Control of an electric machine

“METHOD OF CONTROL OF AN ELECTRIC MACHINE, SYSTEM OF

CONTROL FOR AN ELECTRIC MACHINE, BATTERY POWERED PRODUCT AND

VACUUM CLEANER"

The present invention relates to the control of an electric machine.

As the permanent magnet rotor of an electric machine rotates, it induces a counter electromotive force in a winding of the electric machine. As the rotor accelerates, the magnitude of the counter electromotive force increases. It is therefore becoming increasingly difficult to pass the current, and hence the energy, to the electric machine. As a result, control over the power of the electric machine becomes increasingly difficult.

In a first aspect, the present invention proposes a method of controlling an electric machine, the method comprising: sequentially exciting and freewheeling a winding of the electric machine, where the winding is excited by an excitation voltage and freewheeling at a freewheeling angle; and varying the freewheel angle 15 in response to changes in excitation voltage.

In the region of the falling counter-electromotive force, lower torque is obtained for a given level of current. Thus, by freewheeling the winding within this region, a more efficient electric machine can be obtained. Additionally, as the counter electromotive force in the winding drops, current peaks may arise if the excitation voltage exceeds the falling counter electromotive force. By freewheeling the winding within the falling counter-electromotive force region, current spikes can be avoided and thus a more uniform current waveform can be obtained.

By varying the freewheel angle in response to changes in excitation voltage, better control can be gained over both the efficiency and power of the electric machine. For example, by reducing the freewheel angle, the chain can be driven to the winding over a longer period to thereby increase power.

Preferably, the freewheeling angle is decreased in response to a reduction in excitation voltage. Consequently, as the excitation voltage decreases, the current is driven to the winding over a long period of time, thereby causing the decrease in excitation voltage. Thus, despite the drop in excitation voltage, the same or similar power can be obtained. Indeed, the method preferably comprises varying the freewheeling angle such that power of the electric machine is substantially constant over a range of excitation voltage. It should be understood that "substantially constant power" in this case means that the change in power 35 is not greater than +/- 5%.

The method advantageously comprises varying the freewheeling angle such that the efficiency of the electric machine (i.e. the ratio of output power to input power) is at least 75% over a range of excitation voltages. Thus, a relatively satisfactory efficiency is obtained over a range of

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2/35 excitement.

The range of excitation voltages may extend between a minimum voltage and a maximum voltage, with the minimum voltage being less than 80% of the maximum voltage. This then represents a relatively wide range of voltages over which it is possible to achieve constant power and / or satisfactory efficiency. Consequently, a battery module can be used as a source of excitation. Despite discharging the battery with use, it is nevertheless possible to achieve a constant power and / or satisfactory efficiency.

The method may include storing a control value power lookup table for a plurality of voltages, selecting a control value from the power lookup table according to the excitation voltage level, and freewheeling. winding for a period of time defined by the control value. This then simplifies the control of the electric machine.

Preferably each control value is a time that is proportional to the freewheeling angle. By employing a time for each control value, control of the electric machine 15 is considerably simplified.

The method advantageously comprises applying a speed correction value to the control value. The speed correction value then varies with both the speed of the electric machine and the level of excitation voltage. As the speed of the electric machine varies, the counter-electromotive force induced in the winding and, as yes, the power of the electric machine, also vary. By correcting the control value for speed, the effect of speed on voltage can be reduced. However, the optimal correction depends on the excitation voltage level. In particular, a larger correction would be ideal for a lower excitation voltage. By applying a speed correction value that varies with both the speed of the electric machine and the level of excitation voltage, better control over power is obtained.

The method may include storing a speed correction lookup table of speed correction values ​​for a plurality of speeds and a plurality of voltages, selecting from the speed lookup table a speed correction value according to speed. of the electric machine and the level of the excitation voltage30. This then simplifies the control of the electric machine.

Preferably, the method comprises varying the freewheel angle in response to changes in electric machine speed. Thus, better power control can be obtained for both changes in electric machine speed and excitation voltage. In fact, the preferred method comprises reducing the freewheel angle in response to the increase in electric machine speed. Consequently, as the speed of the electric machine increases, and thus the counter-electromotive force in the winding increases, the current is driven to the winding for a longer period. Thus, an equal or greater amount of energy is obtained.

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The method may comprise exciting the winding prior to zero crossing of the counter electromotive force in the winding. Thus, current can be driven to the winding at an earlier stage to provide more power.

Advantageously, each electric semicycle comprises a single drive period and a single freewheeling period. The winding is then excited during the drive period and freewheeled during the freewheeling period. Following the freewheel rotation period, the winding is switched.

In a second aspect, the present invention proposes a control system for an electric machine, the control system performing the method as described in any of the preceding paragraphs.

The preference control system comprises a position sensor, such as a Hall effect sensor, which emits a signal indicating the counter electromotive force in the winding. The control system then uses the output signal by the position sensor to control winding rotation and freewheeling and rotation.

The control system may comprise a current controller for limiting the current in the winding during excitation. This then prevents excessive buildup of currents in the winding, which would normally damage control system components or degauss the electrical machine magnets.

The control system may also comprise an inverter, a door trigger module and a drive controller. The drive controller then generates one or more control signals to control the winding excitation, and the door trigger module, in response to the control signals, controls the inverter switches.

In a third aspect, the present invention proposes a battery powered product comprising an electric machine and a control system as described in any one of the preceding paragraphs. The control system then excites the winding using the voltage of the battery module. The control system then varies the freewheeling angle in response to changes in battery module voltage.

In a fourth aspect, the present invention proposes a vacuum cleaner comprising an electric machine and a control system as described in any of the preceding 30 paragraphs.

The electric machine is preferably a permanent magnet motor, and more preferably a single phase permanent magnet motor.

In order that the present invention may be more readily understood, an embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a block diagram of a product according to the present invention;

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Figure 2 is a block diagram of the engine system of the product of Figure 1;

Figure 3 is a schematic diagram of the engine system;

Figure 4 is a schematic diagram of a motor system current controller;

Figure 5 illustrates motor system waveforms during a current control period;

Figure 6 illustrates motor system waveforms while operating at high speed;

Figure 7 is a graph of forward angle and freewheeling angle in contrast with excitation voltage; and

Figure 8 is a product of the present invention in the form of a vacuum cleaner.

The product 1 of Figure 1 comprises a power supply 2, a user interface 3, an accessory 4 and a motor system 5.

Power supply 2 comprises a battery module that provides 15 dc voltage for both accessory 4 and motor system 5. Power supply 2 is removable from product 1 so that product 1 can be used with modules different battery For purposes of this description, power supply 2 is both a 4 cell battery module providing 16.4 V DC power and a 6 cell battery module providing 24.6 V DC power. In addition, to provide a supply voltage, the power supply outputs an identifying signal that is specific to the type of battery module. The ID signal takes the form of a square wave signal that has a frequency that varies according to the type of battery module. In the present example, the 4 cell battery module outputs an ID signal that has a frequency of 25 Hz (20 ms pulse duration), while the 6 cell 25 battery module outputs an ID signal with a frequency of 50 Hz. (pulse duration 10 ms). The ID signal continues to be output from power supply 2 until the moment a fault is detected within power supply 2, for example low voltage or cell overtemperature. As described below, signal ID is used by motor system 5 to identify power supply type 2 and to periodically verify that power supply 2 is functioning correctly.

The user interface 3 comprises a power switch 6 and a power mode selector 7. The power switch 6 is used to turn the product on and off 1. In response to closing of the power switch 6, a closed circuit is formed between power supply 2 and each of accessory 4 and motor system 5. The 35 power mode selector 7 is used to control whether motor system 5 operates in high power mode or in a power mode. low power. When power mode selector 7 is closed, a logically high power module signal is output to the control system.

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5/35 engine 5.

Accessory 4 is removably connected to product 1. When connected to product 1 and product 1 is turned on, accessory 4 draws power from power supply 2 and sends an accessory signal to motor system 5. Instead of extracting power continuously 5 each time accessory 4 is connected and product 1 is turned on, accessory 4 may include a power switch (not shown), for example forming part of user interface 3. Accessory 4 then draws power and outputs the accessory signal only when the accessory's power switch is closed.

Referring now to Figures 2 and 3, the motor system 5 comprises an electric motor 10 and a control system 9.

Motor 8 comprises a bipolar permanent magnet rotor 17 which rotates relative to a stator 18 around which single phase winding 19 is wrapped. Stator 18 is in the shape of a “c”, which allows a high fill factor to be connected to winding 19. Thus, it is possible to reduce copper losses, thereby improving motor efficiency 8.

Control system 9 comprises a filter module 10, an inverter 11, a door trigger module 12, a current sensor 14, a controller 15 and a drive controller 16.

Filter module 10 connects power supply 2 of product 1 to inverter 11, and 20 comprises a pair of capacitors C1, C2 arranged in parallel. The filter module 10 acts to reduce the ripple in the electrical voltage connected to the inverter 11.

The inverter 11 comprises a full bridge of four Q1-Q4 power switches that connect power supply 2 to motor winding 19. Each Q1-Q4 power switch is a MOSFET, which offers fast switching and satisfactory long-term efficiency. of the power supply voltage strip 2. Other types of power switches could, however, be used, such as IGBTs or BJTs, particularly if the power supply voltage 2 exceeds the rated voltage XN of the MOSFETs. Each of the switches Q1-Q4 includes a return diode, which protects each switch from the voltage spikes of the counter electromotive force of motor 8 during switching.

When a first pair of switches Q1, Q4 is closed, winding 19 is excited in a first direction (left-to-right excitation), causing current to be driven around winding 19 in a first direction. When a second key pair Q2, Q3 is closed, winding 19 is excited in an opposite direction (right-to-left excitation), causing current to be conducted around winding 19 in an opposite direction. Thus, switches Q1-Q4 of inverter 11 can be controlled to switch current in winding 19.

In addition to driving the winding 19, the inverter 11 can be controlled to gi

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6/35 freewheeling winding 19. Freewheeling occurs when winding 19 is disconnected from the excitation voltage provided by power supply 2. This can occur by opening all switches Q1-Q4 in drive 11. However, the efficiency of motor system 5 is improved if one of the Q1-Q3 high side switches or Q2-Q4 low side switches are closed during freewheeling. By closing either the high side switches Q1, Q3 or the low side switches Q2, Q4, the current in winding 19 is able to recirculate through the keys instead of the less efficient return diodes. For the purposes of this disclosure, freewheeling is achieved by closing both low side switches Q2, Q4. However, it should be understood that freewheeling could also be achieved by closing the high side switches Q1, Q3 or by opening all keys Q1-Q4.

Gate trigger module 12 triggers opening and closing of Q1-Q4 of drive 11 in response to S1-S4 control signals received from drive controller 16. Gate trigger module 12 comprises four gate triggers 20-23, each door trigger activating a respective switch Q1-Q4 in response to a control signal S1-S4 of drive controller 16. Gate actuators 20, 22 responsible for high side switches Q1, Q3 are additionally triggered in response to an overcurrent signal received from current controller 15. In response to overcurrent signal, gate actuators 20, 22 open the switches on the high side Q1, Q3. The overcurrent signal takes precedence over control signals S1, S3 of drive controller 16 so that the high side switches Q1, Q3 are opened in response to the overcurrent signal, regardless of the state of control signals S1, S3. This level of control can be achieved by providing a NOR port on the high side door drivers 20, 22.

Table 1 summarizes the allowed states of switches Q1-Q4 in response to drive controller 16 S1-S4 control signals and current controller 15. Overcurrent signal due to the NOR port operating on the driver outputs high side door 20, 22 the high side switches Q1, Q3 are closed by the control signals S1, S3 which are logically low.

Control Signal Sign

Keys

Inverter Condition

Overcurrent

food

S1 S2 S3

XXX

S4

Q1

O"

Q2

Q3 Q4 Õ) U

0 11

0 1

High Side Switches Off

Left to right

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<td> 0</td><td> 1</td><td> 1</td><td> 0</td><td> 0</td><td> 0</td><td> 1</td><td> 1</td><td> 0</td><td>Excitement Right to Left</td>

<td> 0</td><td> 1</td><td> 1</td><td> 1</td><td> 1</td><td> 0</td><td> 1</td><td> 0</td><td> 1</td><td>Free wheel</td>

<td> 0</td><td> 1</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td>All switches off</td>

Table 1

Position sensor 13 is a Hall effect sensor that outputs a signal indicating the angular position of the permanent magnet rotor 17. The signal is a digital square wave, with each edge representing the angular position at which the rotor polarity changes. . The signal output by position sensor 13 is distributed to signal controller 16, which, in response, generates control signals S1-S4 that control inverter 11 and thus control the power distributed to motor 8.

During rotation, permanent magnet rotor 17 induces a counter electromotive force on motor winding 19. The polarity of the counter electromotive force changes with the polarity of rotor 17. Consequently, the position sensor signal provides not only a measure of the electrical position of the rotor 17, but also a measure of the counter electromotive force in the winding 19. Ideally, the position sensor 13 is aligned with respect to the rotor 17 so that the edges of the position sensor signal are synchronous or have a predetermined phase difference with the counter electromotive force zero crossings. However, after mounting motor system 5, there are tolerances associated with position sensor 13 alignment with motor 8. This, in turn, leads to a phase difference between the edges of the position sensor signal and the counter electromotive force zero crossings. As described in detail in the section entitled 'Fine Tuning Post-Mount', these tolerances are compensated for by using a position sensor offset that the drive controller 16 stores and subsequently uses to correct the position sensor signal.

Current sensor 14 comprises a one-way resistor R1 located on the negative rail of inverter 11. Electrical voltage through current sensor 14 therefore provides a measure of current in winding 19 when connected to power supply 2. Voltage current through the current sensor 14 is transmitted to the current controller 15.

Referring now to Figure 4, the current controller 15 comprises an input, an output, limit generator 24, a comparator 25 and an SR coupling 26.

The current controller output 15 is coupled to the current sensor output 14, and the current controller output 15 is coupled to the input of each of the high side door drivers 20, 22.

The limit generator 24 comprises a reference voltage input, a voltage limit switch. 12/51

8/35 PWM module 27, a nonvolatile memory device 28 and a filter 29. PWM module 27 employs a fixed frequency and a variable duty cycle that is set according to the scaling factor stored in device memory 28 PWM module 27 operates at the voltage at the reference input to provide a pulsed voltage signal, which is then smoothed out by filter 29 to provide a stepped threshold voltage.

Comparator 25 compares the electrical voltage at the current collector input 15 with the threshold voltage output by the limit generator 24. If the output voltage exceeds the threshold voltage, comparator 25 outputs a signal that engages SR 26. On In response, coupling SR 26 generates an overcurrent signal at the current controller output 15.

As noted above in Table 1, when the overcurrent signal is output from the current controller 15 (that is, when the overcurrent signal is logically high), the high side door triggers 20, 22 open the high side switches Q1. Q3. Accordingly, the current controller 15 disconnects winding 19 from the excitation voltage provided by power supply 2 when the current in winding 19 exceeds a limit value. As described in detail in the section entitled 'Post Assembly Fine Tuning', by employing a threshold voltage that is scaled according to a scaling factor, each individual motor system 5 can be finely tuned so that the effect of the Component tolerances over the current threshold can be compensated.

Current controller 15 also issues an overcurrent interrupt to drive controller 16. In the embodiment illustrated in Figure 4, the comparator output 25 is distributed to drive controller 16 as the overcurrent interrupt. However, the overcurrent signal emitted by the coupling 26 could also be distributed to the drive controller 16 as the overcurrent interrupt. In response to the overcurrent interruption, drive controller 16 executes an overcurrent routine. Drive controller 16 generates a control signal S2 or S4 which causes the remaining low side switches Q2 or Q4 to close so that winding 19 rotates freewheeling. Freewheeling continues indefinitely, for example 100 ps, ​​during which the current in winding 19 decays. After the predetermined time has elapsed, the drive controller 16 switches control signal S2 or S4 to open the newly closed low side switch Q2 or Q4 and output a coupling reset signal to current controller 15. Signal Resetting the coupling causes the coupling 26 of the current controller 15 to restart, thereby making the overcurrent signal low. Inverter 11 thus returns to the condition that existed before the overcurrent event occurred.

Figure 5 illustrates the winding current, position sensor signal, switch Q1-Q4, control signal S1-S4, overcurrent signal, and coupling reset signal waveforms during a half cycle typical. As can be seen, this petition 870190022792, of 11/03/2019, p. 13/51

9/35 of keys Q1-Q4 is the same before and after each overcurrent event.

The current in winding 19 may be reduced by the current controller 15 many times during an electric half cycle. As motor speed 8 increases, the counter electromotive force induced in winding 19 increases. Consequently, the number of overcurrent events decreases with motor speed. Over time, the speed of motor 8, and thus the magnitude of the counter electromotive force, is such that the current in winding 19 no longer reaches the threshold during each half cycle.

The current controller 15 ensures that the current within winding 19 does not exceed a threshold. Thus, excessive currents are prevented from accumulating in winding 19, which could consequently damage the keys Q1-Q4 of inverter 11 or degauss the rotor 17.

The drive controller 16 comprises a processor 30, a nonvolatile memory device 31, six signal inputs and five signal outputs.

Memory device 31 stores software instructions for execution by processor 30. In response to execution of instructions, processor 30 controls the operation of motor system 5. In particular, processor 30 generates control signals S1-S4 which control the keys Q1-Q4 of drive 11 and thus drives motor 8. Specific operation of drive controller 16 is described in more detail below. Memory device 31 also stores a plurality of power maps, a plurality of speed correction maps, and a plurality of position sensor offsets.

The six signal inputs are the power supply ID signal, the accessory signal, the power mode signal, the position sensor signal, the overcurrent interrupt and a voltage level signal.

The voltage level signal is derived from the power supply line, scaled by a potential splitter R2, R3 and filtered by a capacitor C3 to remove switching noise. The voltage level signal thus provides the drive controller 16 with a measure of the connection voltage supplied by the power supply 2. Due to the internal resistance of the power supply 2, the connection voltage is less than the circuit voltage 30. Open. For the 6 cell battery module, the maximum open circuit voltage is 24.6 V, which corresponds to a 23.0 V connection voltage. For the 4 cell battery module, the open circuit voltage The maximum voltage is 16.4 V, which corresponds to a 14.8 V connection voltage. In addition to this upper limit, drive controller 16 interrupts operation when the connection voltage falls below an undervoltage threshold. For the 35 6 cell battery module, the undervoltage threshold of the connection voltage is 16.8 V, which corresponds to an open circuit voltage of 19.0 V. For the 4 cell battery module, the The undervoltage threshold of the connection voltage is 11.2 V, which corresponds to a

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10/35 open circuit voltage 12.8 V. The current controller 16 therefore operates over a connection voltage range of 16.8 to 23.0 V for the 6 cell and 11.2 battery. at 14.8

V for the 4 cell battery.

The five output signals are the four S1-S4 control signals and the hitch reset signal. The four S1-S4 control signals are output to the door trigger module 12 which, in response, controls the opening and closing of inverter 11 keys Q1-Q4. More specifically, each S1-S4 control signal is output. to a respective door trigger 20-23. The coupling reset signal is output to the current controller 15.

Drive controller 16 generates control signals S1-S4 in response to signals received at inputs. As explained in more detail below, the synchronization of control signals S1-S4 is controlled so that motor 8 is driven at constant output power over a range of speeds. In addition, constant output power is maintained regardless of changes in the power supply voltage 2. Consequently, motor 8 is driven at constant output power as power supply 2 is discharged.

When the drive controller 16 generates a control signal, e.g. SI, to open a particular switch Q1 of inverter 11, there is a slight delay between generating the control signal SI and the physical opening of switch Q1. If drive controller 16 simultaneously generated a control signal S2 to close the other switch Q2 on the same arm of inverter 11, a short would potentially appear along inverter arm 11. This short, or “tripping” as it is commonly called, would damage switches Q1, Q2 on that arm of drive 11. Therefore, in order to avoid tripping, drive controller 16 employs a dead time (for example, 1 ps) between the generation of control signals for switches in the same arm of the inverter 11. It should therefore be understood that when referring to the text following winding excitation or freewheeling of winding 19, drive controller 16 employs a dead time between control signals. Dead time is preferably kept as short as possible to optimize engine performance.

Current controller 15 and drive controller 16 may form part of a single component microcontroller. A suitable candidate is the PIC16F690 microcontroller marketed by Microchip Technology Inc. This microcontroller has an internal comparator 25, a hitch 26, a PWM module 27, a nonvolatile memory device 28, 31, and a processor 30. The output pin of the PWM module 27 is fed to the input pin of the comparator 25 via filter 29, which is external to the microcontroller. Additionally, the comparator output 25 serves as an internal overcurrent interrupt, which is distributed to the drive controller processor 30

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16.

Current controller 15 and drive controller 16 together provide a form of hysteretic current control. In particular, current controller 15 generates an overcurrent signal engaged in response to an overcurrent event. The overcurrent signal causes the door trigger module 12 to open the high side switches Q1, Q3 of inverter 11 to thereby disconnect winding 19 from the connection voltage used for winding 19 excitation. Drive controller 16 then resets engagement 26 after a predetermined period of time has elapsed, during which time current in winding 19 decays.

Current control is achieved by combining hardware and software. In particular, the current controller hardware 15 monitors the current in winding 19 and generates an overcurrent signal in the event that the current exceeds a threshold. Drive controller software 16 restarts the current controller hardware 15 after a predetermined period of time.

By employing hardware to detect an overcurrent event, system control 9 responds relatively quickly to an overcurrent event. This is important to ensure that winding 19 is disconnected from the mains voltage as soon as possible after an overcurrent event. If instead software were employed to monitor an overcurrent event, there would be a significant delay between the overcurrent event and overcurrent signal generation, during which time the current in winding 19 may rise to a level that results. damage to components or rotor degaussing.

By employing software to reset the current controller hardware 15, the number of hardware components required to control the current in winding 19 may be reduced. Additionally, the drive controller software 16 is capable of controlling the predetermined period of time over which the current in the winding 19 decays. In the present embodiment, drive controller 16 resets engagement 26 of current controller 15 after a set time period (100 ps) has elapsed. However, drive controller 16 could also restart engagement 26 after a period of time that is adjusted according to motor speed 8. Thus, the level at which current decays with each reduction can be better controlled.

By reducing the current for a predetermined period of time, it is not necessary to monitor the current in winding 19 when disconnected from the supply voltage. Thus, current control can be achieved by using a one-way resistor. This not only reduces the cost of control system components 9, but also the energy dissipation by the one-way resistor is usually no higher.

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12/35 than 1% of the input energy.

The operation of motor system 5, and in particular of the drive controller

16 will be described now.

Startup mode

When power switch 6 is closed, power is distributed from power supply 2 to motor system 5, causing drive controller 16 to start. At startup, the drive controller 16 probes the inputs of the power supply ID signal, accessory signal, and power mode signal. Based on these three signals, the drive controller 16 selects a stored power map 10 stored in memory 31. As explained below, each power map stores control values ​​to drive motor 8 to a different output power. As can be seen from Table 2, drive controller 16 stores five different power maps. If power supply 2 is a 4-cell battery module (that is, if the frequency of the power supply ID signal is 25 Hz), then high power mode is not available 15 and the power mode signal is power is ignored.

<td colspan="3">Input Signals</td><td rowspan="2">Power Map</td>

<td>Power supply</td><td>Accessory</td><td>Power mode</td>

<td>50 Hz</td><td>Off</td><td>High</td><td>167 W</td>

<td>50 Hz</td><td>Switched on</td><td>High</td><td>136 W</td>

<td>50 Hz</td><td>On or Off</td><td>Low</td><td>96 W</td>

<td>25 Hz</td><td>Off</td><td>Ignored</td><td>107 W</td>

<td>25 Hz</td><td>Switched on</td><td>Ignored</td><td>83 W</td>

Table 2

The power map selected by drive controller 16 is subsequently used by drive controller 16 to generate S1S4 control signals when operating in "High Speed ​​Acceleration Mode" and "Normal Operation Mode 20".

While drive controller 16 is on, drive controller 16 periodically probes (e.g., every 8 ms) the power supply ID signal, accessory signal, and power mode signal. If the power supply ID signal is constantly high or low instead of synchronized, this indicates a problem with power supply 2; drive controller 16 then opens all keys Q1-Q4 and terminates. If the accessory signal or the power mode signal changes, drive controller 16 selects a new power map.

In power map selection, drive controller 16 goes into

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13/35 Resynchronization ”.

Resync Mode

Drive controller 16 determines motor speed 8 and selects the operating mode according to the given speed. Motor speed 8 is obtained by measuring the time interval between two edges of the position sensor signal, ie the pulse duration. If the drive controller 16 fails to detect two or more edges within a predetermined time (e.g. 26 ms), motor speed 8 is considered to be no greater than 1 krpm; drive controller 16 then enters “Stationary Mode”. Otherwise, drive controller 16 waits until an additional edge of the position sensor signal is detected. Drive controller 16 then averages the time interval along the three edges to provide a more accurate determination of motor speed. If the time interval between two edges is greater than 1875 ps, motor speed 8 is determined to be between 1 and 16 krpm; drive controller 16 then enters “Low Speed ​​Acceleration Mode”. If the time range is between 500 and 1875 ps, motor speed 8 is determined to be between 16 and 60 krpm, and drive controller 16 enters “High Speed ​​Acceleration Mode”. Otherwise, motor speed 8 is determined to be at least 60 krpm and drive controller 16 enters “Normal Operation Mode”. Table 3 details the time intervals, speeds and modes of operation.

<td rowspan="6">Mod</td><td>Range (ps)</td><td>Speed ​​(krpm)</td><td>Mode</td>

<td>t&gt; 26000</td><td>ω 1</td><td>Stationary</td>

<td>1875 &lt;t &lt;26000</td><td>1 &lt;ω &lt;16</td><td>Low Speed ​​Acceleration</td>

<td>500 &lt;t &lt;1875</td><td>16 &lt;ω &lt;60</td><td>High Speed ​​Acceleration</td>

<td>t &lt;500</td><td>ω&gt; 60</td><td>Normal operation</td>

<td>the Stationary</td><td colspan="2">ade &lt;1 krpm)</td>

Drive controller 16 excites winding 19 for a predetermined time, for example 25 ms. During this time, drive controller 16 switches winding 19 (i.e. reverses excitation direction) in sync with the edges of the position sensor signal. The initial excitation period should make the rotor 17 rotate. If, during this predetermined time, both edges of the position sensor signal are detected, drive controller 16 enters “Low Speed ​​Acceleration Mode”. Otherwise, drive controller 16 opens all keys Q1-Q4 and writes a “Failed to Start” error in device memory 31.

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Low Speed ​​Acceleration Mode (1 krpm &lt;speed &lt;16krpm)

Drive controller 16 excites winding 19 in sync with the edges of the position sensor signal. Synchronous excitation continues until motor speed 8 reaches 16 krpm, as determined by the time interval between the rising edges, after which the drive controller 16 enters “High Speed ​​Acceleration Mode”. If motor 8 fails to reach 16 krpm within a predetermined time, for example 2.5 s, drive controller 16 opens all switches Q1-Q4 and writes a “Low Speed” error to device memory 31.

High Speed ​​Acceleration Mode (16 &lt;speed &lt;60 krpm)

During high-speed acceleration, drive controller 16 sequentially excites and freewheels winding 19. More particularly, each electric semicycle comprises a single drive period during which winding 19 is excited, followed by a single time period. freewheeling, during which winding 19 is freewheeled. During the drive period, the current in winding 19 may be reduced by the current controller 15. Therefore, winding 19 may additionally be freewheeled at short intervals (e.g. 100 ps) within the drive period. However, any freewheel spinning that occurs within the drive period is different from what occurs in the freewheeling period. After each freewheeling period, winding 19 is switched (ie the direction of excitation is reversed).

Drive controller 16 excites winding 19 prior to the edges of the position sense signal, and thus before zero passes of the counter electromotive force in winding 19. In addition, drive controller 16 excites winding 19 before position sensor signal edges for a period of time 25 that remains fixed as motor 8 accelerates from 16 krpm to 60 krpm. Drive controller 16 also spins winding 19 for a period of time that remains fixed as the motor accelerates from 16 krpm to 60 krpm.

As described in more detail below, each power map (see Table 2) comprises a free time and lead times lookup table for a plurality of voltage levels. Upon entering “High Speed ​​Acceleration Mode” the drive controller 16 probes the voltage level signal to obtain the excitation voltage, ie the connection voltage supplied by the power supply 2. Drive controller 16 then selects from the power map the lead time T_ADV and the freewheeling time T_FREE corresponding to the excitation voltage. By way of example, 35 if the selected power map is 167 W (see Table 2) and the voltage level signal indicates that the excitation voltage is 22.7 V, drive controller 16 selects from the map 34 ps feed time and 128 ps freewheeling time (see

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Table 4).

Winding 19 is excited and freewheeled as follows. Upon sensing an edge of the position sensor signal, drive controller 16 continues to drive winding 19 for the time period T_DRIVE_OFF. T_DRIVE_OFF is calculated from semicycle time T_HALF_CYCLE, lead time T_DAV, and freewheel time T_FREE:

T_DRIVE_OFF = T_HALF_CYCLE - T_DAV - T_FREE

The half-cycle time, T_HALF_CYCLE, is the time interval between two successive weddings of the position sensor signal. Advance time, T_DAV, and freewheeling time, T_FREE, are the times obtained from the power map.

After the T_DRIVE_OFF period, drive controller 16 spins winding 19 during the T_FREE period, after which drive controller 16 switches winding 19. The end result is that drive controller 16 turns winding 19 before the next edge of the position sensor signal by the lead time, T_DAV.

Figure 6 illustrates the winding current, position sensor signal, excitation voltage, and control signals S1-S4 waveforms over some semicycles.

As motor 8 accelerates, counter electromotive force 19 increases. Therefore, it is becoming increasingly difficult to pass the current, and hence the energy, to the winding 19 of the motor 8. If the winding 19 were excited in sync with the edges of the position signal sensor, and thus , in sync with the counter-electromotive force zero crossings, would reach a speed at which it would no longer be possible to conduct more energy to the winding 19. By exciting the winding 19 before the edges of the position sensor signal 25, and thus before the zero crossings of the counter electromotive force, current is fed to the winding 19 in the previous stage. As a result, more energy is led to the winding 19.

As the counter electromotive force in winding 19 increases with motor speed, the electric angle at which excitation occurs in advance of the counter electromotive force preferably increases motor speed, i.e. the feed angle at 60 krpm. is preferably greater than 16 krpm. By excitation of winding 19 before the counter electromotive force for a fixed period of time, T_ADV, the corresponding electrical angle, A_ADV, increases with motor speed. In particular, the feed angle, A_ADV, increases proportionally with the engine speed:

A ADV = T ADV * ω / 60 * 260 ° where ω is the motor speed in rpm. As a result, as motor 8 accelerates, current is fed to winding 19 at an increasingly increasing stage. Page 8 870190022792, 11/03/2019, p. 20/51

16/35 later. As a result, more energy is led to the winding 19.

By employing a fixed feed time, T_ADV, there is no need for drive controller 16 to perform dynamic calculations as to which feed angle should be used as motor 8 accelerates. This then greatly minimizes the number of instructions that need to be executed by processor 30 of drive controller 16, and thus a cheaper processor 30 can be used.

Drive controller 16 spins winding 19 at a time when the counter electromotive force in winding 19 is dropping. As the counter electromotive force 19 drops, less torque is obtained for a given current level. Thus, by freewheeling the winding 19 within this region, a more efficient motor system 5 can be obtained. Additionally, the counter electromotive force in winding 19 may exceed that of the excitation voltage. Consequently, as the counter electromotive force in winding 19 drops, current peaks may arise if the excitation voltage suddenly exceeds that of the falling counter electromotive force. By freewheeling rotation of winding 19 within the falling counter-electromotive force region, current surges are avoided and thus a more uniform current waveform is obtained.

Drive controller 16 continues to drive sequentially and freewheel winding 19 in the manner described above until motor speed 8 reaches 60 krpm. During this time, the freewheeling advance and turn times, T_ADV and T_FREE, are fixed. At 60 krpm, drive controller 16 enters “Normal Operation Mode”. If the motor fails to reach 60 krpm within a predetermined time, for example 2.5 s, drive controller 16 opens all keys Q1-Q4 and writes a “Low Speed” error to device memory.

Normal Operation Mode (speed at 60 krpm)

As in “High Speed ​​Acceleration Mode”, drive controller 16 sequentially excites and spins winding 19. Each electric semicycle therefore continues to comprise a single drive period followed by a single freewheel period. . Again, the winding 19 is excited before the edges of the position sensor signal and thus before the counter electromotive force zero passes. However, in contrast to the “High Speed ​​Acceleration Mode” in which fixed times are employed for lead time and freewheel time, drive controller 16 now varies lead time and wheel time. free so as to obtain a constant output power.

Drive controller 16 excites winding 19 before the edges of the position sensor signal by an electric angle, A_ADV, and freewheels winding 19 along the electrical angle, A FREE. The drive controller 16 varies as much as possible. 870190022792, 11/03/2019, p. 21/51

17/35 feedrate, A_ADV, for freewheeling angle, A_FREE, in response to changes in excitation voltage (ie power supply 2 connection voltage) and motor speed 8 to obtain a constant output power.

Power supply 2 is a battery module and therefore the excitation voltage decreases as the battery module is discharged with use. If the electrical angles at which winding 19 is excited and freewheeled are fixed, the input power, and thus the output power of the motor system 5, would decrease as the power supply 2 discharged. Thus, in order to maintain a constant input power, drive controller 16 varies the feed angle, A_ADV, and freewheel angle, A_FREE, in response to changes in excitation voltage. In particular, the feed angle, A_ADV, increases and the freewheel angle, A_FREE, decreases with reduction of excitation voltage. By increasing the feed angle, A_ADV, the current is triggered in winding 19 at an earlier stage. By decreasing the freewheeling angle, A_FREE, winding 19 is excited for a long period along the semicycle. The end result is that, in response to a drop in excitation voltage, more current is fed to the winding 19 along the semicycle and thus the constant output power is maintained.

Figure 7 illustrates the variation in feed angle and freewheeling angle for constant output power over a voltage range of 16.8 to 23.0 V. As noted above, this voltage range corresponds to DC link voltage of the 6-cell battery module. Below 16.8 V, it is difficult to conduct sufficient current to winding 19 to maintain constant output power without potentially demagnetizing rotor 17. Additionally, the voltage of the 6-cell battery module decreases significantly by 16.8 V. Therefore, if the DC link voltage drops below 16.8 V, the drive controller 16 opens all switches Q1-Q4. and it ends. A similar pattern is observed for the 4-cell battery module over the 11.2 to 14.8 V operating range; again, the drive controller opens all Q1-Q4 switches and terminates when the DC link voltage drop below 11.2 V.

The variation in feed angle and freewheel angle is stored by drive controller 16 as a power map. Each power map comprises a look-up table storing a lead time and a freewheeling time for each of a plurality of stress levels. As described in more detail below, the drive controller 16 monitors the voltage level signal and selects from the power map a corresponding lead time and freewheeling time from the power map. Drive controller 16 then uses the freewheeling advance and freewheeling times obtained from the power map to control winding excitation and freewheeling 19. Therefore, constant output power is obtained for

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18/35 motor system 5, regardless of changes in excitation voltage. Table 4 illustrates a section of the 167 W power map.

<td>Tension of DC connection (V)</td><td>Advance Time (MS)</td><td>Freewheel Turning Time (ps)</td>

<td> 16,8</td><td> 91</td><td> 51,2</td>

<td> 16,9</td><td> 90</td><td> 52,8</td>

<td> 17,0</td><td> 89</td><td> 56,0</td>

<td> 17,1</td><td> 88</td><td> 57,6</td>

<td></td><td></td><td></td>

<td> 22,7</td><td> 34</td><td> 128,0</td>

<td> 22,8</td><td> 33</td><td> 128,0</td>

<td> 22,9</td><td> 32</td><td> 129,6</td>

<td> 23,0</td><td> 31</td><td> 129,6</td>

<td>Advance Angle (°)</td><td>Freewheel Turn Angle (°)</td><td>Power of Input (W)</td><td>Power Output (W)</td>

<td> 54,1</td><td> 30,4</td><td> 189,4</td><td> 166,5</td>

<td> 53,5</td><td> 31,4</td><td> 189,9</td><td> 167,0</td>

<td> 52,3</td><td> 33,3</td><td> 189,7</td><td> 166,9</td>

<td> 51,1</td><td> 34,2</td><td> 189,5</td><td> 166,8</td>

<td></td><td></td><td></td><td></td>

<td> 20,2</td><td> 76,0</td><td> 187,5</td><td> 166,8</td>

<td> 19,6</td><td> 76,0</td><td> 187,3</td><td> 167,5</td>

<td> 19,0</td><td> 77,0</td><td> 187,6</td><td> 166,9</td>

<td> 18,4</td><td> 77,0</td><td> 187,3</td><td> 166,6</td>

Only the left part of the table is stored by the drive controller 16 as the 167 W power map. The right part has been included for the purposes of this description and is not part of the power map. As can be seen from the table, the 167 W power map stores lead times and freewheeling times that deliver a constant output power of 167 W. DC link voltage is sampled at a resolution of 0.1 V. The power map is thus reasonably small, without being so small as to adversely affect motor system performance 5. Obviously, depending on the size of the drive controller 16 memory device 31, the power map resolution can be increased or decreased.

It should be noted that the power map stores lead times and freewheel turn times rather than feed angles and freewheel turn angles. Drive controller 16 uses timers to generate S1-S4 control signals that excite and freewheel winding 19. Therefore, by storing freewheeling and turning times instead of angles, the instructions executed by the controller drive systems 16 are greatly simplified. However, the power map could alternatively store feed angles and freewheeling angles, which the drive controller 16 then uses to control the excitation and freewheeling of winding 19.

Each angle of freewheeling and turning has a corresponding time depending on motor speed 8. For each power map, drive controller 16 drives motor 8 within a particular operating speed range. Here

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19/35 of the operating speed range has a nominal speed, which is used to calculate lead times and freewheeling times:

T ADV = (A ADV / 360 °) * 60 / © nominal

TFREE = (AFREE / 360 °) * 60 / co_noominai

Where nominal © is the nominal speed in rmp. Table 5 lists the operating speed ranges and nominal speeds for the various power maps.

<td>Power Map</td><td>Minimum Speed ​​(krpm)</td><td>Max Speed ​​(krpm)</td><td>Rated Speed ​​(krpm)</td>

<td>167 W</td><td> 89,5</td><td> 104,5</td><td> 99</td>

<td>136 W</td><td> 84,5</td><td> 98,5</td><td> 93.5</td>

<td>96 W</td><td> 75</td><td> 87,5</td><td> 83</td>

<td>107 W</td><td> 77,5</td><td> 91</td><td> 86</td>

<td>83 W</td><td> 71,5</td><td> 83,5</td><td> 79</td>

Table 5

Each power map stores lead times and freewheeling times for engine 8 rotating at rated speed. So, for example, the 167 W power map winding stores freewheeling forward and spin times that achieve constant output power when motor 8 is spinning at a speed of 99 krpm. When motor 8 rotates at speeds above or below rated speed, drive controller 16 applies a speed correction value to each of the lead time and idle run time, as described in more detail below. .

As mentioned above in the Startup ”section, drive controller 16 stores five power maps and selects one of the power maps according to the condition of the power supply ID signal, accessory signal, and power mode signal. The output power of motor 8 is thus determined by the type of power supply 2 that is connected to product 1, whether accessory 4 is plugged in or not, and based on whether the user has selected a high power mode or a low power mode.

As can be seen from Table 2, a different power map is selected according to whether a 6 cell battery module or a 4 cell battery module is connected to product 1. Once the 4 cell battery module has a lower charge capacity, product 1 would have a shorter operating time if the same power map were selected for both 6 cell and 4 cell battery modules. By selecting the power map that distributes lower output power, a similar operating time for the 4 cell battery module can be obtained at the expense of output power.

When the 6-cell battery module is connected to product 1, the user is assigned to the product. 1 870190022792, 11/03/2019, p. 24/51

You can control the output power of motor 8 via power selector 7. As can be seen from Table 2, a power map distributing 96 W output power is selected in response to a mode signal. power which is logically low, that is when the user selects the low power mode. An upper voltage map distributing either 167 W (with the accessory off) or 136 W (with the accessory on) is then selected in response to a power mode signal that is logically high, ie when the user selects a High power mode.

Since accessory 4 draws power from power supply 2, power supply 2 will discharge faster if the same power map is selected10. In addition, excessive current can be drawn from power supply 2 to power both accessory 4 and motor 8. Therefore, in response to the accessory signal, drive controller 16 selects a power map that distributes power of bottom output, see Table 2. Accordingly, power supply 2 is protected from excessive current extraction and a similar operating time for product 1 can be obtained at the expense of output power.

Power maps therefore provide a convenient means of controlling the output power of motor system 5 in response to one or more input signals.

As noted above, each power map stores lead times and freewheel times that reach constant output power when motor 8 operates at a nominal speed. However, as motor speed 8 varies, the counter electromotive force in winding 19 also varies. Accordingly, if the angles at which winding 19 is excited and freewheeled are fixed, the output power of motor 8 would vary with motor speed. In particular, the output power of motor 8 would decrease as motor speed increases. In order to maintain constant output power throughout each operating speed range, drive controller 16 varies the feed angle and freewheel angle in response to changes in motor speed 8.

Drive controller 16 applies a speed correction value to each of the feed angle and the freewheel angle. As engine speed increases, counter electromotive force 19 increases. Consequently, in order to keep the output power constant, a speed correction value is applied to the feed angle, which increases the feed angle. In addition, a speed correction value is applied to the freewheel angle, which decreases the freewheel angle. Therefore, the current is conducted to winding 19 at an earlier stage and for a longer period for every half-cycle. As a result, constant output power can be achieved despite the increase in counter electromotive force.

The velocity correction values ​​that are applied to the feed angle and

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21/35 freewheeling angle depends not only on motor speed 8, but also on the level of the excitation voltage, ie the DC link voltage provided by the power supply 2. As the excitation voltage decreases , a specific speed correction value has a minor useful effect on motor output power 8. Thus, 5 in order to keep the output power constant, the speed correction values ​​increase in magnitude with the reduction of the excitation voltage.

For each power map, drive controller 16 stores two speed correction maps: one forward speed correction map and one freewheel speed correction map. Each velocity correction map comprises a look-up table that stores a velocity correction value for each of a plurality of speeds and a plurality of voltage levels. Since the power map stores lead times and freewheel times, speed correction values ​​are expressed as times. However, if each power map alternatively stores feed angles and freewheel angles, speed correction maps then store speed correction values ​​expressed as angles. Tables 6 and 7 list, respectively, the forward speed correction map and the freewheeling speed correction map for the 167 W power map.

<td rowspan="2">Speed ​​(rpm)</td><td colspan="8">DC Link Voltage (V)</td>

<td> 16,8</td><td> 17,6</td><td> 18,4</td><td> 19,2</td><td> 20,0</td><td> 20,8</td><td> 21,6</td><td> 22,2</td>

<td> 89500</td><td> -8,2</td><td> -6,9</td><td> -5,7</td><td> -4,7</td><td> -4,5</td><td> -4,1</td><td> -3,8</td><td> -3,5</td>

<td> 90361</td><td> -7,4</td><td> -6,1</td><td> -5,1</td><td> -4,2</td><td> -3,9</td><td> -3,7</td><td> -3,5</td><td> -3,3</td>

<td> 91241</td><td> -6,5</td><td> -5,4</td><td> -4,4</td><td> -3,7</td><td> -3,5</td><td> -3,3</td><td> -3,1</td><td> -2,8</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 99000</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 102180</td><td> 2,1</td><td> 1,7</td><td> 1,4</td><td> 1,2</td><td> 1,1</td><td> 1,2</td><td> 1,1</td><td> 1,0</td>

<td> 103305</td><td> 3,0</td><td> 2,4</td><td> 2,0</td><td> 1,6</td><td> 1,6</td><td> 1,6</td><td> 1,5</td><td> 1,4</td>

<td> 104500</td><td> 3,9</td><td> 3,2</td><td> 2,6</td><td> 2,1</td><td> 2,0</td><td> 2,0</td><td> 1,9</td><td> 1,7</td>

Table 6

<td rowspan="2">Speed ​​(rpm)</td><td colspan="8">DC Link Voltage (V)</td>

<td> 16,8</td><td> 17,6</td><td> 18,4</td><td> 19,2</td><td> 20,0</td><td> 20,8</td><td> 21,6</td><td> 22,2</td>

<td> 89500</td><td> 24,9</td><td> 23,8</td><td> 10,9</td><td> 5,4</td><td> 3,4</td><td> 2,0</td><td> 0,6</td><td> 0,6</td>

<td> 90361</td><td> 22,1</td><td> 21,2</td><td> 7,7</td><td> 4,9</td><td> 3,0</td><td> 1,8</td><td> 0,6</td><td> 0,3</td>

<td> 91241</td><td> 19,4</td><td> 18,1</td><td> 5,1</td><td> 4,3</td><td> 2,7</td><td> 1,6</td><td> 0,5</td><td> 0,3</td>

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22/35

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 99000</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td> 102180</td><td> -6,6</td><td> -7,0</td><td> -5,7</td><td> -1,2</td><td> -1,0</td><td> -0,6</td><td> -0,2</td><td> -0,4</td>

<td> 103305</td><td> -9,4</td><td> -8,8</td><td> -7,1</td><td> -2,1</td><td> -1,3</td><td> -0,8</td><td> -0,3</td><td> -0,1</td>

<td> 104500</td><td> -12,2</td><td> -11,5</td><td> -8,1</td><td> -2,6</td><td> -1,6</td><td> -0,9</td><td> -0,3</td><td> -0,1</td>

Table 7

It can be seen from the speed correction maps that as the engine speed increases, the lead time is corrected by an amount that increases the lead time, and freewheel time is corrected by an amount that decreases freewheeling time. In addition, as the excitation voltage decreases, the amount by which the lead time and freewheeling time are corrected increases. Since each power map stores a lead time and a freewheeling time for a rated speed, the speed correction values ​​at rated speed are zero.

When selecting values ​​from speed and power correction maps, drive controller 16 rounds down the excitation voltage and motor speed 8 to the nearest entry in the lookup table.

Drive controller 16 drives winding 19 in a manner similar to that described above for the "High Speed ​​Acceleration Mode". In particular, upon sensing an edge of the position sensor signal, drive controller 16 continues to drive winding 19 during the TDRIVEOFF time period:

T_DRIVE_OFF = T_HALF_CYCLE - TADV - T_FREE

Again, the semicycle time, T_HALF_CYCLE, is the time interval between two successive edges of the position sensor signal. After the T_DRIVE_OFF period, drive controller 16 spins winding 19 during the T_FREE period, after which drive controller 16 switches winding 19. The end result is that drive controller 16 turns winding 19 before the next edge of the position sensor signal by the lead time, T_ADV.

Again, Figure 6 illustrates the winding current, position sensor signal, excitation voltage, and control signals S1-S4 waveforms after some semicycles.

The drive controller 16 periodically monitors (for example, each semicycle) the voltage level signal to obtain the excitation voltage. The lead time, T ADV, and the freewheeling time, T FREE, are then obtained by selecting from the relevant power map the lead time and the freewheeling time corresponding to the excitation voltage. The selected times of the power map are then corrected by the values

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23/35 speed correction selected from speed correction maps. So, for example, if the excitation voltage supplied by the power supply is 17.0 V (as determined by the voltage level signal) and the motor speed is 103 krpm (as determined by the semi-cycle time), the drive controller 16 selects a feed time of 89 ps and a freewheeling time of 56 ps from the 167 W power map (Table 4). Drive controller 16 then corrects the lead time by 2.09 ps as determined by the feed rate correction map (Table 6) and corrects the freewheel time by -6.64 ps as determined. by the freewheeling speed correction map (Table 7). Accordingly, drive controller 16 uses a feed time, T_DAV, of 91.09 ps, and a freewheeling time, T_FREE, of 49.36 ps.

Drive controller 16 therefore drives motor 8 at constant output power over a range of drive voltages and motor speeds. Thus, a constant output power is obtained as the power supply 2 is discharged, and the motor 8 carries different loads.

The use of lookup tables storing lead times and free time, as well as speed correction values, greatly simplifies the calculations performed by drive controller processor 30. Consequently, a relatively inexpensive processor 30 can be used to generate the control signal S1-S4 which excites and freewheels winding 19.

Position Sensor Error

Electromagnetic noise can cause position sensor 13 to generate false edges. If detected by drive controller 16, these false edges would cause drive controller 16 to drive winding 19 at incorrect times. Not only would this effect adversely affect motor system performance 5, but it could also result in excessive winding current 19 that could potentially damage keys Q2, Q4 or degauss the rotor 17. The drive controller 16 therefore employs measures to minimize the possibility of detecting false edges. The specific measures employed depend on the mode of operation.

When operating in “Low Speed ​​Acceleration Mode”, drive controller 16 excites winding 19 in sync with the edges of the position sensor signal. After switching, the drive controller 16 ignores the position sensor signal for a predetermined time, for example 250 ps. Therefore, any false edges that fall within this period are ignored.

When operating in “High Speed ​​Acceleration Mode” and “Normal Operation Mode”, drive controller 16 employs a position sensor window. Any edges of the position sensor signal that are generated outside this window are

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24/35 ignored by drive controller 16. If no edge is detected within the position sensor window, drive controller 16 opens all keys for a predetermined time (eg 50 ms) and enters “Resync Mode "

Since the winding 19 is excited before the edges of the position sensor signal, each signal edge is expected to occur at a time T_ADV after excitation. The position sensor window therefore starts on excitation and has a length greater than the lead time, T_ADV. Preferably, the position sensor window has a length corresponding to the sum of the lead time, T_ADV, and a quarter of the half-cycle time, T_HALF_CYCLE. This then provides a sufficiently narrow window 10 in which the next edge of the position sensor signal can be reliably detected. Of course, the position sensor window may be larger or smaller. However, as the position window decreases in size, the risk of losing an authentic signal edge increases, especially if there is significant imbalance in the position sensor signal activity cycle (see below). As the position window increases, the risk of detecting a false edge increases. Thus, the position sensor preferably is not greater than the sum of the lead time and half of the semi-cycle time.

In addition to generating false edges, the position sensor signal activity cycle may not be balanced. If the half-cycle time is determined from the interval between a single pair of successive edges (ie, a single pulse) of the position sensor signal, any imbalance in the duty cycle will result in an incorrect half-cycle time.

Since semi-cycle time is used not only to control when winding 19 is excited, but also to apply speed correction values, any error in semi-cycle time can adversely affect engine system performance. 5 . Thus, in order to reduce the error in the semicycle time, the drive controller 16 obtains the semicycle time by averaging the interval between successive edges for a plurality of position sensor signal pulses. For example, drive controller 16 can obtain the semi-cycle time by averaging the interval between successive edges for the four previous pulses of the position sensor signal. By averaging the interval between successive edges for a plurality of pulses, any change in semicycle time is significantly reduced.

In addition, drive controller 16 excites winding 19 in response to, but not both, rising edges or falling edges of the position sensor signal. Drive controller 16 then calculates drive times for both halves of each electrical cycle in response to a single edge, that is rising or falling, but not both. In particular, drive controller 16 calculates drive bypass time for the first semicycle, T_DRIVE_OFF, as described

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25/35 above, that is, using semi-cycle time, lead time and freewheeling time. The drive deviation time for the second semicycle, T_DRIVE_OFF_2, is then obtained by adding the semicycle deviation time to the drive deviation time of the first semicycle:

T_DRIVE_OFF_1 = T_HALF_CYCLE - T_ADV - T_FREE

TDRIVEOFF2 = T_DRIVE_OFF_1 + T_HALF_CYCLE

Since drive controller 16 acts in response to only a single edge, drive controller 16 is less sensitive to any imbalance in the position sensor signal activity cycle. Therefore, engine system performance 10 5 is not adversely affected by the duty cycle imbalance.

Fine Tuning Post-Assembly

After mounting the motor system 5, there are tolerances that may adversely affect the performance of motor system 5. Consequently, after mounting, motor system 5 is fine tuned.

The current controller 15 ensures that the current within winding 19 does not exceed a threshold. This then prevents degaussing of rotor 17 and protects keys Q1-Q4 of drive 11. However, various component tolerances affect the current level at which current controller 15 generates the overcurrent signal. For example, current sensor 14 has a tolerance on the resistance of sense resistor R1, and therefore the voltage distributed to the input of current controller 15 has a variation. In addition, there is a tolerance on the voltage level of the reference voltage used by the current controller 15. In addition, there is a tolerance on the comparator input bypass voltage 25 and the input leakage current. Overall, the current threshold tolerance stack can reach ± ​​20%. This tolerance is too large to ensure that motor 8 operates 25 efficiently without potentially demagnetizing rotor 17 or damaging drive Q1-Q4 switches. Therefore, after mounting control system 9, current controller 15 receives fine-tuning to rectify component tolerances.

The output of inverter 11 is connected to an inductive load that resembles motor 8. An external current sensor accurately measures current through the inductive load. PWM module 27 is loaded with a relatively low duty cycle, and the inductive load is excited. As the current in the inductive load increases, the current controller 15 generates the overcurrent signal to reduce the current. Since the PWM module 27 is loaded with a relatively low duty cycle, the current is reduced below the ideal current threshold. The external current sensor accurately measures the current level at which the overcurrent signal was generated. The duty cycle of module PWM 27 is then increased and the process is repeated. Finally, the current controller 15 generates the overcurrent signal at an ideal current threshold. At that time, the

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The duty cycle value is written to the memory device 28 of the current controller 15 as a scaling factor.

The current controller 15, therefore, is finely tuned such that an overcurrent signal is generated whenever the current in winding 19 exceeds a well-defined threshold 5, regardless of component tolerances. By employing an accurate external current sensor and fine resolution for the PWM duty cycle, the threshold at which the overcurrent signal is generated can be precisely controlled. Thus, tight control over current in winding 19 is obtained without the need for expensive and high tolerance components. In fact, the use of a PWM 27 10 module is a simple and effective means for generating a threshold voltage.

After motor system 5 has been mounted, there is a tolerance associated with position sensor 13 alignment with motor 8. This tolerance results in a phase difference between the detected position of rotor 17 as provided by the position sensor signal. , and the actual position of the rotor 17. This in turn translates into a phase difference 15 between the edges of the position sensor signal and the zero-passes of the counter electromotive force in the winding 19. After motor 8 is mounted, motor 8 is driven at a speed of 49.5 krpm. This speed corresponds to half the nominal speed (ie 99 krpm) for the 167 W power map. The power to motor 8 is then interrupted and the counter electromotive force in winding 19 is measured and compared to the 20 edges. position sensor signal. The time difference between the position sensor signal edges and the counter electromotive force zero passes gives a measure of the phase difference at 49.5 krpm. The time difference at 49.5 krpm is then scaled to the rated power map speed and stored in the drive controller memory device 30 as a position sensor offset, 25 T_POS_OFFSET. So, for example, the time difference at 49.5 krpm is doubled to give the position sensor offset for the 167 W power map, while the time difference is multiplied by 79.0 / 49.5 for provide the position sensor offset for the 83 W power map. Drive controller 16 therefore stores a position sensor offset for each power map. Furthermore, the deviation of the position sensor corresponds to a time difference between the edges of the position sensor signal and the counter electromotive force zero crossing when motor 8 operates at rated speed for the power map. corresponding (see Table 5).

When operating in “Normal Operating Mode”, drive controller 16 uses position sensor offset T_POS_OFFSET to correct drive offset time T_DRIVE_OFF:

T DRIVE OFF = T_HALF_CYCLE - T ADV - T_FREE - T_POS_OFFSET

Consequently, the excitation of winding 19 is better synchronized with the

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27/35 position of the rotor 17, and therefore with the counter electromotive force, resulting in a more powerful and efficient motor system 5.

The phase difference between the position sensor signal edges and the counter electromotive force zero crossings, when expressed as a time interval, decreases by 5 with motor speed 8. Then, preferably, the drive controller 16 corrects the drive deviation time by an amount that varies with motor speed 8. However, by using a fixed time for position sensor drift, the calculations performed by drive controller 16 are considerably simplified. In particular, drive controller 16 need not calculate which time correction 10 should be applied based on motor speed 8. As a result, the number of instructions executed by drive controller 16 is reduced, and therefore a Relatively simple and inexpensive processor 30. The result is that motor system 5 is optimized for the rated speed of each power map.

When operating in modes other than “Normal Operating Mode”, the motor speed is sufficiently low, so it is unlikely that any phase difference between the position sensor signal edges and the counterforce zero crossing electromotive has significant impact on engine system 5 performance. In addition, the time spent by engine system 5 in throttle modes is relatively short. Thus, despite the simplified correction, engine system 5 performance is not adversely affected.

The operating speed range for each powermap is relatively narrow compared to the full speed range of the engine system 5. In particular, the operating speed range (minimum speed to maximum speed in Table 5) for each powermap power is not greater than 20% of full speed range 25 (zero at full speed). Consequently, the discrepancy between the position sensor deviation and the phase difference at each end of the operating range is relatively small, and therefore relatively satisfactory performance is achieved over the entire operating range using the position sensor deviation. fixed time position.

By employing a position sensor offset to correct position sensor misalignment, precise synchronization between the position sensor signal edges and counter electromotive force zero passes to a relatively small rotor can be achieved. for example with a diameter of 10 nm or less. Thus, a compact high-speed motor system can be realized 5.

After manufacturing and mounting the motor system 5, there are tolerances in the inductance and counter electromotive force of motor 8. For example, the tolerances in the geometry of stator poles 18 and the air gap influence the inductance of winding 19 as whereas the tolerances on the magnetic properties of the rotor 17, as well as the geometry of the rotor 870190022792, of 11/03/2019, p. 32/51

28/35 treferro influence the counter electromotive force in winding 19. The inductance and counter electromotive force of motor 8 may vary by up to ± 5% and ± 10%. Consequently, the output power of different motor systems 5 may vary, although the same control system 9 is used to drive motor 8.

After the motor system 5 has been assembled, the power maps employed by the drive controller 16 are finely adjusted so that the same or similar output power is achieved for each motor system 5, regardless of the inductance and voltage tolerances. counter electromotive force. Motor system 5 is finely tuned by an external fine tuning system that stores a plurality of 10-power maps. Each power map stored by the fine-tuning system comprises lead times and freewheeling turn times that drive a nominal motor (ie, which has a nominal inductance and nominal counter electromotive force) at a different output power. The fine tuning system stores each of the power maps listed in Table 2, that is, the power maps that drive the rated motor at 83 W, 96 W, 15 107 W, 136 W, and 167 W. For each of these base power maps, the fine tuning system additionally stores power maps that drive the rated motor at rated output power and at lower output power. Each basemap and respective additional powermaps drive the rated motor at distinct power levels that are separated by a predetermined amount. For the purposes of this disclosure, we will assume that for each basemap the fine-tuning system stores a single high power map that drives the engine at a higher output power and a single lower power map that drives the motor to a lower output. In addition, the high power map, the base power map and the low power map are separated by 4 W. Consequently, for the 167 W power map 25, the fine-tuning system additionally stores a 163 W power map, and a 171 W power map. For the 136 W power map, the Fine tuning additionally stores power maps of 132 W and 140 W, and so on.

Motor system 5 is fine tuned by loading base power maps into memory device 30 of drive controller 16. Motor system 5 is then powered with the 167 W power map using a power supply 17 V DC. The input power of motor system 5 is then measured. The input power for the 167 W power map should be around 190 W for a 17 V DC connection voltage, see Table 4 If the measured input power is less than 35 W, 188 W drive 16 is loaded with the high power map set. As a result, motor system 5 is driven at higher power (4 W more power) to compensate for the power difference. Conversely, if the potentiity 870190022792, of 11/03/2019, p. 33/51

If the measured input power is greater than 192 W, drive controller 16 is loaded with the low power map set. As a result, motor system 5 is powered at a lower power (4 W less power) to compensate for the power difference. Therefore, a different set of power maps is loaded on the drive controller 16 to compensate for any differences in the input power of the motor system 5. As a result, the same or similar output power can be obtained for different motors 8 with different inductances and counter electromotive forces.

By employing a plurality of power maps that are separated 10 by 4 W, the power of motor system 5 can be finely adjusted within ± 2

W. It will, of course, be appreciated that the separation of the power maps may be reduced to obtain a lower tolerance on the power of the engine system 5.

The fine-tuning process has the particular benefit that there is no need to measure the inductance or counter electromotive force of motor 8. Furthermore, by measuring the power of motor system 5 as it is driven and therefore compensated, the fine-tuning process is also able to compensate the armature reaction.

While the fine tuning system measures the input power of motor system 5, the output power can alternatively be measured. However, it is generally easier to measure the input power of motor system 5.

Instead of loading the specific map set, driving motor 8 and measuring engine power 8, motor system 5 can be finely tuned by measuring a different parameter from motor 8. The measured parameter is then compared to that of a nominal motor and, based on comparison, one of the plurality of power maps 25 stored by the fine tuning system is loaded on the drive controller 16.

For example, the counter electromotive force of motor 8 can be measured and compared with a nominal counter electromotive force value (ie the counter electromotive force for the nominal motor). If the measured counter electromotive force corresponds to the rated counter electromotive force, the base power maps are loaded on the drive controller 16.

Otherwise, a different set of power maps is loaded on drive controller 16, which takes into account the difference in counter electromotive force. Thus, it is possible to obtain more constant output power and performance for different motors, regardless of the tolerance on the counter electromotive force. As noted above, the counter electromotive force is measured while obtaining the position sensor deviation. Thus, the counter electromotive force of motor 8 can be measured without the need for any additional process.

By controlling the feed angle and the freewheel angle in response to the

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With changes in both excitation voltage and speed, control system 9 is capable of driving motor 8 at constant output power over a range of excitation voltages and motor speeds. In the present context, constant output power shall be understood as a variation in motor output power 8 of not more than ± 5%.

Control system 9 drives motor 8 not only at constant output power, but also at relatively high efficiency (ie the ratio of output power to input power). By controlling the feed angle and freewheel angle in response to changes in both excitation voltage and speed, it is possible to achieve at least 75% efficiency over the range of excitation voltages and motor speeds. In fact, for the power maps listed in Table 2, an efficiency of at least 80% can be achieved. For example, as shown in the figures for input and output power listed in Table 4, an efficiency of around 88% can be achieved with the free-wheeling angles of 15 167 W.

The range of excitation voltages over which constant output power and / or high efficiency is obtained is relatively wide. For the 6 cell battery module, the excitation voltage range is 16.8 to 23.0 V, while for the 4 cell battery module, the excitation voltage range is 11.2 to 14V. 8 For both voltage ranges, 20 the minimum voltage is less than 80% of the maximum voltage. This represents a relatively large range over which constant output power and / or high efficiency are obtained. Thus, the control system 9 is especially suitable for use in driving a motor of a battery-powered product, where the excitation voltage varies as the battery discharges.

Although each operating speed range is relatively narrow compared to the full speed range, each operating speed range nevertheless encompasses at least 10 krpm (Table 5). In addition, the minimum speed for each operating speed range is greater than 60 krpm, while the maximum speed for each operating speed range is greater than 80 krpm. In fact, at 30 the 167 W power map, the maximum speed of the operating speed range is greater than 100 krpm. Above this kind of speed range, large differences in output power would arise without the control offered by the control system. Moreover, efficiency at these relatively high speeds would generally be unsatisfactory without the control provided by the control system.

With control system 9, a single phase permanent magnet motor 8 can be driven at relatively high speeds, and in particular at speeds above 60 krpm. Moreover, high speeds are achieved at relatively high efficiency. In

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In fact, as can be seen from Table 4, it is possible to achieve speeds in excess of 100 krpm for an input power of less than 200 W. Therefore, it is possible to achieve high speeds with a relatively high efficiency without the need for windings. additional phase, which would increase the cost and size of the engine.

Control system 9 employs three different modes of operation that collectively achieve uniform and efficient motor performance 8.

When operating in the "Low Speed ​​Acceleration Mode", winding 19 is excited in sync with the zero-passes of the counter electromotive force in winding 19. At these relatively low speeds, the counter electromotive force in winding 19 is relatively small. and does not impact the ability to conduct current, and therefore energy, to the winding 19. However, by energizing winding 19 in sync with the counter electromotive force, the control required to drive motor 8 can be kept relatively simple.

While operating in “High Speed ​​Acceleration Mode”, the magnitude of the counter electromotive force begins to influence the ability to conduct current to winding 19. By exciting current 19 before the counter electromotive force, current is driven to the winding at an earlier stage. Consequently, more energy is driven to the motor 8. By excitation of winding 19 prior to counter electromotive force for a fixed period of time, winding 19 is excited prior to counter electromotive force by an angle that increases with rotor speed. Consequently, as motor 8 accelerates, current is driven to winding 19 at an increasingly earlier stage, and thus more energy is driven to winding 19. Moreover, by employing a fixed lead time, the control required to drive motor 8 is relatively simple.

While operating in “Normal Operating Mode”, the magnitude of the counter electromotive force considerably affects the ability to conduct current to winding 19. As in “High Speed ​​Acceleration Mode”, winding 19 is excited before the counter electromotive force of that the current is driven to winding 19 at an earlier stage. However, changes in motor speed 8 influence the magnitude of the counter electromotive force, and thus the output power of motor 8. Thus, by varying the lead time in response to changes in speed, the output power of motor 8 can be better controlled. In particular, the lead time may be increased with increasing engine speed. The increase in counter electromotive force is then offset by the current being conducted to winding 19 at an earlier stage. As a result, the same or similar output power can be obtained regardless of changes in speed.

The control system 9 therefore employs different modes of operation which operate in the same way. 36/51

32/35 am to speed up motor 8 evenly and efficiently to operating speed, and then drive motor 8 to a constant output power.

In the embodiment described above, each power map stores a lead time for each of a plurality of voltages. However, instead of storing the lead times, each power map can instead store the sum of the lead time and the freewheeling spin time. This then simplifies the calculation of the drive deviation time, T_DRIVE_OFF, which is directly proportional to the sum of the lead time and freewheeling time obtained from the power map. Alternatively, since the semicycle time T_HALF_CYCLE at each nominal speed is known (e.g. 303.03 ps at 99 krpm, 320.86 ps at 93.5 krpm, and so on) each The power map may instead store a drive deviation time rather than a lead time for each of the plurality of voltage levels. This then simplifies the calculations performed by the drive controller 16. Moreover, as noted above, instead of storing lead times and freewheeling times, the power map could alternatively store lead angles and freewheeling angles. Thus, in a more general sense, each power map stores a first control value and a second control value for each of a plurality of voltage levels. The first control value is then proportional to a feed angle and is used to control the angle or moment at which winding 19 is excited. The second control value is then proportional to a freewheeling angle and controls the angle or time during which winding 19 is freewheeled. Drive controller 16 then excites winding 19 prior to counter-electromotive force zeroing at a time defined by the first control value, and freewheels winding 19 for a time defined by the second control value. . Speed ​​correction maps then store appropriate speed correction values ​​to correct the first control value and the second control value. In particular, the ground speed correction map stores speed correction values ​​that are applied to the first control value, and the freewheeling speed correction map stores speed correction values ​​that are 30 applied to the second control value. control value.

In the embodiment described above, each power map stores control values ​​that have their speed corrected using the correction values ​​stored in a speed correction map. Storing correction values ​​has the benefit of reducing overall memory requirements. In particular, each correction value is less than a corresponding control value. However, instead of storing one power map and two speed correction maps for each output power level, drive controller 16 could alternatively store two master maps,

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33/35 each storing a control value for each of a plurality of excitation voltage speeds.

In the embodiment described above, both the lead time and the freewheeling time have their speed corrected. However, the constant output power over each operating speed range could also be achieved by setting one of the lead time and freewheeling time and varying the other. Since winding 19 is freewheeled during a period of counter-electromotive force drop, the output power of motor system 5 is more sensitive to changes in lead time. Thus, of the two, the freewheeling time is preferably kept fixed and the advance time has its speed corrected. By setting the freewheel running time, the calculations performed by the drive controller 16 are further simplified. In addition, the freewheeling speed correction map can be omitted for each powermap, thereby reducing the memory requirements of the drive controller 16. Although the freewheeling time can be set to 15 different speeds. , the corresponding free-wheel turning angle is not. This is because the electrical angle for a fixed time period varies with motor speed 8.

Each power map stores control values ​​that are calculated based on a nominal speed for motor 8. The speed correction values ​​are then applied to the control values ​​if the motor speed deviates from the nominal speed 20. In addition, the position sensor offset for each power map corresponds to a time difference between the position sensor signal edges and the counter electromotive force zero crossings when motor 8 operates at rated speed. Thus, the control system 9 is optimized for operation at rated speed within each operating speed range. The rated speed can therefore be chosen to optimize product performance 1. For example, the nominal speed may correspond to a speed at which motor 8 operates predominantly. Alternatively, or in addition, the rated speed may correspond to a speed at which peak performance is achieved for product 1. For example, as shown in Figure 8, product 1 may be a vacuum cleaner for which airwatt peaks at a specific speed of 30 within each operating speed range. The nominal speed for each power map, then, corresponds to the speed at which the peak airwatt is reached.

The specific lead times, freewheeling times and speed correction values ​​listed in Tables 4 to 7 are given by way of example only. 35 The specific control values ​​and speed control values ​​required to achieve constant output power will depend on the specific motor characteristics. 8. The free-wheel turning and turning angles for a specific motor are obtained from the simulatedPetition 870190022792 of 11 / 03/2019, p. 38/51

34/35 that generates the best performance (eg, best efficiency) for the engine at the desired output power within the constraints of the control system. Within the simulation, restrictions may be placed on the behavior of the feed angle and the freewheeling angle. For example, the lead angle may be restricted and the freewheeling angle may be reduced with the reduction of excitation voltage and / or increase of motor speed.

Although reference has been made to the variation of both the forward angle and the freewheeling angle in response to changes in excitation voltage and motor speed, considerable advantages can be obtained, however, by varying only 10 µm of angle. feedrate or free-wheel turning angle. In particular, as already noted, by freewheeling the winding 19 within the region of the falling counter-electromotive force, a more efficient motor system 5 can be obtained. In addition, by varying the freewheeling angle of rotation in response to changes in voltage and / or speed, better control of both the efficiency and output power of the motor system can be achieved regardless of any control of the engine. feed angle.

As shown in Figure 8, product 1 may take the form of a vacuum cleaner, in particular a portable vacuum cleaner, having an accessory 4 in the form of a motorized brush bar. The output power of motor system 5, and therefore the vacuum suction power, will then vary depending on whether or not the brush bar is connected to the vacuum cleaner and / or on. In addition, power mode selector switch 7 can be used by the user to select a high power mode when greater suction is required. Since motor system 5 maintains constant output power over each operating speed range, the vacuum cleaner 25 is capable of maintaining constant suction over a range of loads. Furthermore, since motor system 5 maintains constant output power in response to changes in excitation voltage, the vacuum cleaner is able to maintain constant suction in response to changes in power supply voltage 2. In particular, when power supply 2 is a battery module, the vacuum cleaner is capable of maintaining constant suction as the battery module discharges.

Although the power supply 2 of the embodiment described above is a DC power supply, and in particular a DC battery module, the power supply 2 could also comprise an AC power supply, a rectifier and a filter for supplying a DC voltage. Furthermore, although each of motor 8 and inverter 11 of the embodiment described above comprises a single phase, motor 8 and inverter 11 may comprise additional phases. Drive controller 16 then drives each phase in the manner described above.

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35/35

In particular, each phase is excited in sync with the counter electromotive force zero passes during “Low Speed ​​Acceleration Mode”, and each phase is sequentially excited and rotated in freewheel during “High Speed ​​Acceleration Mode”. ”And“ Normal Operation Mode ”. Position sensor 13 described above is a Hall effect sensor. However, alternative position sensors capable of generating a signal indicating the position of the rotor 17, and thus the zero passes of the counter electromotive force in winding 19, could also be employed, such as an optical sensor.

To date, reference has been made to a control system 9 which controls the operation of a motor 8. However, the control system 9 could also be used to control the operation of a generator or other electric machine.