System and process for energizing loads through a control unit

(54) Title: SYSTEM AND PROCESS FOR ENERGIZING LOADS BY A CONTROL UNIT (71) Depositor (s): Brazilian Compressor Company S / A Embraco (BR / SC) (72) Inventor (s): Ronaldo Ribeiro Duarte, Marcos Guilherme Schwarz (74) Attorney: Antonio Maurício Pedras Arnaud (57) Abstract: SYSTEM AND PROCESS FOR ENERGY OF LOADS BY A CONTROL UNIT. Said system comprising: connection elements (10) each including a processing unit (12) operatively connected to a respective power switch (11), to lead the latter to opening and closing conditions, de-energizing and energizing a respective load adjacent and electrically coupled to the connecting element (10); a pair of electrical conductors (21) connected to a power supply network (2) and arranged so as to define a means of energization common to the connection elements (10) and the control unit (3); and a signal conductor (22), not galvanically isolated from the mains, common to the processing units (12) and the control unit (3), connecting them in order to allow the control unit (3) to instruct, through the processing units (12) and by coded electrical signals, the opening and closing of each respective power switch (11).

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SYSTEM AND PROCESS FOR ENERGIZING LOADS BY A CONTROL UNIT

Field of invention

The present invention refers to a system and a process to enable power and serial bidirectional communication to control internal loads to household appliances, such as refrigerators, freezers, washing machines, etc., from a control unit.

History of the Invention

Household appliances in general have a large number of electrical charges distributed by the system, such as lamps, fans, valves, motors, etc., which are essential for the operation of the equipment, and such loads are typically commanded by a control unit, which applies or not. tension on them depending on the needs of the process. The power control over the loads is done by semiconductor alternating current switches of the triac or electromechanical type, such as electromagnetic relays, these switches being typically located in a power unit that receives the voltage from the power supply which is then distributed to loads through appropriate electrical cables. Figure 1 shows a typical wiring diagram for a refrigerator 1, operatively connected to an electrical network 2 and comprising a control unit 3, a power unit 4, a fan 5, a defrost resistor 6, an internal lamp 7 and a compressor 8. As can be seen, the existence of several loads in the system implies a high number of cables 9 distributed by the device, increasing the electromagnetic noise, the cost of wiring and the difficulty of assembly, and the number of loads and wiring grows along with the complexity of the system.

To reduce the problems described involving cargo distributed in the automotive industry, serial communication standards were developed in order to eliminate

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individual power cables for each of the loads in the system, the best known being the CAN standard. For applications where the system does not require high speed or large data flow, a standard known as LIN has been developed. In these applications, the power is supplied directly to the load, which has a local power switch, and the control unit 2 commands the selective energization of the load, through serial communication. In both serial communication standards, the signal level used in the communication is different from the voltage level of the alternating current supply network, so for appliances applications, special circuits should be used for signal conversion, as well as the installation of two conductors exclusive extras for serial communication.

A serial communication standard known as X-10 specifies serial communication directly through the supply network, from the modulation of a high frequency signal over the network, normally used for communication between devices in a home or even for access to the internet, eliminating the need for telephone or network cables. The major disadvantage of this standard is the need for a normally complex and relatively high filtering circuit to separate the communication signal from the power supply. There is also the standard of industrial communication called AS-i, whose principle is similar to the X-10 already described, where power and communication travel through the same conductors, in different frequency spectra, and in this last case, the power is in continuous voltage, normally 24Vdc. 0 AS-i standard is widely used in industrial networks for communication with sensors and actuators.

It can be concluded from the basic description of some of the existing communication standards, that all require dedicated and complex electronic circuits for the tasks of separation and / or treatment of the signals, • · • · making them unfeasible in systems whose cost it is a major factor and there is no need for high speed or large flow of transmitted data.

Objectives of the invention

Thus, it is an objective of the present invention to provide a system for energizing loads by a control unit, for internal loads to household appliances, from a serial communication network, with simple and robust topology, of low cost and that allows: reduction in the cost of manufacturing and assembling appliances, simplifying the assembly and reducing the steps involved in the manufacture of appliances and the large-scale use of these appliances.

It is another objective of this invention to provide a system as mentioned above and that allows the modularity and expansion of said system.

It is yet another objective of this invention to provide a system as mentioned above and that does not require the use of specific boxes and power units for each project.

It is another objective of this invention to provide a process for energizing loads by a control unit, said loads being internal to household appliances, which simplifies the assembly of current systems.

It is another objective of this invention to provide a process as mentioned above and that allows implementation with low cost microcontrollers.

Summary of the invention

These and other objectives of the present invention are obtained through a system for energizing loads by a control unit, said loads being energized from an electrical network, said system comprising: connection elements comprising, each, a power switch and a processing unit operatively connected to the power switch, in order to drive the latter to opening and closing conditions, de-energizing and energizing a respective load

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• · • · adjacent and electrically coupled to the connection element; a pair of electrical conductors connected to the mains and arranged so as to define a means of energization common to the connection elements and the control unit; and a signal conductor, not galvanically isolated from the electrical network, common to the processing units and the control unit, connecting them in such a way as to allow the control unit to instruct, through the processing units and by coded electrical signals, the opening and closing each respective power switch.

The charge energizing system in question operates, according to the present invention, according to a process including the steps of: a- connecting the electrical network to the control unit through a pair of electrical conductors; b- connect each load electrically and through a respective power switch to the referred pair of electric conductors; c- operatively associate to each power switch, a respective processing unit designed in order to lead the respective power switch to opening and closing conditions; d- connect the control unit to the processing units by means of a single signal conductor, not galvanically isolated from the electrical network, common to said units in order to instruct, through the processing units, the conditions for opening and closing the respective power switches.

Brief description of the drawings

The invention will be described with reference to the attached drawings, given by way of example only and in which: Figure 1 represents, schematically, a refrigerator in which the wiring between the control unit, the electrical network and the various loads in it is built according to with the prior art;

Figure 2 represents, schematically, a refrigerator in which the wiring between the control unit, the electrical network and the various loads in it is constructed

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• ·

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according to the present solution;

Figure 3 represents, schematically, a configuration of a system for energizing loads by a control unit, with electronic control, built in accordance with the present solution;

Figure 4 represents, schematically, another configuration of the system for energizing loads of the present solution;

Figure 5 represents, schematically, a first electronic configuration for the connection element of the charge energizing system of the present invention;

Figure 6 schematically represents a second electronic configuration for the connection element of the charge energizing system of the present invention; and

Figure 7 represents, schematically, an electronic configuration for the connection element associated with the control unit of the load energizing system of the present invention.

Description of illustrated configurations

As mentioned at the beginning of this report and the drawings presented, the system for energizing loads by a control unit of the present invention will be described for a refrigeration device such as a refrigerator 1, in which the loads to be energized can be represented by its components, as illustrated in figures 1 and 2 and which, as already described above, comprises, operatively connected to an electrical network 2, a control unit 3, a fan 5, a defrost resistor 6, an internal lamp 7 and a compressor 8.

However, it must be understood that the inventive concept presented here provides that said energization system can be applied to any device having its loads energized by command of a central control unit.

The system for energizing loads by a unit of

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The control of the present invention comprises, as described below, connection elements 10 each comprising an electronic circuit having a power switch 11 and a processing unit 12 operatively connected to the power switch 11, in order to drive the latter to conditions opening and closing, de-energizing and energizing a respective load, adjacent and electrically coupled to the connecting element 10. For a refrigerator 1, each load can be represented by one of the constituents of: fan 5, defrost resistor 6, internal lamp 7 and compressor 8.

According to the present invention, each connection element 10 can be connected to a cable 20 with at least 3 wires, two of which define a pair of electrical conductors 21, connected to the mains 2 and arranged so as to define a means power supply common to the connection elements 10 and the control unit 3, and a third wire defines a signal conductor 22, not galvanically isolated from the electrical network 2, related to bidirectional serial communication, common to processing units 12 and control unit 3, connecting them in such a way as to allow control unit 3 to instruct, through processing units 12 and by coded electrical signals, the opening and closing of each respective switch power 11.

The pair of electrical conductors 21 and signal conductor 22 of the cable of the present invention must travel each of a plurality of loads of the device provided with the energization system in question, each of said loads being connected to said conductors through a respective connection element 10, as shown in figure 2. In this way, the individual cables that usually connect the control unit 3 to the loads will be eliminated, as occurs in the construction of the previous technique illustrated in figure 1, as well as the assembly steps for these will be simplified.

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• · 9 9 cables in the assembly lines of the devices provided with the energization system of the present invention, since in addition to the existence of a smaller number of wires distributed by said device, the connection elements 10 of the present invention can be provided with a system connection cable optimized for quick connection on the cable. The command to turn each individual load on and off is done by the control unit 3, which can be anywhere in the system.

The serial communication of the present invention is of the non-simultaneous bidirectional type, that is, of the halfduplex type, master and slave, so that the control unit 3 is the master and each of the connection elements 10 is a slave and responds only to the commands sent by the master.

According to the present invention, the signal conductor 22 is arranged along the pair of electrical conductors 21, with the cable 20, defining a set of these conductors, running through all the connection elements 10 and the control unit 3.

In a construction of the present invention for the connecting element 10, it comprises a body carrying input terminals 13, each loosely coupling a conductor selected from the pair of electrical conductors 21 and the signal conductor 22, one of the input terminals 13, associated with an electrical conductor 21, being operatively connected to the power switch 11; and output terminals 14, one of which is operatively connected to said power switch 11 and the other directly to the other input terminal 13, said output terminals 14 being releasably coupled to a respective load.

The input terminals 13 can be, for example, of the type suitable for quick coupling, such as the piercing type.

Each connection element 10 also includes, provided inside the respective body, in addition to the power switch

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··· «· • · and the processing unit 12, a serial interface 15, operatively connected to an input terminal 13, energizing, an input terminal 13, communication and processing unit 12, in order to allow at least one of the energizing operations, at reduced voltage, of the connection element 10 and two-way serial communication between it and the control unit 3.

Each connection element 10 also comprises a detector means 16, of zero voltage point of the electrical network, operatively associated with the respective processing unit 12, in order to provide synchronism to the communication between the control unit 3 and each processing unit 12 through of the signal conductor 22.

In a particular form of construction, illustrated in figures 3 and 5, connection elements 10 of the slave type, that is, other than that coupled to the control unit 3, also comprise a power supply 17, preferably of the capacitive type, since the consumption of the circuit is very low, said power supply 17 having an input electrically connected to one of the input terminals 13, energizer and an output electrically connected to the internal electronic circuit of the connection element 10. In this configuration the energization of each connection element 10 occurs through the pair of energization connectors 21, while the signal conductor 22 operates only the bidirectional transmission of communication signals between the control unit 3 and each connecting element 10. For this construction of connection element 10, of the slave type, it is not necessary that a connection element 10, of the master type, associated with the control unit 3 has the output of its power supply 17 connected to the serial interface 15.

In the solution illustrated in figures 4 and 6, the connection elements 10 of the slave type do not have the power supply 17. In this configuration the energization of each connection element 10 occurs through the signal conductor 22, which has the function of bidirectional serial communication between the control unit 3 and the processing unit 12 of each connection element 10 and the energizing function the respective connection element

10, these functions being selective and alternated in time, as instructed by the control unit 3 and carried out when the supply network frequency passes through zero. In this construction, each connection element 10 of the slave type comprises a serial interface 15 that allows the operation of bidirectional serial communication and that also allows the extraction of the supply voltage, at reduced voltage, from the signal conductor 22, of communication, to the internal circuit of the respective connection element 10.

For this slave connection element construction 10, the connection element 10 coupled to the control unit 3 comprises a power supply 17, having an input electrically connected to one of the energizing input terminals 13 and an output electrically connected to the serial interface 15, so that the latter allows the operation of bidirectional serial communication with the connection elements 10 operatively coupled to the loads and the supply of the supply voltage, at reduced voltage, through the signal conductor 22, of communication, for connection elements 10. With this solution it is possible to reduce the size and cost of the circuit, further enabling its use on a large scale.

Figure 5 illustrates a constructive form of circuit for a connection element 10 of the type that has a power supply 17. According to this construction, in a condition where the circuit is not transmitting data, a first transistor Q1 of the serial interface 15 is in an open state and the communication terminal 13, indicated by A in said figure 5, is brought to a voltage level -Vcc, through a fifth resistor R5 of the serial interface 15. Data transmission occurs when the processing unit 12 of the connecting element 10 instructs one of the closing and opening conditions of the first transistor Q1, from an output of the processing unit 12, indicated by P3, leading to the voltage level. from point A to 0V or -Vcc, depending on the bit transmitted. The data is read by a digital input P4 of the processing unit 12, as shown in figure 5, after passing through a filter formed by a first capacitor Cl and a fourth resistor R4, preventing the passage of noise to the processing unit 12. 0 circuit provides for asynchronous serial communication at low speed, although it also allows the implementation of synchronous communication, using the voltage of the supply network for synchronism, obtained from a first resistor RI, the detector medium 16 and a first and a second diode protection D1 and D2 of said sensor means 16, applying a signal to the PI input of the processing unit 12.

The advantage of synchronization from the electrical network 2 is the simplification of software for serial communication, since there is no need for strict timing control, allowing the use of processing units in the form of low-cost micro-controllers.

The European patent document EP 0711018A2 presents a solution in which the synchronization is through the supply network, but with the conventional use of two or more wires for communication between loads, and this solution requires that such wires be galvanically isolated, so as not to allow current to flow through them, due to installation safety requirements for the application to which this solution refers. Figure 6 presents an electronic diagram of a constructive variant in which the power supply 17 is not shown. In this construction the circuit is fed by the voltage available from the signal conductor 22, which has the function of supplying current to the internal circuit of the connection element 10, in addition to serving as a means for bidirectional serial communication. Unlike the previous techniques, of data multiplexing and supply simultaneously, the solution of the present invention allows to divide the time, in the signal conductor 22, between communication and energizing the circuits. Data transmission occurs, as already described, from the selective closing and opening of the first transistor Ql, forcing the voltage of the communication line to OV or -Vcc, depending on the bit transmitted and, in that interval, a second transistor Q2 of the connection element 10 illustrated in figure 6, remains open from the application of a voltage -Vcc on an output pin P5 of the processing unit 12. In the

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closing of the second transistor Q2, applying an OV voltage to the output pin P5 of said processing unit 12, so that a bus capacitor

C2 can be charged, supplying current to the circuit in the subsequent moments when the signal conductor 22 has the communication function again and until the processing unit 12 again instructs the closing of the transistor Q2 interrupting the communication to energize the respective connection element 10 .

Figure 7 illustrates a constructive form of a circuit suggested for a connection element 10 of the master type and which is operatively associated with the control unit 3, said connection element 10 including, in addition to the constituents already discussed for connection elements 10 of the types associated with loads, a third transistor Q3, which remains in an open state as long as an output P4 of processing unit 12 has a voltage in -Vcc, allowing normal data transmission and reception. In the time interval for energizing the circuits, the processing unit 12 controls the third transistor Q3 to close, applying a voltage of

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0V at the pin of output P4, allowing the charge stored in the second capacitor C2 and generated by the power supply 17 to be supplied to the signal conductor 22. Simultaneously the other connection elements 10 of the system under description and associated with loads, enable the power input for your individual storage capacitors.

The synchronism foreseen for the communication and energization intervals is made from the mains 2, so that, for example, in positive half cycles, the signal conductor 22 operates in communication. In this situation, all the connection elements 10 will have their second transistors Q2 in the open state (fig. 06), as well as the connection element 10, acting as master, will command a third transistor Q3 to also remain in the open state. Communication will take place normally, according to already known concepts of master-slave protocols. In the negative half cycles no communication will be made, therefore all the first communication transistors Q1 will be in the open state and the processing unit 12 of each connection element 10 will control the second transistors Q2 (fig. 06) to enter the closed state, allowing current to flow through them and, simultaneously, the connecting element 10 acting as master will command the third transistor Q3 (fig. 07) to close, allowing the stored and generated energy to flow to the elements connection 10 acting as slaves, feeding them. Both the connecting elements 10 acting as slaves as well as the one acting as master are driven to synchronism from the zero crossing of the mains voltage 2.

Considering the half cycle of the electrical network 2 dedicated to the supply of energy to the circuits of the connection elements 10, the remaining time is 50 semi cycles available for communication, in a 50Hz network, that is, a transfer rate of 50 bits per second , or approximately 5 bytes per second, considering ····· · · · ···· • · ······· · ··· · • · · ···· ·· · ·· • · · · · ··· · · · · ♦ signaling bits. As the basic commands are on and off, it is possible, in a single byte, to send the address of the controlled connection element 10 and the complete command and, if a byte is considered as a response, two commands per second will be possible. 0 protocol used must provide for the constant sending of a check character by the connection element 10 acting as master and, in the event of failure, each of the connection elements 10 slaves, or of the controlled type, must disconnect the respective load as a safety measure, as there may have been an unexpected interruption in the communication line.

The implementations described cover connection elements 10 of the controlled type that drive loads. However, it should be understood that the scope of the present invention can be extended to connection elements 10 that operatively connect control unit 3 to at least one sensor medium providing signals representative of operational conditions of an apparatus provided with said energization system. , so that said connection elements receive input signals, such as switches, keys, digital and analog sensors, thermostats, etc.

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