0068The wireless power transmitter also determines the proximity of the object using an IR sensor or based on user input.

0069FIG. 5 is a timing diagram showing load detection and signal transmission of the wireless power transmitter according to the embodiment of the present invention. With reference to FIG. 5, the control unit (TX MCU) 501 of the wireless power transmitter determines the channel and network ID to execute the communication in step S510. For example, the wireless power transmitter sets any one of channels 11, 15, 20, and 24 in the IEEE 802.15.4 system as a communication channel. In addition, the wireless power transmitter sets the network ID so as not to overlap with other wireless power transmitters 503 in the communication channel.

0070The control unit 501 holds the detection state in which the detection powers 513 and 516 are transmitted during the detection period tdet valid in the specified detection period tdet_per in steps S502 and S515.

0071Therefore, the control unit 501 of the wireless power transmitter detects the object in step S511. The size of the detected power and the effective detection period is determined by whether the control unit 501 has a candidate device for wireless charging within an effective range by detecting a change in the load value of the power transmitter, that is, the resonator. It is determined by the minimum amount of power and time used to determine whether or not. This is because the candidate device, i.e. the metal object, is sensed from the change in the load of the resonator, so that the control unit 501 sends a sine wave with a low voltage that is sized to sense the load value of the resonator. The power consumption in the detected state is minimized by generating it periodically during the short time required to detect the load value. This detection state is retained for a valid detection period until a new device is detected.

0072For example, when a wireless power receiver is placed on or over the wireless power transmitter, control 501 detects a load change and confirms that the object is placed around itself. For example, the control 501 detects a sudden change in load, as shown in FIG. 4A, or detects a sudden change in various other criteria as shown in FIGS. 4B-4E.

0073In FIG. 5, it is assumed that the control unit 501 does not detect a sudden change. Therefore, the control unit 501 applies the detection powers 513 and 516 in a predetermined detection period without changing the applied power.

0074Further, the communication unit (TX RF) 502 transmits a communication signal in a predetermined period in steps S514 and S517. For example, the communication signal has the data structure shown in Table 1 described above.

0075The other wireless power transmitter 503 that uses the communication channel receives the notification signal transmitted from the communication unit 502. The notification signal can indicate the network ID of the wireless power transmitter or indicate the schedule of the wireless power receiver performing communication with the wireless power transmitter, as described above in connection with Table 1. In addition, the notification signal is transmitted for a predetermined period of time, for example, every 270 ms, and therefore may be used as a synchronization signal.

00766A and 6B are timing diagrams showing a power supply operation between the wireless power transmitter and the wireless power receiver according to the embodiment of the present invention. Referring to FIG. 6A, the control unit 650 of the wireless power transmitter detects the load change in step S601 by applying the detection power 602 at predetermined intervals. In addition, the communication unit 660 transmits a notification signal at predetermined intervals in step S603. In FIG. 6A, the control unit 650 of the wireless power transmitter does not detect a sudden change in load in step S601.

0077In step S604, user 695 locates the wireless power receiver in the vicinity of the wireless power transmitter.

0078In step S607, the control unit 650 further applies the detection power after a predetermined period of time to detect a sudden change in load caused by arranging the receiver in step 604. The control unit 650 applies a drive power (or registered power) Preg greater than the detection power 602 when the device is detected within the valid detection period. Here, the drive power drives the control unit 690 of the wireless power receiver.

0079Therefore, in step S605, the control unit 690 is driven (or powered on), and in step S606, the communication unit 680 is initialized. On the other hand, the control unit 650 determines the existence of the wireless power receiver based on the presence of pulse initiated by the control unit 690. The control unit 650 can update the wireless power receiver whose existence is determined by the control unit 650 in the device control table.

0080FIG. 18 is an exemplary diagram showing an apparatus control table according to an embodiment of the present invention. Referring to FIG. 18, the device control table shows the respective session ID, manufacturer ID, product ID, load characteristic, current characteristic, voltage characteristic, efficiency characteristic, current state, DC of the wireless power receiver of the wireless power receiver. Information on the voltage at the front end of the (DC) / DC converter, the voltage at the rear end of the DC / DC converter of the wireless power receiver, and the current at the rear end of the DC / DC converter of the wireless power receiver, etc. Used to manage. Here, the current state is whether the wireless power receiver is in the standby state after charging is completed, the wireless power receiver is in the standby state due to insufficient charging power, or the wireless power receiver is in a constant voltage. : CV) indicates whether the battery is charging or the wireless power receiver is charging in constant current (CC) mode.

0081Further referring to FIG. 6A, the communication unit 680 uses the second channel under the control of the control unit 690. In the example of FIG. 6A, the second channel is used by the wireless power transmitter 670 and is different from the channel used by the communicator 660. Therefore, the channel used by the communication unit 660 is called the'first channel'.

0082The order in which the control unit 690 determines the search channel has already been set, and is set using, for example, channel 11, channel 24, channel 15, and channel 20 of IEEE802.15.4. Further, the initial search channel searched by the control unit 690 is randomly determined.

0083In step S610, the communication unit 680 transmits the wireless power transmitter search signal on the second channel. For example, the wireless power transmitter search signal has a data structure as shown in Table 4 below.

0084<tables num="4"><img id="000006" he="20" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0085In Table 4, the'frame type'field indicating the type of signal indicates that the corresponding signal is a search signal. Also, the'protocol version'field, which indicates the type of communication protocol, may be allocated, for example, 4 bits, and the'sequence number'field, which indicates the sequential order of the corresponding signals, may be allocated, for example, 1 byte. For example, the sequence number increases with the signal transmission / reception step. That is, when the sequence number of the notification signal in Table 1 is 1, the sequence number of the search signal in Table 4 is 2.

0086The'Manufacturer ID'field indicating the manufacturer information of the wireless power receiver is, for example, 1 byte allocated, and the'Product ID' field indicating the product information of the wireless power receiver is, for example, the serial number of the wireless power receiver. Information is provided. For example, 4 bytes are allocated. The'impedance'field, which indicates the impedance information of the wireless power receiver, is assigned, for example, 4 bits, and the'class' field, which indicates the rated power information of the wireless power receiver, is assigned, for example, 4 bits. Be done.

0087In FIG. 6A, for example, the three radio power transmitters use the second channel. In steps S611, S613, and S615, each of the three wireless power transmitters 670 transmits a wireless power transmitter search response signal to the communication unit 680 in response to the wireless power transmitter search signal.

0088The wireless power transmitter search response signal, that is, the Response Search signal, has a data structure as shown in Table 5.

0089<tables num="5"><img id="000007" he="20" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0090In Table 5, the'frame type'field indicating the type of signal indicates that the corresponding signal is a search response signal. The'spare'field reserved for future use is, for example, assigned 4 bits. The'sequence number'field, which indicates the sequential order of the corresponding signals, may be allocated, for example, 1 byte. For example, the sequence number increases with, for example, the signal transmission / reception step. The'Network ID'field, which indicates the network identifier of the wireless power transmitter, is allocated, for example, 1 byte.

0091In steps S612, S614, and S616, the control unit 690 uses three radio power transmitters 670 that use the second channel based on the radio power transmitter search response signal received via the second channel. Identify the channel information and network ID information for each of the. Further, the control unit 690 stores the identified channel information, network ID information, and channel-specific RSSI strength in step S617.

0092In step S618, the communication unit 680 transmits a search signal. If the search response signal corresponding to the search signal is not received, the communication unit 680 further transmits the search signal twice in steps S619 and S620. If the communication unit 680 does not receive the corresponding search response signal even after transmitting the search signal three times, the control unit 690 changes or switches the search channel to another channel.

0093In FIG. 6A, the control unit 690 changes, for example, the search channel to the first channel. In step S621, the communication unit 680 transmits a search signal using the first channel. The communication unit 660 receives the search signal, and the control unit 650 updates the device control table shown in FIG. 18 based on the search signal in step S622. Further, the control unit 650 generates a search response signal corresponding to the search signal.

0094In step S623, the communication unit 660 transmits the generated search response signal to the communication unit 680.

0095The control unit 690 identifies the channel information and the network ID information of the wireless power transmitter using the first channel in step S624 based on the search response signal received via the first channel. In addition, the control unit 690 can store the identified channel information, network ID information, and RSSI strength for each channel. The communication unit 680 further transmits the search signal three times in steps S625, S626, and S627.

0096After this, the wireless power receiver determines in step S628 the communication channel on which to perform the communication and the wireless power transmitter to receive the wireless power. That is, based on this stored channel information and RSSI information, the wireless power receiver determines the communication channel and the wireless power transmitter that receives the wireless power. For example, a wireless power receiver can determine the channel with the lowest RSSI value as the communication channel. After this, the communication unit 680 of the wireless power receiver forms a pairing with the communication unit 660. After this, the wireless power transmitter and receiver enter the subscribed state.

0097In step S629, the radio power receiver generates a subscription request signal based on information about the determined communication channel and the radio power transmitter receiving the determined radio power. The communication unit 680 transmits the generated subscription request signal to the communication unit 660 in step S630. For example, the subscription request signal has a data structure as shown in Table 6.

0098<tables num="6"><img id="000008" he="20" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0099In Table 6, the'frame type'field indicating the type of signal indicates that the corresponding signal is a join request signal. Also, the'spare'field reserved for future use is allocated, for example, 4 bits. The'sequence number'field, which indicates the sequential order of the corresponding signals, is allocated, for example, 1 byte. For example, the sequence number increases with the signal transmission / reception step.

0100The'Network ID'field, which indicates the network identifier of the wireless power transmitter, is allocated, for example, 1 byte. The'Product ID'field indicating the product information of the wireless power receiver is assigned, for example, the serial number information of the wireless power receiver, for example, 4 bytes. The'input voltage MIN'field, which indicates the minimum voltage value applied to the front end of the DC / DC inverter (not shown) of the wireless power receiver, is assigned, for example, 1 byte, and the DC / DC inverter of the wireless power receiver. The'Input Voltage MAX'field, which indicates the maximum voltage value applied to the rear end (not shown), is assigned, for example, 1 byte to the rear end of the DC / DC inverter (not shown) of the wireless power receiver. The'typical output voltage'field, which indicates the rated voltage value applied to, is assigned, for example, 1 byte, and the rated current applied to the rear end of the DC / DC inverter (not shown) of the wireless power receiver. For example, 1 byte is allocated to the'typical output current'field indicating the value.

0101In step S630, the control unit 650 of the wireless power transmitter determines whether or not to subscribe the wireless power receiver to the wireless power network based on the received subscription request signal. The control unit 650 of the wireless power transmitter can determine whether or not to join the wireless power receiver to the wireless power network based on the device control table as shown in FIG. For example, if the wireless power receiver requests a larger amount of power than the available power that the wireless power transmitter can supply, the wireless power transmitter may not allow the wireless power receiver to join. ..

0102When the wireless power transmitter determines that the wireless power receiver joins the wireless power network, the control unit 650 assigns the session ID to the wireless power receiver. The control unit 650 generates a Response Join signal including a session ID or join permission / prohibition information. In step S632, the control unit 650 controls the communication unit 660 so as to transmit the generated subscription response signal to the communication unit 680 of the wireless power receiver.

0103For example, the subscription response signal has a data structure as shown in Table 7.

0104<tables num="7"><img id="000009" he="20" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0105In Table 7, the'frame type'field, which indicates the type of signal, indicates that the corresponding signal is a join response signal. Also, the'spare'field reserved for future use is allocated, for example, 4 bits. The'sequence number'field, which indicates the sequential order of the corresponding signals, is allocated, for example, 1 byte. For example, the sequence number increases with the signal transmission / reception step.

0106The'Network ID'field, which indicates the network ID of the wireless power transmitter, is, for example,'permitted', indicating whether 1 byte is allocated and the wireless power receiver is allowed or prohibited from joining the wireless power network. The field is assigned, for example, 4 bits. For example, if the'Allow'field indicates '1', it indicates that the wireless power receiver has been permitted to join, but if the'Allow'field indicates '0', it indicates that the wireless power receiver has been subscribed. Indicates that is not allowed. The'Session ID'field indicates the session ID that the wireless power transmitter assigns to the wireless power receiver to control the wireless power network. For example, 4 bits are assigned to the'session ID'.

0107On the other hand, the communication unit 680 of the wireless power receiver can transmit the subscription request signal until the subscription response signal is received from the communication unit 660 of the wireless power transmitter.

0108In step S633, the control unit 690 of the wireless power receiver determines whether or not the subscription is permitted by analyzing the received subscription request signal, and identifies the assigned session ID.

0109The communication unit 680 transmits an Ack signal to the communication unit 660 in step S635. The communication unit 660 can transmit the subscription response signal until it receives the Ack signal from the communication unit 680. In step S636, the control unit 650 identifies the Ack signal by the channel and network ID, and in step S637, registers the subscription of the wireless power receiver to the wireless power network. For example, the control unit 660 manages the subscribed wireless power receiver using the device control table as shown in FIG.

0110Further, the control unit 660 can control the subscribed wireless power receiver to enter the standby state. For example, the control unit 660 causes the wireless power receiver to be in a standby state when the charging of the wireless power receiver is completed or the transmission power is not sufficient to charge the capacity of the charging unit of the wireless power receiver. To control.

0111In step S638, the control unit 650 detects the current load and confirms that the load has not changed. In step S639, the control unit 650 increases the applied power to the charging power for charging. In step S640, the communication unit 660 of the wireless power transmitter transmits a notification signal indicating the wireless power receiver that performs communication in the wireless power receiver. The control unit 650 of the wireless power transmitter indicates a wireless power receiver that executes communication using the report target Rx (schedule mask) field of the notification signal.

0112In step S641, the communication unit 660 transmits a command signal to start charging. Basically, the instruction signal indicates an instruction item executed by the wireless power receiver. For example, the command signal has a data structure as shown in Table 8.

0113<tables num="8"><img id="000010" he="19" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0114In Table 8, the'frame type'field, which indicates the type of signal, indicates that the corresponding signal is an instruction signal. The'Session ID'field indicates the session ID that the wireless power transmitter assigns to each wireless power receiver to control the wireless power network. For example, 4 bits are assigned to the'session ID'. The'sequence number'field, which indicates the sequential order of the corresponding signals, is allocated, for example, 1 byte. The sequence number increases with the signal transmission / reception step. The'Network ID'field, which indicates the network identifier of the wireless power transmitter, is allocated, for example, 1 byte, and the'Instruction Type'field, which indicates the type of instruction, is allocated, for example, 4 bits, and is variable to replenish the instruction signal. The (Variable) field is assigned, for example, 4 bits.

0115The'instruction type'field and the'variable'field have various embodiments as shown in Table 9.

0116<tables num="9"><img id="000011" he="59" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0117In Table 9,'start charging' is an instruction that causes the wireless power receiver to start charging. 'Charging end' is an instruction to cause the wireless power receiver to end charging. A'report request'is an instruction that causes a wireless power receiver to transmit a report signal. A'reset'is an initialization instruction and a'channel scan'is an instruction to scan a channel. 'Change channel' is an instruction to change the communication channel.

0118In step S642, the control unit 690 of the wireless power receiver can start charging based on the command signal. In step S643, the control unit 690 of the wireless power receiver starts charging by turning on the switching unit between the DC / DC conversion unit and the charging unit.

0119In step S644, the communication unit 680 transmits an Ack signal, and in step S645, the communication unit 660 transmits a command signal requesting a report. The command signal is a command signal whose command type is a report request.

0120Upon receiving the instruction signal transmitted in step S646, the control unit 690 measures the current power status in step S647. In step S648, the control unit 690 generates a report signal including the current power status information based on the result of this measurement. In step S649, the communication unit 680 transmits the generated report signal to the communication unit 660.

0121Here, the report signal is a signal that reports the current state of the wireless power receiver to the wireless power transmitter. For example, the reporting signal has a data structure as shown in Table 10.

0122<tables num="10"><img id="000012" he="18" wi="169" file="JP2017195770A_D0001.tif" img-format="tif" img-content="drawing" /></tables>

0123In Table 10, the'frame type'field indicating the type of signal indicates that the corresponding signal is a reporting signal. The'Session ID'field indicates the session ID that the wireless power transmitter attaches to the wireless power receiver to control the wireless power network. For example, 4 bits are assigned to the'session ID'. In addition, the'sequence number'field, which indicates the sequential order of the corresponding signals, is allocated, for example, 1 byte. The sequence number increases with, for example, the signal transmission / reception step.

0124The'Network ID'field, which indicates the network ID of the wireless power transmitter, is, for example, a'input'that is allocated 1 byte and indicates the voltage value applied to the front end of the DC / DC inverter (not shown) of the wireless power receiver. The'voltage'field is assigned, for example, 1 byte, and the'output voltage' field applied to the rear end of the DC / DC inverter (not shown) of the wireless power receiver is, for example, 1 byte allocated, wireless. The'output current'field, which indicates the rated current value applied to the rear end of the DC / DC inverter (not shown) of the power receiver, is assigned, for example, 1 byte.

0125The wireless power transmitter can transmit a command signal until it receives a report signal or an Ack signal from the wireless power receiver. If the radio power transmitter is unable to receive a report signal or Ack signal from a particular radio power receiver during the allotted time, the radio power transmitter will be sent to the specific radio power receiver during the additional time. The command signal can be retransmitted.

0126FIG. 7 is a flowchart showing a method of a wireless power transmitter according to an embodiment of the present invention. Referring to FIG. 7, the wireless power transmitter periodically outputs the detected power for detecting the load change in step S701. If no load change is detected (No in step S703), the wireless power transmitter periodically continuously outputs the detected power in step S701. However, if a load change is detected (Yes in step S703), the wireless power transmitter outputs drive power for communication with the wireless power receiver in step S705. For example, the drive power is the amount of power that can drive the control unit of the wireless power receiver.

0127In step S707, the wireless power transmitter determines whether to receive the search signal within a predetermined period of time. If the search signal is not received within a predetermined period (No in step S707), the wireless power transmitter outputs the detected power in step S701. However, if the search signal is received within a predetermined period (Yes in step S707), the wireless power transmitter will generate and transmit the search response signal in step S709. In step S711, the wireless power transmitter receives the subscription request signal, and in step S713, generates and transmits the subscription request signal in response to the subscription request signal.

01288A and 8B are timing diagrams showing an operation in which a wireless power receiver according to an embodiment of the present invention fails to join a wireless power network managed by a wireless power transmitter. Referring to FIG. 8A, the control unit 801 of the wireless power transmitter periodically outputs the detected power 812 in steps S811 and S815, executes load detection, and periodically sends a notification signal in steps S813 and S816. Send.

0129In step S817, user 805 locates the radio power receiver at the radio power transmitter, and control unit 801 detects the load change in step S814. In step S818, the control unit 801 increases the applied power to the drive power by the value 815, and the communication unit 803 of the wireless power receiver is initialized by the control unit 804 of the wireless power receiver. In steps S819 to S827, the communication unit 803 transmits a wireless power transmitter search signal and a wireless power transmitter search response signal on another channel, and stores related information. In addition, in steps S828 to S830, the communication unit 803 transmits the wireless power transmitter search signal and the wireless power transmitter search response signal by changing the channel, and stores the related information.

0130The control unit 804 determines the wireless power transmitter that receives the wireless power in step S831, and generates a subscription request signal in step S832. The communication unit 803 transmits the generated subscription request signal to the communication unit 802 in step S833.

0131In step S834, the control unit 801 permits the wireless power receiver to join and assigns the session ID to the wireless power receiver. In step S835, the communication unit 802 transmits the subscription response signal to the communication unit 803. However, in FIGS. 8A and 8B, the subscription response signal cannot be received by the communication unit 803 of the wireless power receiver.

0132Since the communication unit 803 cannot receive the subscription response signal in step S835, the communication unit 803 retransmits the subscription request signal in step S836. However, the retransmitted subscription request signal is not received by the communication unit 802. Since the subscription response signal was not received, the communication unit 803 retransmits the subscription request signal in step S837.

0133In step S838, the control unit 801 permits the wireless power receiver to join and assigns the session ID to the wireless power receiver. In step S839, the communication unit 802 transmits the subscription response signal to the communication unit 803.

0134In step S840, the communication unit 803 transmits an Ack signal to the subscription response signal to the communication unit 802. However, the Ack signal is not received by the communication unit 802.

0135The control unit 801 confirms that three signal transmission / reception failures have occurred during the registration time limit (or subscription time limit) Registration_limit, and notifies the occurrence of an error in step S841. Here, '3 times' is just an example and can be changed.

0136In step S841, the control unit 801 of the wireless power transmitter according to another embodiment of the present invention can immediately notify this error when the registration time limit elapses, regardless of the number of signal transmission / reception failures. ..

0137For error notification, a visual or auditory display device is used, for example, to generate a beep or LED blinking. In addition, the occurrence of an error is output on the display unit (not shown).

0138In step S842, the control unit 801 determines whether or not to eliminate the cause of the error by detecting the load. Notification of the occurrence of the error is repeated in step S843 until the wireless power receiver is removed from the wireless power transmitter. The control unit 801 determines whether or not to remove the radio power receiver based on whether or not the load has returned to the first load.

0139Therefore, in steps S842 and S845, the control unit 801 periodically applies the detection power 812 and determines whether or not the load has returned to the first load. In step S844, user 805 removes the wireless power receiver from the wireless power transmitter, so that when the load returns to the first load, the wireless power transmitter control unit 801 interrupts notification of the occurrence of an error. ..

01409A and 9B are timing diagrams showing a method for determining removal of a wireless power receiver from a wireless power network managed by a wireless power transmitter according to an embodiment of the present invention. Referring to FIG. 9A, the wireless power transmitter outputs a charging power of 900 to the wireless power receiver. In step S911, the communication unit 902 of the wireless power transmitter transmits a notification signal. The wireless power receiver determines whether to execute the communication by identifying the'report target Rx (schedule mask)' field in the notification signal.

0141The control unit 901 of the wireless power transmitter controls the communication unit 902 so as to generate an instruction signal including the session ID information in step S912 and transmit the instruction signal to the communication unit 903 of the wireless power receiver in step S913. To do. The control unit 904 of the wireless power receiver analyzes the command signal in step S914 and generates a report signal containing information about the current power status in step S915. The communication unit 903 transmits the generated report signal to the communication unit 902 in step S916. In step S917, the control unit 901 executes impedance matching and the like based on the received report signal.

0142User 905 removes the wireless power receiver in step S918. The control unit 901 detects a load change in step S919. The communication unit 902 transmits a notification signal in step S920, and transmits a command signal in step S921. The communication unit 902 does not receive the report signal in step S922 due to the removal of the wireless power receiver. In steps S921 and S923, the communication unit 902 of the wireless power transmitter continuously transmits the command signal during one subframe cycle, which is the period during which the notification signal is transmitted. However, the communication unit 902 cannot receive the corresponding report signal in steps S922 and S924.

0143The control unit 901 further executes load detection in step S925, transmits a notification signal during one subframe cycle in step S926, and transmits a command signal in steps S927 and S929. During the corresponding cycle, the communication unit 902 cannot receive the report signal in steps S928 and S930. The control unit 901 further executes load detection in step S931, transmits a notification signal during the next one subframe cycle in step S932, and transmits a command signal in steps S933 and S935. During the corresponding cycle, the communication unit 902 of the wireless power transmitter cannot receive the report signal in steps S934 and S936.

0144If the communication unit 902 cannot receive the report signal or the Ack signal even during the three subframe cycles, the control unit 901 determines in step S937 that the radio power receiver is removed. As a result, the control unit 901 reduces the applied power of the detected power by the value 938.

0145After that, the control unit 901 further executes load detection by periodically applying the detection power in step S939, and the communication unit 902 transmits a notification signal in step S940. As described above, the wireless power transmitter can reliably grasp whether or not the wireless power receiver is removed, thereby contributing to the prevention of power waste.

0146FIG. 10 is a flowchart showing a method for joining a wireless power receiver and transmitting charging power in the wireless power transmitter according to an embodiment of the present invention. In FIG. 10, it is assumed that the wireless power transmitter and one wireless power receiver are already performing charging.

0147Referring to FIG. 10, the wireless power transmitter transmits the first charge power to the first wireless power receiver in step S1001. The user then places a second radio power receiver on or near the radio power transmitter.

0148The radio power transmitter detects a load change in step S1003 based on the placement of the second radio power receiver. If the wireless power transmitter cannot detect the load change (No in step S1003), it continuously transmits the first charge power to the first wireless power receiver in step S1001.

0149However, if the wireless power transmitter detects a load change (Yes in step S1003), in step S1005, the second wireless power receiver sends a search signal and the wireless power transmitter sends a search signal. To receive. In step S1007, the wireless power transmitter generates and transmits a search response signal according to the search signal. Further, in step S1009, the wireless power transmitter receives the subscription request signal from the second wireless power receiver, and in step S1011, transmits the corresponding subscription response signal. Therefore, in step S1013, the second wireless power receiver can join the wireless power network managed by the wireless power transmitter, and the wireless power transmitter further transmits the second charging power.

015011A and 11B are timing diagrams showing a power supply operation between the wireless power transmitter and the two wireless power receivers according to the embodiment of the present invention. Specifically, in FIGS. 11A and 11B, the first wireless power receiver 1103 has already executed charging by receiving the first charging power from the wireless power transmitter.

0151Referring to FIG. 11A, the control unit 1101 of the wireless power transmitter transmits the first charging power 1112 for charging the first wireless power receiver 1103. In step S1111, the control unit 1101 periodically detects the load change using the first charging power 1112. Further, the communication unit 1102 of the wireless power transmitter transmits a notification signal in step S1113. The'RX Count'field of the notification signal contains information indicating that the number of wireless power receivers currently being charged is 1.

0152In step S1114, the control unit 1101 generates an instruction signal including the session ID of the first radio power receiver 1103, and in step S1115, the communication unit 1102 transmits the generated instruction signal. Here, the'report request'is described in the instruction type field of the instruction signal. The first wireless power receiver 1103 measures the current power status of the first wireless power receiver based on the command signal in step S1116, and reports including the current power status of the first wireless power receiver. A signal is generated and a report signal is transmitted to the communication unit 1102.

0153In step S1117, the control unit 1101 manages the power status based on the received report signal and executes impedance matching.

0154The user places the second radio power receiver 1104 on or near the radio power transmitter, and the control unit 1101 detects a sudden change in load in step S1120. The second wireless power receiver 1104 generates a search signal including the product ID in step S1118, and transmits the search signal to the communication unit 1102. The control unit 1101 identifies the product ID of the second wireless power receiver 1104 based on the received search signal, and manages the product ID by registering the product ID in the device control table as shown in FIG. In step S1121, the communication unit 1102 transmits a search response signal corresponding to the search signal.

0155The second wireless power receiver 1004 transmits the subscription request signal to the communication unit 1102 in step S1122. In response to this, the communication unit 1102 transmits a subscription response signal in step S1123. The control unit 1101 determines whether or not to allow the second wireless power receiver 1104 to join, and transmits a subscription response signal including the permission to join. In response, the second radio power receiver 1104 transmits an Ack signal in step S1124 and enters the standby state after joining the network.

0156The control unit 1101 transmits the second charging power 1125 for charging the second wireless power receiver 1104. Further, in step S1126, the communication unit 1102 transmits a command signal including a charge start command to the second wireless power receiver 1104. The second wireless power receiver 1104 executes charging by turning on the switching unit connected to the charging unit based on the instruction signal. Further, the second radio power receiver 1104 transmits an Ack signal in step S1127.

0157The control unit 1101 checks the load change after the lapse of a predetermined period in step S1128. If there is no change in load, the control unit 1101 of the wireless power transmitter transmits the same charging power, that is, the first and second charging powers.

0158The communication unit 1102 transmits a notification signal in step S1129. Further, in steps S1130 and S1132, the communication unit 1102 transmits a command signal to each of the first wireless power receiver 1103 and the second wireless power receiver 1104. In steps S1131 and S1133, the communication unit 1102 receives the report signal from each of the first wireless power receiver 1103 and the second wireless power receiver 1104.

0159After the elapse of the predetermined period, the communication unit 1102 transmits the notification signal in step S1134. Further, in step S1135 and S1137 first, the communication unit 1102 transmits a command signal to each of the first wireless power receiver 1103 and the second wireless power receiver 1104. In steps S1136 and S1138, the communication unit 1102 receives the report signal from each of the first wireless power receiver 1103 and the second wireless power receiver 1104.

0160FIG. 12 is a diagram showing timing division of a wireless power transmitter according to an embodiment of the present invention. Referring to FIG. 12, if the wireless power transmitter manages only the first wireless power receiver 1103, half of the total super-frame cycle communicates with the first wireless power receiver 1103. Allocate as time 1201 for and the other half as contention period 1202. Here, the contention period can be a period allocated in case communication is not executed.

0161Referring to FIG. 12, when the second wireless power receiver 1104 joins the wireless power network, the wireless power transmitter divides the allotted period 1200 into three equal parts and divides them into three parts. Allocate to period 1203 for communication with wireless power receiver 1103, period 1204 for communication with second wireless power receiver 1104, and contention period 1205, respectively.

0162FIG. 13 is a flowchart showing a method of a wireless power transmitter according to an embodiment of the present invention. Referring to FIG. 13, the radio power transmitter transmits a command signal requesting a report signal in step S1301. If the report signal cannot be received, the wireless power transmitter waits for the report signal to be received in the next superframe cycle. If the report signal cannot be received during the next three superframe cycles (Yes in step S1305), the wireless power transmitter determines in step S1307 that the wireless power receiver will be removed. In step S1309, the wireless power transmitter reduces the charging power to charge the wireless power receiver prior to power transfer.

0163However, if the report signal is received (Yes in step S1303), the radio power transmitter transmits the command signal after the next superframe cycle.

0164FIG. 14 is a diagram showing a change in the allocated time due to removal of the wireless power receiver according to the embodiment of the present invention. Referring to FIG. 14, if the wireless power transmitter manages two wireless power receivers, the wireless power transmitter divides the entire superframe cycle into two parts and divides them into the first radio. Allocate to period 1404 for communication with the power receiver, period 1402 for communication with the second wireless power receiver, and retention period 1403, respectively. However, for example, if the second radio power receiver is removed, as shown in FIG. 14, the radio power transmitter divides the entire superframe cycle into two parts and divides them into the first radio. Allocate to period 1404 and contention period 1405 for communication with the power receiver, respectively.

0165FIG. 15 is a diagram showing a device control table that manages a wireless power receiver in a wireless power transmitter according to an embodiment of the present invention. In FIG. 15, the wireless power transmitter manages the first to third wireless power receivers. Therefore, the wireless power transmitter assigns session IDs 1, 2, and 3 to the first to third wireless power receivers, respectively. If it is subsequently determined that the second wireless power receiver will be removed, the wireless power transmitter removes the session ID assigned for the second wireless power receiver from the device control table. .. The wireless power transmitter assigns the session ID of the second wireless power receiver to the third wireless power receiver, as shown in FIG. On the other hand, the wireless power transmitter manages the third wireless power receiver to hold the existing session ID, as shown in FIG.

016616A and 16B are timing diagrams showing an operation of removing one of two wireless power receivers from a wireless power network managed by a wireless power transmitter according to an embodiment of the present invention.

0167Referring to FIG. 16A, the control unit 1601 of the wireless power transmitter transmits the charging power 1612 for charging the first wireless power receiver 1603 and the second wireless power receiver 1604. The control unit 1601 continuously transmits the charging power 1612 when the load change is not detected in step S1611. Further, the communication unit 1602 of the wireless power transmitter transmits the notification signal to the first wireless power receiver 1603 and the second wireless power receiver 1604 in steps S1613 and S1614. The communication unit 1602 generates an instruction signal in step S1615, and transmits the generated instruction signal to the first wireless power receiver 1603 in step S1616. The first radio power receiver 1603 generates a report signal and transmits it to the communication unit 1602 in step S1617. In step S1618, the control unit 1601 grasps the current power situation by analyzing the reported signal and executes impedance matching.

0168In step S1619, the communication unit 1602 transmits a command signal to the second radio power receiver 1604, and in step S1620, receives a report signal from the second radio power receiver 1604.

0169The user removes the first radio power receiver 1603, and the control unit 1601 detects a sudden change in load in step S1621. As described above with reference to FIGS. 4A-4E, the control unit 1601 has the first radio power receiver 1603 removed based on various criteria, eg, loading of the radio power transmitter at various locations. It can be determined whether or not it is possible.

0170In step S1622, the communication unit 1602 transmits a notification signal to the second radio power receiver 1604. In step S1623, the communication unit 1602 transmits the command request report signal to the first radio power reception unit 1603. In step S1624, the first radio power receiver 1603 cannot return the reported signal. In step S1625, the communication unit 1602 transmits the command request report signal to the second radio power reception unit 1604. In step S1626, the second radio power receiver 1604 can return the report signal.

0171In step S1627, the control unit 1601 does not detect a load change. The communication unit 1602 transmits a notification signal in steps S1628 and S1629. The communication unit 1602 transmits the command signal to the first radio power receiver 1603 in step S1630, but cannot receive the report signal in step S1631 due to the removal of the first radio power receiver 1603. After this, the communication unit 1602 transmits the command signal to the second radio power receiver 1604 in step S1632, and the second radio power receiver 1604 transmits the report signal in step S1633.

0172The control unit 1601 does not detect the load change in step S1634. The communication unit 1602 transmits a notification signal in steps S1635 and S1636. The communication unit 1602 transmits the command signal to the first wireless power receiver 1603 in step S1637, but cannot receive the report signal in step S1638 due to the removal of the first wireless power receiver 1603. After that, the communication unit 1602 transmits the command signal to the second radio power receiver 1604 in step S1639, and the second radio power receiver 1604 transmits the report signal in step S1640.

0173For example, if the report signal cannot be received from the first wireless power receiver 1603 during the three superframe cycles, in step S1641, the control unit 1601 of the wireless power transmitter will use the first wireless power receiver. Determine that 1603 has been removed. After that, the control unit 1601 reduces the first charging power 1642.

0174The control unit 1601 executes load detection in step S1643, and transmits a notification signal in step S1644. The communication unit 1602 transmits the command signal only to the second radio power receiver 1604 in step S1645, and receives the report signal in step S1646 accordingly.

017517A and 17B are timing diagrams showing communication between a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention. In particular, FIGS. 17A and 17B are timing diagrams for a wireless power transmitter and a wireless power receiver that perform communication based on the BLE method.

0176Referring to FIG. 17A, the control unit 1750 of the wireless power transmitter checks the load change by applying the detected power 1702 in a predetermined period in step S1701. Further, the communication unit 1760 of the wireless power transmitter transmits a notification signal in a predetermined period in step S1703. Referring to FIG. 17A, control unit 1750 cannot detect a sudden change in load in step S1701.

0177In step S1704, user 1795 places the wireless power receiver on or near the wireless power transmitter.

0178In step S1707, the control unit 1750 further applies the detection power after the superframe cycle to detect a sudden change in load. The control unit 1750 applies a drive power (or registered power) Preg greater than the detection power 1702 by the value 1708 when the device is detected within the valid detection period. Here, the drive power may be power that can drive the control unit 1790 of the wireless power receiver.

0179The control unit 1790 of the wireless power receiver is driven (or powered on) in step S1705 and initializes the communication unit 1780 of the wireless power receiver in step S1706. The control unit 1750 determines the presence of the wireless power receiver based on the presence of the pulse initiated by the control unit 1790. The control unit 1750 can update the wireless power receiver whose existence is determined to the device control table.

0180For example, the device control table can be used for each session ID of the wireless power receiver, manufacturer ID, product ID, load characteristics, current characteristics, voltage characteristics, efficiency characteristics, current state, DC / DC converter of the wireless power receiver. Used to manage voltage at the front end of the wireless power receiver, voltage at the rear end of the DC / DC converter of the wireless power receiver, and current information at the rear end of the DC / DC converter of the wireless power receiver. To. Here, the current state is whether the wireless power receiver is in the standby state after charging is completed, the wireless power receiver is in the standby state due to insufficient charging power, or the wireless power receiver is charging in CV mode. This is information indicating whether the wireless power receiver is charging in CC mode.

0181Communication unit 1780 uses the second channel under the control of control unit 1790. Here, the second channel is a channel used by another wireless power transmitter 1770, which is different from the channel used by the communication unit 1760 of the wireless power transmitter. Therefore, the channel used by the communications unit 1760 is referred to as the first channel.

0182The order in which the control unit 1790 determines the search channel has already been set, and the initial search channel searched by the control unit 1790 can be randomly selected from the BLE channels.

0183In step S1710, the communication unit 1780 transmits the wireless power transmitter search signal on the second channel. The wireless power transmitter search signal can include device information of the wireless power receiver. For example, the device information of the wireless power receiver can include the ID of the wireless power receiver and the information about the device of the wireless power receiver. Information about the device of the wireless power receiver can include at least one of the manufacturer, serial number, protocol version, hardware version, and parameters related to charging the wireless power receiver.

0184In FIG. 17A, the three wireless power transmitters use the second channel, and each of the three wireless power transmitters 1770 responds to the wireless power transmitter search signal in steps S1711, S1714, and S1717. The wireless power transmitter search response signal can be transmitted to the communication unit 1780. The communication unit 1780 transmits a response signal or an Ack signal to the three radio power transmitters 1770 in steps S1713, S1716, and S1719.

0185The communication unit 1780 transmits the search signal in steps S1720, S1721, and S1722.

0186Control unit 1790 can change the search channel to the first channel. In step S1723, the communication unit 1780 transmits the search signal using the first channel. In step S1724, the communication unit 1760 receives the search signal, and the control unit 1750 stores the identification information of the wireless power receiver and the RSSI value. In step S1725, the control unit 1750 compares the stored RSSI with the RSSI threshold value, and in step S1726, determines whether or not to respond to the search signal.

0187If it is determined that the wireless power transmitter responds, the communication unit 1760 transmits a response signal in step S1728. Here, the response signal can include device information of the wireless power transmitter. The device information of the wireless power transmitter can include the ID of the wireless power transmitter.

0188The control unit 1790 controls the communication unit 1780 of the wireless power receiver in step S1732, and the communication unit 1780 transmits the identifier of the wireless power receiver and the device information in step S1729. The control unit 1750 receives the identifier and the device information in step S1730, and determines whether or not to subscribe the wireless power receiver in step S1731.

0189If the wireless power transmitter determines to subscribe to the wireless power receiver, the communication unit 1760 transmits a Connection signal to the communication unit 1780 in step S1733. The connection signal can include information such as the keep-alive period and the respective addresses of the radio power transmitter and the radio power receiver. In step S1734, the wireless power receiver grasps the ID and parameters of the wireless power transmitter based on the received connection signal.

0190According to another embodiment of the present invention, the communication unit 1760 can form a communication network by transmitting a connection signal in step S1733 immediately after receiving the search signal from the wireless power receiver in step S1723. ..

0191In step S1735, the communication unit 1760 transmits the parameter signal'TX parameter'of the wireless power transmitter to the communication unit 1780 of the wireless power receiver. The parameter signal of the wireless power transmitter is the identifier of the wireless power transmitter, the identifier of the wireless power receiver, the manufacturer, the serial number, the protocol version, the hardware version, the available charging power of the wireless power transmitter, and the current charge. It can include at least one of the number of wireless power receivers in it, the amount of power currently being charged, and the amount of surplus power available.

0192In step S1736, the communication unit 1780 transmits the parameter signal'RX parameter'of the wireless power receiver. The control unit 1750 receives the parameters of the wireless power receiver in step S1737, and determines whether or not to join the wireless power receiver to the wireless power network by analyzing the parameters of the wireless power receiver in step S1738. To do. In step S1739, the control unit 1750 generates a'permission information' signal indicating whether or not to permit the subscription, and in step S1740, the control unit 1750 transmits the subscription permission signal to the communication unit 1780 of the wireless power receiver. In steps S1741 to S1752, the subsequent charging process is the same as that of FIGS. 6A and 6B as described above, and thus a repeated detailed description thereof will be omitted.

0193Although the present invention has been described in detail with reference to specific embodiments, it is clear to those skilled in the art that various modifications can be made without departing from the scope and gist of the present invention. The scope of the present invention should not be limited to the above-described embodiments, but should be defined within the scope of the claims and equivalents.

0194100, 200, 503, 670, 1770 wireless power transmitter 110-1, 110-2, 110-n, 250 wireless power receivers 211 Power transmitter 212, 252, 501, 650, 690, 801, 804, 901, 904, 1101, 1601, 1750, 1790 Control unit 213, 253, 502, 660, 680, 802, 803, 902, 903, 1102, 1602, 1760, 1780 Communication section 251 Power receiver 254 Rectifier 255 DC / DC converter 256 switching unit 257 Charging unit 402, 406, 412, coil 404 FET element 405, 407, 410 capacitors 409 filter