A protection circuit and a control method of the protection circuit

Abstract

The application provides a protection circuit and a control method of the protection circuit, and the circuit comprises a three-phase inverter circuit, a first diode, a second diode, a third diode and a charging circuit. The cathode of the first diode is connected with the first end of the transistor on the upper tube bridge wall of the switch tube bridge wall, and the anode of the first diode is connected with the positive pole of the first capacitor. The anode of the second diode is connected with the second end of the transistor on the lower tube bridge wall of the switch tube bridge wall, and the cathode of the second diode is connected with the negative pole of the first capacitor. The third diode is connected with the second diode and the transistor on the lower tube bridge wall of the switch tube bridge wall in parallel and then grounded. The three phases of the motor are respectively connected with the three common ends of the upper and lower tube bridge walls of the three switch tube bridge walls in one-to-one correspondence, and each phase of the motor is connected with a charging circuit. Through the application, the technical problem that the freewheeling energy is easy to damage the bus capacitor in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and in particular to a protection circuit and a control method for the protection circuit. Background Technology

[0002] During periods of motor deceleration, overcurrent fault triggering, and control signal dead time, the motor winding current cannot change abruptly, resulting in a freewheeling loop in the inverter circuit. This means the motor, acting as an energy source, reverse-charges the bus capacitor, potentially increasing ripple and even damaging it. Furthermore, the energy in this freewheeling loop is not effectively utilized. A typical three-phase inverter circuit is as follows: Figure 1 As shown, C0 is the bus capacitor, X1 to X6 are transistors in a typical three-phase inverter circuit, and U, V, and W are the three phases of the motor in a typical three-phase inverter circuit. Existing three-phase inverter circuits suffer from the technical problem that freewheeling energy can easily damage the bus capacitor. Summary of the Invention

[0003] The purpose of this application is to provide a protection circuit and a control method for the protection circuit, solving the technical problem in the prior art where freewheeling energy easily damages the bus capacitor. The specific technical solution is as follows:

[0004] In a first aspect of this application, a protection circuit is provided, comprising: a three-phase inverter circuit, a first diode, a second diode, a third diode, and a charging circuit; wherein, the three-phase inverter circuit includes a first capacitor, a motor, and three switching bridge walls; each switching bridge wall has two transistors; the first and second terminals of the transistors are connected to the three-phase inverter circuit, and the third terminal of the transistor is connected to the transistor's driving circuit; the cathode of the first diode is connected to the first terminal of the transistor on the upper bridge wall of the switching bridge wall, and the anode of the first diode is connected to the positive terminal of the first capacitor; the anode of the second diode is connected to the second terminal of the transistor on the lower bridge wall of the switching bridge wall, and the cathode of the second diode is connected to the negative terminal of the first capacitor; the third diode is connected in parallel with the second diode (connected in series) and the transistor on the lower bridge wall of the switching bridge wall and then grounded; the three phases of the motor are respectively connected to the three common terminals of the upper and lower bridge walls of the three switching bridge walls, and each phase of the motor is connected to a charging circuit.

[0005] In the second aspect of the application, a control method of the protection circuit is also provided. The method comprises: obtaining the conduction state of the transistors in the three-phase inverter circuit when the motor is in a stable operation state; turning off all the transistors in the three-phase inverter circuit when the motor is in a speed reduction operation state, and determining the transistors in the conduction state before being turned off; determining the charging circuit connected to the transistors in the conduction state before being turned off; and charging the second capacitor in the charging circuit when the transistor in the charging circuit is in the conduction state.

[0006] In the third aspect of the application, an electronic device is also provided. The electronic device comprises a processor, a communication interface, a memory and a communication bus. The processor, the communication interface and the memory can communicate with each other through the communication bus. The memory is used to store a computer program. The processor is used to execute the program stored in the memory, and implement the control method of the protection circuit in the second aspect.

[0007] In the fourth aspect of the application, a computer readable storage medium is also provided. The computer readable storage medium stores instructions. When the instructions are executed on a computer, the computer executes the control method of the protection circuit in the second aspect.

[0008] The protection circuit and the control method of the protection circuit provided by the embodiment of the application, the protection circuit comprises a three-phase inverter circuit, a first diode, a second diode, a third diode and a charging circuit; wherein the three-phase inverter circuit comprises a first capacitor, a motor and three switch tube bridges; two transistors are arranged on each switch tube bridge; the first end and the second end of the transistor are connected to the three-phase inverter circuit, and the third end of the transistor is connected to the driving circuit of the transistor; the cathode of the first diode is connected to the first end of the transistor on the upper tube bridge of the switch tube bridge, and the anode of the first diode is connected to the positive pole of the first capacitor; the anode of the second diode is connected to the second end of the transistor on the lower tube bridge of the switch tube bridge, and the cathode of the second diode is connected to the negative pole of the first capacitor; the third diode is connected to the second diode and the transistor on the lower tube bridge of the switch tube bridge in parallel and then grounded; the three phases of the motor are connected to the three common ends of the upper and lower tube bridges of the three switch tube bridges in one-to-one correspondence respectively, and each phase of the motor is connected to a charging circuit; the conduction state of the transistor in the three-phase inverter circuit is obtained under the condition that the motor is in a stable running state; all the transistors in the three-phase inverter circuit are turned off under the condition that the motor is in a speed reduction running state, and the transistor in the conduction state before being turned off is determined; the charging circuit connected to the transistor in the conduction state before being turned off is determined; the second capacitor in the charging circuit is charged under the condition that the transistor in the charging circuit is in the conduction state; that is, the freewheeling energy generated by the motor is led to the charging circuit based on the unidirectional conduction of the diode, the reverse charging of the motor to the bus capacitor is avoided, and the energy of the freewheeling circuit is collected by the charging circuit, so that the technical problem that the freewheeling energy is easy to damage the bus capacitor in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced.

[0010] Figure 1 It is a typical three-phase inverter circuit structure schematic diagram;

[0011] Figure 2 It is one of the protection circuit structure schematic diagrams in the embodiment of the application;

[0012] Figure 3 It is the second protection circuit structure schematic diagram in the embodiment of the application;

[0013] Figure 4 It is one of the control method flowcharts of the protection circuit in the embodiment of the application;

[0014] Figure 5 It is the second control method flowchart of the protection circuit in the embodiment of the application;

[0015] Figure 6 Figure 3 is a flow chart of a control method of a protection circuit according to an embodiment of the present application;

[0016] Figure 7 Figure 4 is a flow chart of a fourth exemplary control method of a protection circuit according to an embodiment of the present application;

[0017] Figure 8 Figure 5 is a schematic diagram of a second capacitor power supply according to an embodiment of the present application

[0018] Figure 9 Figure 6 is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions of the embodiments of the present application. Obviously, the described embodiments are a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0020] In the following description, suffixes such as "module" and "unit" used to represent elements are only for the convenience of description of the present application, and have no specific meaning in itself. Therefore, "module" and "unit" can be used interchangeably.

[0021] The technical solutions of the embodiments of the present application will be described below in combination with the accompanying drawings. The embodiments of the present application provide a protection circuit, as shown in the drawings, the protection circuit comprises a three-phase inverter circuit, a first diode D1, a second diode, a third diode and a charging circuit; wherein the three-phase inverter circuit comprises a first capacitor C1, a motor and three switch tube bridge walls; two transistors are arranged on each switch tube bridge wall; the first end and the second end of the transistor are connected to the three-phase inverter circuit, and the third end of the transistor is connected to the driving circuit of the transistor; Figure 2

[0022] The cathode of the first diode is connected to the first end of the transistor on the upper tube bridge wall of the switch tube bridge wall, and the anode of the first diode is connected to the positive pole of the first capacitor; the anode of the second diode is connected to the second end of the transistor on the lower tube bridge wall of the switch tube bridge wall, and the cathode of the second diode is connected to the negative pole of the first capacitor; the third diode is connected in parallel with the second diode and the transistor on the lower tube bridge wall of the switch tube bridge wall, and then grounded;

[0023] The three phases of the motor are respectively connected to the three common ends of the upper and lower tube bridge walls of the three switch tube bridge walls one by one, and each phase of the motor is connected to a charging circuit.

[0024] ​It should be noted that the protection circuit provided in the application can be applied to a washing machine, and can also be applied to other scenarios in which a motor generates freewheeling energy; the upper bridge arm transistors of the switch tube bridge arm include Q1, Q3 and Q5, the lower bridge arm transistors of the switch tube bridge arm include Q2, Q4 and Q6, the second diodes include D2, D3 and D4, the third diodes include D5, D6 and D7, GND is the ground, U, V and W are three phases of the motor respectively, and A is a needle seat; the on-off of the transistors is controlled by a driving circuit; the charging circuit and the driving circuit are connected to the needle seat and connected to the motor and the protection circuit through the needle seat; due to the presence of the first diode D1, the freewheeling of the upper bridge arm transistors Q1, Q3 and Q5 cannot flow to the capacitor C1 through the body diode, but is guided to the charging circuit, thereby avoiding freewheeling loss to the transistors; due to the presence of the second diodes D2, D3 and D4, the freewheeling of the lower bridge arm transistors Q2, Q4 and Q6 cannot pass through the body diode, but is guided to the third diodes D5, D6 and D7 to complete the freewheeling path, thereby avoiding freewheeling loss to the transistors.

[0025] Through the above protection circuit of the embodiment of the application, the three-phase inverter circuit, the first diode, the second diode, the third diode and the charging circuit are included; wherein the three-phase inverter circuit includes a first capacitor, a motor and three switch tube bridge walls; two transistors are arranged on each switch tube bridge wall; the first end and the second end of the transistor are connected to the three-phase inverter circuit, and the third end of the transistor is connected to the driving circuit of the transistor; the cathode of the first diode is connected to the first end of the transistor on the upper bridge wall of the switch tube bridge wall, and the anode of the first diode is connected to the positive electrode of the first capacitor; the anode of the second diode is connected to the second end of the transistor on the lower bridge wall of the switch tube bridge wall, and the cathode of the second diode is connected to the negative electrode of the first capacitor; the third diode is connected in parallel with the second diode and the transistor on the lower bridge wall of the switch tube bridge wall and then grounded; the three phases of the motor are connected to the three common ends of the upper and lower bridge walls of the three switch tube bridge walls one by one in a one-to-one correspondence, and each phase of the motor is connected to a charging circuit; that is, the first diode, the second diode and the third diode are arranged, and based on the unidirectional conductivity of the diode, the freewheeling energy generated by the motor is guided to the charging circuit, and the protection circuit provided in the application can avoid reverse charging of the motor to the bus capacitor and collect the energy of the freewheeling circuit from the charging circuit, thereby solving the technical problem that the freewheeling energy in the prior art is easy to damage the bus capacitor.

[0026] In the optional implementation of the embodiment of the application, the protection circuit provided in the application is as follows Figure 3As shown, the charging circuit includes a second capacitor, a first resistor, a fourth diode, a fifth diode, and a transistor, wherein the first end of the transistor in the charging circuit is connected to the motor, the second end of the transistor in the charging circuit is connected to the anode of the fourth diode, the third end of the transistor in the charging circuit is connected to the driving circuit of the transistor in the charging circuit; the cathode of the fourth diode is connected to one end of the first resistor, the second capacitor and the fifth diode are connected in parallel, and the other end of the first resistor is connected to the other end of the second capacitor and the fifth diode; the other end of the second capacitor and the fifth diode are connected to the ground; the cathode of the fifth diode is connected to the other end of the first resistor, and the anode of the fifth diode is connected to the ground.

[0027] It should be noted that the protection circuit provided in the embodiments of the present application includes three charging circuits, the first charging circuit is connected to the U phase of the motor, the second charging circuit is connected to the V phase of the motor, and the third charging circuit is connected to the W phase of the motor; the second capacitors are C21, C22, and C23, the first resistors are R11, R12, and R13, the fourth diodes are D21, D22, and D23, the fifth diodes are D31, D32, and D33, and the transistors in the charging circuits are Q71, Q72, and Q73; the fourth diodes D21, D22, and D23 are voltage stabilizing diodes in the charging circuit.

[0028] In an optional implementation of the embodiments of the present application, the protection circuit provided in the embodiments of the present application is provided with two transistor integrated circuits on the bridge wall of the switch tube, and the transistor integrated circuit includes a transistor, a parasitic resistor, and a parasitic diode.

[0029] It should be noted that the parasitic diodes of Q71, Q72, and Q73 in the charging circuit are not reflected in the circuit diagram, and the connection mode is consistent with Q1.

[0030] In an optional implementation of the embodiments of the present application, the type of the transistor in the protection circuit provided in the embodiments of the present application includes an insulated gate bipolar transistor (IGBT) or a metal-oxide semiconductor field effect transistor (MOSFET).

[0031] It should be noted that in the case of using an IGBT as the transistor, the collector and the emitter of the IGBT are connected to the protection circuit, and the base of the IGBT is connected to the driving circuit; in the case of using a MOSFET as the transistor, the source and the drain of the MOSFET are connected to the protection circuit, and the gate of the MOSFET is connected to the driving circuit.

[0032] The embodiments of the present application provide a control method of a protection circuit, as shown in the accompanying drawings. Figure 4 The control method includes the following steps.

[0033] Step 402: In the case that the motor is in a stable running state, the conduction state of the transistor in the three-phase inverter circuit is obtained.

[0034] Step 404: in the case that the motor is in the state of speed reduction operation, turn off all the transistors in the three-phase inverter circuit, and determine the transistors in the on state before being turned off;

[0035] Step 406: determine the charging loop connected with the transistors in the on state before being turned off;

[0036] Step 408: in the case that the transistors in the charging loop are in the on state, charge the second capacitor in the charging loop.

[0037] It should be noted that the control method of the protection circuit provided in the present application can be applied to a washing machine, and can also be applied to other scenarios in which a motor generates a freewheeling current. In the first exemplary embodiment, the control method of the protection circuit provided in the present application is applied to a washing machine. In the case that the motor is in the state of stable operation, the transistors in the on state are Q1 and Q6, the current starts from the positive electrode of the capacitor C1, goes through the transistor Q1 to the U-phase winding of the motor, and then goes to the W-phase winding, and then goes through the transistor Q6 to the ground. In the case that the motor is in the state of speed reduction operation, all the transistors are turned off. Since the current cannot be abruptly changed, the UW generates a freewheeling current. Since the first diode D1 exists, the freewheeling current cannot charge the capacitor C1 in the reverse direction through the parasitic diodes of Q5 and Q2, thereby protecting the capacitor C1. At the same time, the transistor Q73 is in the on state, and the freewheeling loop of the motor current is: starting from the W-phase winding, going through Q73, Q23, and R13 to the second capacitor C23, and charging the second capacitor C23. In the second exemplary embodiment, in the case that the motor is in the state of speed reduction operation, the transistors in the on state are Q1, Q4, and Q6. The current starts from the capacitor C1, goes through D1 and Q1, and then divides into two paths. One path goes through the V-phase winding, i.e., Q4, to GND, and the other path goes through the W-phase winding, i.e., Q6, to GND. At this time, Q1, Q4, and Q6 are turned off. The polarities of the voltages induced by the V and W phases are positive, and the polarity of the voltage induced by the U phase is negative. At the same time, the transistors Q72 and Q73 are in the on state, and the U and W windings can charge the second capacitors C22 and C23 through Q72 and Q73. In the third exemplary embodiment, in the case that the motor is in the state of speed reduction operation, the transistors in the on state are Q3 and Q2. The current starts from the positive electrode of the capacitor C1, goes through the transistor Q3 to the V-phase winding of the motor, and then goes to the U-phase winding, and then goes through the transistor Q2 to the ground. In the case that the motor is in the state of speed reduction operation, all the transistors are turned off, and at the same time, the transistor Q72 in the charging loop is in the on state. The U and V windings can charge the second capacitor C22 through Q72.

[0038] In the optional implementation of the embodiment of the present application, the control method of the protection circuit provided in the present application is applied to the motor in the state of operation, such as Figure 5As shown, comprising:

[0039] Step 501: the motor is running;

[0040] Step 502: determine whether the motor is in a stable running state;

[0041] Step 503: in the case of the motor in a stable running state, the on-off state of the transistor in the three-phase inverter circuit is obtained;

[0042] Step 505: determine whether the motor is in a speed reduction running state;

[0043] Step 505: in the case of the motor in a speed reduction running state, all transistors Q1 to Q6 in the three-phase inverter circuit are turned off;

[0044] Step 506: determine the transistor in the three-phase inverter circuit which is in the on state before being turned off;

[0045] Step 507: determine the charging circuit corresponding to the transistor in the on state before being turned off;

[0046] Step 508: make the transistor in the corresponding charging circuit in the on state, and charge the corresponding second capacitor.

[0047] In the optional embodiment of the embodiment of the application, the control method of the protection circuit provided by the application is provided, and the charging circuit is connected with the storage battery, as shown in Figure 6 The method comprises:

[0048] Step 602: in the case that the power of the storage battery is less than the first preset threshold, the storage battery is charged based on the second capacitor in the charging circuit;

[0049] Step 604: in the case that the power of the storage battery is greater than the second preset threshold, the charging circuit is controlled to stop charging the storage battery; wherein the second preset threshold is greater than the first preset threshold.

[0050] It should be noted that the storage battery is provided with a built-in charging chip, and accepts the energy supply of the charging capacitor; the power of the storage battery can be used for power supply of the display panel, or can be used for driving the DC fan to dissipate heat when the electrical appliance is running.

[0051] In the fourth example, the control method of the protection circuit provided by the application is applied to a washing machine, the first preset threshold is 20%, and the second preset threshold is 80%, as shown in Figure 7 The method comprises:

[0052] Step 701: determine whether the power of the storage battery is less than 20%;

[0053] Step 702: in the case that the battery power is less than 20%, charging the battery based on the second capacitor in the charging loop;

[0054] Step 703: judging whether the battery power is greater than 80%;

[0055] Step 704: in the case that the battery power is greater than 80%, controlling the charging loop to stop charging the battery, cutting off the power supply circuit of the main board to the display board, and using the battery to supply power to the display board;

[0056] Judgment 705: in the case that the battery power is less than 20%, cutting off the power supply circuit of the battery to the display board and charging the battery.

[0057] In the optional implementation of the embodiment of the application, the control method of the protection circuit provided by the application comprises: in the case that the battery power is greater than the second preset threshold, using the battery to supply power to the electric appliance.

[0058] It should be noted that, in the fifth example, the power supply mode using the second capacitor is as shown in Figure 8 After the charging capacitor charges the battery, the battery power can be used to supply power to the display board of the electric appliance or to supply power to the driving direct-current fan of the electric appliance to dissipate heat.

[0059] In the optional implementation of the embodiment of the application, the control method of the protection circuit provided by the application comprises: in the case that the motor is in a stable running state, at least one transistor on the upper bridge wall and at least one transistor on the lower bridge wall are in a conductive state, and the transistor on the upper bridge wall and the transistor on the lower bridge wall of the same switch tube bridge arm cannot be conductive at the same time.

[0060] It can be seen that the control method of the protection circuit provided by the embodiment of the application can avoid reverse charging of the motor to the bus capacitor by using the unidirectional conductivity of the diode, and collect the energy of the freewheeling circuit from the charging loop, thereby solving the technical problem that the freewheeling energy in the prior art easily damages the bus capacitor.

[0061] The embodiment of the application further provides an electronic device, as shown in Figure 9 The electronic device comprises a processor 901, a communication interface 902, a memory 903 and a communication bus 904, wherein the processor 901, the communication interface 902 and the memory 903 complete mutual communication through the communication bus 904,

[0062] The memory 903 is used to store a computer program;

[0063] The processor 901 is used to execute the program stored in the memory 903 to realizeFigure 1 the method steps in Figure 1 the method steps in

[0064] The communication bus mentioned above can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, Figure 9 only one thick line is used in

[0065] The communication interface is used for communication between the terminal and other devices.

[0066] The memory can include a Random Access Memory (RAM) and can also include a non-volatile memory, such as at least one disk memory. Optionally, the memory can also be at least one storage device located away from the aforementioned processor.

[0067] The processor mentioned above can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc. It can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component.

[0068] In another embodiment provided in the present application, a computer readable storage medium is also provided, which stores instructions, and when the instructions run on a computer, the computer executes the control method of the protection circuit in any of the above embodiments.

[0069] In another embodiment provided in the present application, a computer program product containing instructions is also provided, and when the instructions run on a computer, the computer executes the control method of the protection circuit in any of the above embodiments.

[0070] In the embodiments described above, all or some of the steps can be implemented by hardware, software, firmware or any combination thereof. When implemented by software, all or some of the steps can be implemented in the form of one or more computer programs or program elements. The computer programs reside (at least temporarily) in a memory of a computer during execution. The memory can be a RAM memory, a flash memory, a ROM memory, an EPROM memory, or any other suitable memory. The memory can be integral to or separate from the computer. The computer programs can be written in any suitable programming language, such as C, C++, Java, Visual Basic, etc. The computer programs can be written in assembly or machine language, if desired. The computer programs can be distributed over network coupled file servers, or can be distributed by any other suitable means.

[0071] It is to be noted that the terms such as first and second, etc., are used herein merely to differentiate one entity or action from another, and do not necessarily require or imply any such actual relationship or order between such entities or actions. Also, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusions, such that a process, method, article, or apparatus that comprises a list of elements does not necessarily include only those elements in the list, but can include other elements not expressly listed, or can include elements inherent in such process, method, article, or apparatus.

[0072] Each of the embodiments described in the specification is described in a related manner, and the same or similar parts among the embodiments can be referred to each other. Each of the embodiments focuses on the difference from other embodiments. In particular, the system embodiments are described in a relatively simple manner, since they are substantially similar to the method embodiments, and the relevant parts can be referred to the description of the method embodiments.

[0073] The above merely provides the preferred embodiments of the application, and not intended to limit the protection scope of the application. Any modification, equivalent replacement, improvement, and the like made within the principle and technical scope of the application shall fall into the protection scope of the application.

Claims

1. A protection circuit, characterized by, The application relates to a three-phase inverter circuit, a first diode, a second diode, a third diode and a charging circuit; wherein the three-phase inverter circuit comprises a first capacitor, a motor and three switch tube bridge walls; two transistors are arranged on each of the switch tube bridge walls; the first end and the second end of the transistor are connected to the three-phase inverter circuit, and the third end of the transistor is connected to a transistor driving circuit; the cathode of the first diode is connected to the first end of the transistor on the upper tube bridge wall of the switch tube bridge wall, and the anode of the first diode is connected to the positive pole of the first capacitor; the anode of the second diode is connected to the second end of the transistor on the lower tube bridge wall of the switch tube bridge wall, and the cathode of the second diode is connected to the negative pole of the first capacitor; the third diode is connected in parallel with the second diode and the transistor on the lower tube bridge wall of the switch tube bridge wall and then grounded; the three phases of the motor are respectively connected to the three common ends of the upper and lower tube bridge walls of the three switch tube bridge walls one by one, and each phase of the motor is connected to one charging circuit; wherein the charging circuit comprises a second capacitor, a first resistor, a fourth diode, a fifth diode and a transistor, wherein the first end of the transistor in the charging circuit is connected to the motor, the second end of the transistor in the charging circuit is connected to the anode of the fourth diode, the third end of the transistor in the charging circuit is connected to the driving circuit of the transistor in the charging circuit; the cathode of the fourth diode is connected to one end of the first resistor, the second capacitor and the fifth diode are connected in parallel, one end of the second capacitor and the fifth diode is connected to the other end of the first resistor, and the other end of the second capacitor and the fifth diode is connected to the ground; the cathode of the fifth diode is connected to the other end of the first resistor, and the anode of the fifth diode is connected to the ground. Two transistor integrated circuits are arranged on the switch tube bridge wall, and the transistor integrated circuit comprises a transistor, a parasitic resistor and a parasitic diode.

2. The circuit of claim 1, wherein, The type of transistor comprises an insulated gate bipolar transistor (IGBT) or a metal-oxide semiconductor field effect transistor (MOSFET).

3. The circuit of claim 1, wherein, The application relates to a method for controlling the charging circuit of a three-phase inverter circuit.

4. A control method of a protection circuit according to any one of claims 1 to 3, characterized by, In the case that the motor is in a stable running state, the conduction state of the transistor in the three-phase inverter circuit is acquired; in the case that the motor is in a speed reduction running state, all the transistors in the three-phase inverter circuit are turned off, and the transistor in the conduction state before being turned off is determined; the charging circuit connected to the transistor in the conduction state before being turned off is determined; in the case that the transistor in the charging circuit is in the conduction state, the second capacitor in the charging circuit is charged. The charging circuit is connected to a storage battery, and the method comprises:

5. The method of claim 4, wherein, in the case that the electric quantity of the storage battery is less than a first preset threshold value, the storage battery is charged based on the second capacitor in the charging circuit; in the case that the electric quantity of the storage battery is greater than a second preset threshold value, the charging of the storage battery by the charging circuit is controlled to be stopped; wherein the second preset threshold value is greater than the first preset threshold value. The method comprises:

6. The method of claim 5, wherein, ​ In the case that the battery power is greater than the second preset threshold, the battery is used to supply power to the electrical device.

7. The method of claim 4, wherein, In the case that the motor is in a stable running state, at least one transistor on the upper bridge wall and at least one transistor on the lower bridge wall are in a conducting state, and the transistor on the upper bridge wall and the transistor on the lower bridge wall of the same switch bridge arm cannot be in a conducting state at the same time.

8. An electronic device, comprising: The device comprises a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; The memory is used for storing a computer program. The processor is used for executing the program stored on the memory to realize the method steps in any one of claims 4-7.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the method steps in any one of claims 4-7.

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