An overcurrent protection device of a motor, a motor and an overcurrent protection method thereof

Abstract

The application discloses an overcurrent protection device of a motor, the motor and an overcurrent protection method of the motor. The device comprises a sampling unit, which samples three-phase electric parameters of the motor; a hardware protection unit, which compares the three-phase electric parameters of the motor with preset electric parameters, and if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, controls the motor to stop from the hardware, and sends a first overcurrent fault signal that the motor has an overcurrent fault; and a software protection unit, which, under the condition of receiving the first overcurrent fault signal, converts the first overcurrent fault signal into a brake protection signal, and according to the brake protection signal, cuts off the control signal of the motor, controls the motor to stop from the software, sends a second overcurrent fault signal that the motor has an overcurrent fault, and realizes the cooperative overcurrent protection of the motor. The scheme can achieve the purpose of the cooperative overcurrent protection of the software and the hardware, is timely in protection, and is simple in implementation and low in cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric machines, in particular to an overcurrent protection device of an electric machine, an electric machine and an overcurrent protection method thereof, and especially to an overcurrent protection device of a permanent magnet synchronous electric machine, an electric machine and an overcurrent protection method thereof. BACKGROUND

[0002] With the mature development of the technology in the field of household appliances and the rapid advancement of power electronics technology, permanent magnet synchronous electric machines are increasingly popular due to their high efficiency and low noise. However, the stability and reliability of the overcurrent protection method are the key safety guarantees for the normal operation of permanent magnet synchronous electric machines. In related solutions, the overcurrent protection method relies on a single hardware or software program to achieve overcurrent protection. However, the single hardware implementation of overcurrent protection has the problems of complex process and high cost, and the single software program implementation of overcurrent protection has the problems of complex algorithm and delayed protection.

[0003] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0004] The purpose of the present application is to provide an overcurrent protection device of an electric machine, an electric machine and an overcurrent protection method thereof, to solve the problem that in related solutions, the overcurrent protection method for electric machines (such as permanent magnet synchronous electric machines) relies on a single hardware or software program to achieve overcurrent protection. However, the single hardware implementation of overcurrent protection has the problems of complex process and high cost, and the single software program implementation of overcurrent protection has the problems of complex algorithm and delayed protection. The present application achieves the effect of timely protection and simple implementation and low cost by adopting a hardware overcurrent protection method and a software overcurrent protection method in cooperation.

[0005] The present application provides an overcurrent protection device of an electric machine, comprising: a sampling unit, a hardware protection unit and a software protection unit; wherein the sampling unit is configured to sample three-phase electrical parameters of the electric machine; the hardware protection unit is configured to compare the three-phase electrical parameters of the electric machine with preset electrical parameters, and if the three-phase electrical parameters of the electric machine are greater than or equal to the preset electrical parameters, the hardware protection unit controls the electric machine to shut down and sends a first overcurrent fault signal indicating that the electric machine has an overcurrent fault; the software protection unit is configured to convert the first overcurrent fault signal into a brake protection signal when receiving the first overcurrent fault signal, and to shut down the control signal of the electric machine according to the brake protection signal to control the electric machine to shut down from the software, and to send a second overcurrent fault signal indicating that the electric machine has an overcurrent fault, thereby achieving cooperative overcurrent protection of the electric machine.

[0006] In some embodiments, the three-phase electrical parameter of the motor is a total three-phase current of the motor, or a voltage converted from the total three-phase current of the motor; the sampling unit comprises a current sampling module; the sampling unit samples the three-phase electrical parameter of the motor, including: the current sampling module samples the total three-phase current of the motor; or the current sampling module samples the total three-phase current of the motor and converts the total three-phase current of the motor into a corresponding voltage.

[0007] In some embodiments, the hardware protection unit comprises a comparison module and a driving module; wherein the hardware protection unit compares the three-phase electrical parameter of the motor with a preset electrical parameter, and if the three-phase electrical parameter of the motor is greater than or equal to the preset electrical parameter, the hardware protection unit controls the motor to shut down and sends a first overcurrent fault signal that the motor has an overcurrent fault, including: the comparison module is configured to compare the three-phase electrical parameter of the motor with a preset electrical parameter, and if the three-phase electrical parameter of the motor is greater than or equal to the preset electrical parameter, the comparison module outputs a first level signal; the driving module is configured to turn off a power switch tube in the driving module based on the first level signal and output a second level signal as the first overcurrent fault signal that the motor has an overcurrent fault.

[0008] In some embodiments, the comparison module comprises an operational amplifier.

[0009] In some embodiments, the driving module comprises an IPM driving module; the power switch tube in the IPM driving module comprises an IGBT.

[0010] In some embodiments, the software protection unit comprises a pull-up module and a control module; the software protection unit converts the first overcurrent fault signal into a brake protection signal when receiving the first overcurrent fault signal, and turns off a control signal of the motor according to the brake protection signal to control the motor to shut down from software and send a second overcurrent fault signal that the motor has an overcurrent fault, thereby achieving cooperative overcurrent protection of the motor, including: the pull-up module is configured to convert the first overcurrent fault signal into a brake protection signal when receiving the first overcurrent fault signal; the control module is configured to turn off the control signal of the motor according to the brake protection signal to control the motor to shut down from software and send the second overcurrent fault signal that the motor has an overcurrent fault, thereby achieving cooperative overcurrent protection of the motor.

[0011] In some embodiments, the pull-up module further provides a power supply voltage for the hardware protection unit; wherein the pull-up module comprises a 3.3V pull-up module; in the case that the hardware protection unit comprises a comparison module and a driving module, the 3.3V pull-up module provides a power supply voltage for the comparison module.

[0012] In order to match the above-mentioned device, the application further provides a motor, comprising the over-current protection device of the motor as described above.

[0013] In order to match the above-mentioned motor, the application further provides an over-current protection method of a motor, comprising: sampling three-phase electric parameters of the motor by the sampling unit; comparing the three-phase electric parameters of the motor with preset electric parameters by the hardware protection unit, if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, then controlling the motor to stop from the hardware, and sending a first over-current fault signal that the motor has an over-current fault; converting the first over-current fault signal into a brake protection signal by the software protection unit in the case that the first over-current fault signal is received, and shutting down the control signal of the motor according to the brake protection signal, so as to control the motor to stop from the software, and sending a second over-current fault signal that the motor has an over-current fault, thereby realizing the cooperative over-current protection of the motor.

[0014] Therefore, the scheme of the application triggers the hardware protection, i.e. shuts down the IGBT in the IPM driving module, when the motor has an over-current, at the same time, converts the over-current fault signal output by the IPM driving module through the 3.3V pull-up module and inputs the brake protection pin of the control chip of the motor controller, and then starts the software protection, i.e. shuts down the PWM signal of the IPM driving module through the control chip module, so as to realize the over-current protection of the motor from the hardware and the software, thereby, through the motor over-current protection strategy of the cooperative hardware over-current protection mode and software over-current protection mode, the double protection purpose of the cooperative over-current protection of the hardware and the software can be achieved, the protection is timely, and the implementation mode is simple and the cost is low.

[0015] Other features and advantages of the application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the application.

[0016] The technical scheme of the application will be further described in detail below with the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a structural schematic diagram of an embodiment of the over-current protection device of the motor of the application;

[0018] Figure 2 Structure schematic diagram of an embodiment of a permanent magnet synchronous motor overcurrent protection circuit;

[0019] Figure 3 Implementation flow schematic diagram of an embodiment of an overcurrent protection method of the present application;

[0020] Figure 4 Implementation flow schematic diagram of an embodiment of a permanent magnet synchronous motor overcurrent protection scheme. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in connection with specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] It is considered that in the related scheme, the overcurrent protection mode of the motor (such as a permanent magnet synchronous motor) is achieved by relying on a single hardware or software program. Among them, the single hardware overcurrent protection implementation mode is achieved by combining a voltage dividing circuit and a comparator circuit, and the fault output end is pulled up to 15V, which cannot be directly connected with the pin of the single-chip microcomputer. When actually applied, an additional circuit needs to be added, resulting in complex process and high cost. Because the general chip supply voltage is 3.3V, 15V cannot directly power the chip, and needs to be realized by adding a hardware circuit (such as a DC-DC circuit). At the same time, in order to ensure that the control chip module can be effectively protected and the chip can stop normal output control signal, more external protection circuits (such as comparator circuits) need to be added, which has high implementation cost and increases circuit complexity, which is a defect of this single hardware protection mode. The single software overcurrent protection needs to use complex algorithms, which may not protect in time and cause the motor (such as a permanent magnet synchronous motor) to burn. Therefore, the scheme of the present application provides a permanent magnet synchronous motor overcurrent protection scheme to solve the problem that the overcurrent protection mode of the motor (such as a permanent magnet synchronous motor) only relies on a single hardware or software program to achieve overcurrent protection.

[0023] According to the embodiments of the present application, an overcurrent protection device of a motor is provided. Referring to Figure 1 the structure schematic diagram of an embodiment of the device of the present application. The motor has a power driving unit. The overcurrent protection device of the motor comprises a sampling unit, a hardware protection unit and a software protection unit. The sampling unit, the hardware protection unit and the software protection unit are connected in sequence.

[0024] Among them, the sampling unit is configured to sample three-phase electrical parameters of the motor.

[0025] In some embodiments, the three-phase electrical parameters of the motor are the total three-phase current of the motor, or the voltage obtained by converting the total three-phase current of the motor.

[0026] The sampling unit includes a current sampling module. The sampling unit samples the three-phase electrical parameters of the motor, including: the current sampling module sampling the total three-phase current of the motor; or, the current sampling module sampling the total three-phase current of the motor and converting the total three-phase current of the motor into a corresponding voltage.

[0027] Figure 2 This is a schematic diagram of one embodiment of an overcurrent protection circuit for a permanent magnet synchronous motor. Figure 2 As shown, the present invention designs a novel, low-cost overcurrent protection method combining hardware and software. The main circuit in this overcurrent protection method, namely the permanent magnet synchronous motor overcurrent protection circuit, includes a current sampling module. This current sampling module uses a current acquisition circuit to amplify and filter the U, V, and W phase currents of the motor to obtain the total three-phase current.

[0028] The hardware protection unit is configured to compare the three-phase electrical parameters of the motor with preset electrical parameters. If the three-phase electrical parameters of the motor are greater than or equal to the preset electrical parameters, the unit controls the motor to stop from the hardware and issues a first overcurrent fault signal indicating that the motor has an overcurrent fault.

[0029] In some implementations, the hardware protection unit includes a comparison module and a driver module, wherein the comparison module is such as a comparison circuit module and the driver module is such as an IPM driver module.

[0030] The hardware protection unit compares the three-phase electrical parameters of the motor with preset electrical parameters. If the three-phase electrical parameters of the motor are greater than or equal to the preset electrical parameters, the unit controls the motor to stop via hardware and issues a first overcurrent fault signal indicating an overcurrent fault in the motor, including:

[0031] The comparison module is configured to compare the three-phase electrical parameters of the motor with preset electrical parameters. If the three-phase electrical parameters of the motor are greater than or equal to the preset electrical parameters, a first level signal (such as a high-level signal) is output. Optionally, the comparison module includes an operational amplifier.

[0032] The driving module is configured to turn off a power switch tube in the driving module based on the first level signal, and output a second level signal (such as a low level signal) as a first overcurrent fault signal of the motor appearing overcurrent fault. Optionally, the driving module comprises an IPM driving module.

[0033] As shown in Figure 2 The scheme of the application designs a new low-cost software and hardware combined overcurrent protection mode, and the main circuit, i.e., the permanent magnet synchronous motor overcurrent protection circuit, further comprises a comparison circuit module and an IPM driving module.

[0034] The three-phase total current sampled by the current sampling module is input into the subsequent comparison circuit module. The comparison circuit module is provided with a maximum protection current Imax. The output end of the comparison circuit module is connected to a CSC pin (i.e., a short-circuit current sensing input pin) of the IPM driving module.

[0035] The software protection unit is configured to convert the first overcurrent fault signal into a brake protection signal when the first overcurrent fault signal is received, and turn off the control signal of the motor according to the brake protection signal to control the motor to stop from the software, and output a second overcurrent fault signal of the motor appearing overcurrent fault, so as to realize the cooperative overcurrent protection of the motor.

[0036] The scheme of the application proposes a permanent magnet synchronous motor overcurrent protection scheme, which adopts a control strategy of cooperative hardware overcurrent protection and software overcurrent protection of the permanent magnet synchronous motor, i.e., when overcurrent protection occurs, the hardware responds to the first priority circuit to start to act, and the fault signal is given to the control chip module of the permanent magnet synchronous motor controller, at this time, the software starts the second priority response, so as to achieve the purpose of cooperative overcurrent protection of the hardware and software, and solve the problem of the overcurrent protection mode of the motor (such as the permanent magnet synchronous motor) relying on only single hardware or software program to realize overcurrent protection. The overcurrent protection scheme designed by the scheme of the application is a cooperative permanent magnet synchronous motor overcurrent protection scheme of the hardware first priority response and the software second priority response, and has low cost and high reliability.

[0037] For example, in the related scheme, the single hardware overcurrent protection circuit is realized by using the combination of double voltage dividing circuits and double comparator circuits, the circuit design is complex, the cost is high, the fault output end is pulled up to 15V, cannot be directly connected with the single chip microcomputer pin in actual application, and an additional circuit needs to be added, therefore, it is not conducive to production, and the realization is complex.The scheme of the present application designs a new type of overcurrent detection and protection circuit, the hardware circuit is simple, software and hardware cooperative protection can be formed through sampling comparison, IPM hardware and chip peripheral circuit connection, and the protection reliability is higher.

[0038] In some embodiments, the software protection unit comprises a pull-up module and a control module, the pull-up module is, for example, a 3.3V pull-up module, and the control module is, for example, a control chip module.

[0039] In the case that the software protection unit receives the first overcurrent fault signal, the software protection unit converts the first overcurrent fault signal into a brake protection signal, and according to the brake protection signal, the control signal of the motor is turned off to control the motor to stop from the software, and a second overcurrent fault signal that the motor has an overcurrent fault is sent, and cooperative overcurrent protection of the motor is realized, including:

[0040] The pull-up module is configured to convert the first overcurrent fault signal into a brake protection signal in the case that the pull-up module receives the first overcurrent fault signal.

[0041] The control module is configured to turn off the control signal of the motor according to the brake protection signal to control the motor to stop from the software, and send a second overcurrent fault signal that the motor has an overcurrent fault to realize cooperative overcurrent protection of the motor.

[0042] As Figure 2 shown, the scheme of the present application designs a new type of low-cost overcurrent protection mode combining software and hardware, in which the main circuit, i.e., the permanent magnet synchronous motor overcurrent protection circuit, further comprises a 3.3V pull-up module and a control chip module.

[0043] The VFO pin (i.e., the fault output alarm pin of the IPM) of the IPM driving module is connected to the input end of the 3.3V pull-up module. The output end of the 3.3V pull-up module is connected to the PC3 pin (i.e., the brake protection pin) of the control chip module. The output end of the control chip module can output a control signal for turning off the PWM to the control end of the IPM driving module.

[0044] Optionally, the pull-up module further provides a power supply voltage for the hardware protection unit; wherein the pull-up module comprises a 3.3V pull-up module; in the case that the hardware protection unit comprises a comparison module and a driving module, the 3.3V pull-up module provides a power supply voltage for the comparison module.

[0045] In Figure 2 In the example shown, the comparison circuit module and the IPM driving module constitute a first priority protection part, and the 3.3V pull-up module and the control chip module constitute a second priority protection part.

[0046] It should be noted that in the overcurrent protection circuit of the permanent magnet synchronous motor, the power supply pin of the operational amplifier in the comparison circuit module is connected to the 3.3V pull-up module, so as to use the 3.3V pull-up module to supply power to the operational amplifier. The VFO pin of the PM driving module must be connected to the 3.3V pull-up module, so as to convert the output signal of the VFO pin of the IPM driving module into a signal that can be received by the control chip module, to ensure that the hardware overcurrent fault triggers, the control chip receives the signal to trigger the software protection at the same time, to achieve the effect of cooperative protection, and to ensure the reliability of the circuit. The use of the IPM driving module for overcurrent protection can save circuit components, and the use of the 3.3V pull-up module to supply power to the operational amplifier in the comparison circuit module can further save circuit components, reduce the complexity of the circuit, and save costs.

[0047] By using the IPM driving module and the 3.3V pull-up module of the motor, the hardware protection is triggered when the motor overflows, that is, the IGBT in the IPM driving module is turned off, and the overcurrent fault signal output by the IPM driving module is converted by the 3.3V pull-up module and input into the brake protection pin of the control chip of the motor controller, and then the software protection is started, that is, the PWM signal of the IPM driving module is turned off through the control chip module, so as to realize overcurrent protection of the motor from both hardware and software, so that the motor overcurrent protection strategy of the hardware overcurrent protection mode and the software overcurrent protection mode is adopted, the dual protection purpose of the hardware and software cooperative overcurrent protection is achieved, the protection is timely, and the implementation is simple and low in cost.

[0048] According to the embodiments of the present application, a motor corresponding to the overcurrent protection device of the motor is also provided. The motor can comprise the overcurrent protection device of the motor described above.

[0049] Since the processing and functions realized by the motor of the present embodiment are basically corresponding to the embodiments, principles and examples of the device, the description of the present embodiment will not be described in detail, and the relevant description in the foregoing embodiments can be referred to, which will not be described herein.

[0050] The technical scheme of the application utilizes the IPM driving module and the 3.3V pull-up module of the motor, triggers the hardware protection, i.e. turns off the IGBT in the IPM driving module when overcurrent occurs in the motor, converts the overcurrent fault signal output by the IPM driving module through the 3.3V pull-up module and inputs the converted signal into the brake protection pin of the control chip of the motor controller, and then starts the software protection, i.e. turns off the PWM signal of the IPM driving module through the control chip module, so as to realize the overcurrent protection of the motor from the hardware and the software, and achieve the purpose of the overcurrent protection of the software and the hardware.

[0051] According to the embodiment of the application, an overcurrent protection method of a motor corresponding to the motor is also provided, as shown in Figure 3 The embodiment flowchart of the method of the application is shown in the figure. The overcurrent protection method of the motor can include steps S110 to S130.

[0052] In step S110, the sampling unit samples the three-phase electric parameters of the motor.

[0053] In step S120, the hardware protection unit compares the three-phase electric parameters of the motor with the preset electric parameters, and if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, the motor is controlled to stop from the hardware, and a first overcurrent fault signal that the motor has an overcurrent fault is sent.

[0054] In step S130, the software protection unit converts the first overcurrent fault signal into a brake protection signal and turns off the control signal of the motor according to the brake protection signal to control the motor to stop from the software when the first overcurrent fault signal is received, sends a second overcurrent fault signal that the motor has an overcurrent fault, and realizes the cooperative overcurrent protection of the motor.

[0055] Specifically, Figure 4 The embodiment flowchart of the overcurrent protection scheme of the permanent magnet synchronous motor is shown in the figure. Figure 4 As shown in the figure, the overcurrent protection scheme of the permanent magnet synchronous motor includes:

[0056] Step 1: After the initialization of the motor controller is completed, the AD sampling switch of the motor controller is turned on, the parameters required for the normal operation of the motor, such as the bias voltage and the bus voltage, are collected, and when all the parameters are within the normal error range, the state of the motor controller is switched to the ready-to-run state.

[0057] Step 2, after entering the ready-to-run state, if this start is the first start of the motor, the state of the motor controller will be switched to detect whether the overcurrent protection state is triggered: if the overcurrent protection state is not triggered, the state of the motor controller is switched to the running state. When the overcurrent protection state is triggered, that is, when the total current of the three-phase obtained by sampling the current sampling module exceeds the maximum protection current Imax, the output pin of the comparison circuit module of the permanent magnet synchronous motor overcurrent protection circuit is input to the CSC pin of the IPM drive module. The input signal of the IPM drive module is high (that is, the positive input voltage of the operational amplifier in the comparison circuit module exceeds the maximum protection current setting threshold), at this time the hardware first priority protection response is started immediately, the IGBT inside the IPM drive module is turned off, and the overcurrent protection fault is reported. Specifically, the sampling resistor and the three-phase of the motor are connected, that is, the voltage across the sampling resistor is the size of the phase current of the motor. This method can be converted to a voltage value input to the comparison circuit module, and after amplification by the operational amplifier of the comparison circuit module, it is compared with the set protection threshold.

[0058] At the same time, the signal output by the VFO pin of the IPM drive module is low as a voltage. The VFO pin of the IPM drive module is connected to the brake protection pin (i.e. PC3 pin) of the control chip module after passing through the 3.3V pull-up module. When the PC3 pin of the control chip module detects that the VFO pin of the IPM drive module is low, the software starts the second priority protection response at this time, immediately turns off the PWM signal output to the IPM drive module, and changes the motor running state (i.e. controls the motor to stop running), enters the overcurrent protection interrupt, and reports the overcurrent protection fault.

[0059] Among them, under the condition that the hardware first protection outputs the first overcurrent fault signal, the motor is switched to the overcurrent protection state, and the signal is converted to the brake protection signal to further switch to the overcurrent protection state; the motor stops running, and the fault signal means the stoppage fault signal fed back by the motor interface to the terminal product mainboard.

[0060] In the above embodiment, Figure 4The embodiment flowchart diagram of the shown embodiment of the permanent magnet synchronous motor overcurrent protection scheme is specifically an entire process flowchart of overcurrent protection detection and triggering corresponding protection for the appearing overcurrent phenomenon when the motor controller runs each time.When the motor controller initialization is completed, AD sampling is opened, the bias voltage, bus voltage and other parameters required for the normal operation of the motor are collected, the controller state is switched to the preparation running state when all the parameters are within the normal error range, the controller state is switched to the detection whether the overcurrent protection is triggered state if the motor is started for the first time after entering the preparation running state, otherwise, the controller state is switched to the running state.When the controller state enters the detection whether the overcurrent protection is triggered state, whether the first priority hardware protection is triggered is judged preferentially, the first priority hardware protection is directly triggered if it is judged that the overcurrent is triggered, the controller state is switched to the overcurrent protection state, the motor stops running and the corresponding fault signal is sent.Meanwhile, the second priority software protection is triggered, the controller state is switched to the overcurrent protection state, the motor stops running and the corresponding fault signal is sent.

[0061] The first hardware protection makes the IGBT in the IPM module be instantaneously turned off, so that the damage caused by the instantaneous overcurrent of the direct current motor is avoided; and the second priority software protection is to avoid that the PWM control signal output by the chip is not turned off in time and continuously after the module is instantaneously stopped, so that the IGBT is instantaneously protected and then the motor is started again to trigger the overcurrent again.

[0062] The scheme of the application relates to a kind of overcurrent protection methods of permanent magnet synchronous motor, specifically a kind of overcurrent protection method of permanent magnet synchronous motor controller, especially to a kind of intelligent power module (IPM) with fault output function, the pin of the IPM has fault output function, can detect and output overcurrent and the like fault.The hardware of IPM drive module and the software program control of the control chip module of motor controller can effectively guarantee the reliable operation of motor and motor driver.When there is overcurrent signal, i.e. the three-phase total current of motor collected exceeds the set threshold, then the first priority response of hardware circuit is started, and the IGBT of IPM drive module is turned off.At this time, the VFO pin of IPM (i.e. the fault output alarm pin of IPM) carries out fault output (such as the digital signal output is low level), and the PC3 pin of control chip module collects low level at this time and starts the second priority response, and the PWM output of control chip module (such as single-chip microcomputer) is turned off, to achieve the purpose of overcurrent protection of software and hardware cooperation.

[0063] The IGBT of IPM drive module is turned off, specifically through CSC pin connection module internal front driver chip, and the front driver chip is received controller chip PWM signal to control IGBT conduction or turn off, once CSC input signal high level is input to front driver chip, i.e. front driver chip is locked, cannot normally work, i.e. IGBT cannot normally open work, plays the role of hardware protection.

[0064] Since the processing and functions realized by the method of the embodiment are basically corresponding to the foregoing embodiments, principles and examples of the motor, the unexplained parts in the description of the embodiment can be seen in the foregoing related descriptions of the embodiments, which will not be repeated here.

[0065] By using the IPM driving module and the 3.3V pull-up module of the motor, the IGBT in the IPM driving module is turned off when the motor overflows, and the overcurrent fault signal output by the IPM driving module is converted by the 3.3V pull-up module and input into the brake protection pin of the control chip of the motor controller, and then the software protection is started, that is, the PWM signal of the IPM driving module is turned off by the control chip module, so as to realize the overcurrent protection of the motor from the hardware and the software, realize the permanent magnet synchronous motor overcurrent protection scheme of the hardware first priority response and the software second priority response cooperation, and is easy to realize and low in cost.

[0066] In summary, those skilled in the art can easily understand that the above-mentioned advantageous modes can be freely combined and superimposed without conflict.

[0067] The above only describes the embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the scope of claims of the present application.

Claims

1. An overcurrent protection device for an electric machine, characterized in that The motor protection device comprises: a sampling unit, a hardware protection unit and a software protection unit; wherein, the sampling unit is configured to sample three-phase electric parameters of the motor; the hardware protection unit is configured to compare the three-phase electric parameters of the motor with preset electric parameters, and if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, to control the motor to stop from the hardware aspect, and to send a first overcurrent fault signal that the motor has an overcurrent fault; the software protection unit is configured to, in the case of receiving the first overcurrent fault signal, convert the first overcurrent fault signal into a brake protection signal, and to shut off a control signal of the motor according to the brake protection signal, to control the motor to stop from the software aspect, and to send a second overcurrent fault signal that the motor has an overcurrent fault, to realize cooperative overcurrent protection of the motor; by using an IPM driving module and a 3.3V pull-up module of the motor, in the case of an overcurrent of the motor, triggering hardware protection, i.e. shutting off IGBT in the IPM driving module, and at the same time converting the overcurrent fault signal output by the IPM driving module through the 3.3V pull-up module and inputting the converted signal into a brake protection pin of a control chip of a motor controller, and then starting software protection, i.e. shutting off a PWM signal of the IPM driving module through the control chip module, to realize overcurrent protection of the motor from both hardware and software aspects.

2. The overcurrent protection device of an electric machine according to claim 1, characterized in that The three-phase electric parameters of the motor are three-phase total currents of the motor, or voltages converted from the three-phase total currents of the motor. The sampling unit comprises a current sampling module. The sampling unit samples the three-phase electric parameters of the motor, comprising: The current sampling module samples the three-phase total currents of the motor, or samples the three-phase total currents of the motor and converts the three-phase total currents of the motor into corresponding voltages.

3. Overcurrent protection device for an electric machine according to claim 1 or 2, characterized in that The hardware protection unit comprises a comparison module and a driving module; wherein, The hardware protection unit compares the three-phase electric parameters of the motor with preset electric parameters, and if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, controls the motor to stop from the hardware aspect, and sends a first overcurrent fault signal that the motor has an overcurrent fault, comprising: The comparison module is configured to compare the three-phase electric parameters of the motor with preset electric parameters, and if the three-phase electric parameters of the motor are greater than or equal to the preset electric parameters, outputs a first level signal; The driving module is configured to, based on the first level signal, shut off a power switch tube in the driving module, and outputs a second level signal as the first overcurrent fault signal that the motor has an overcurrent fault.

4. An overcurrent protection device for an electric machine according to claim 3, characterized in that The comparison module comprises an operational amplifier.

5. The overcurrent protection device for an electric machine according to claim 3, characterized in that, The driving module comprises an IPM driving module; the power switch tube in the IPM driving module comprises an IGBT.

6. An overcurrent protection device for an electric machine according to any one of claims 1 to 5, characterized in that, The software protection unit comprises a pull-up module and a control module; The software protection unit, in the case of receiving the first overcurrent fault signal, converts the first overcurrent fault signal into a brake protection signal, and according to the brake protection signal, turns off the control signal of the motor to control the motor to stop from the software, and sends a second overcurrent fault signal that the motor has an overcurrent fault, and realizes the cooperative overcurrent protection of the motor, comprising: The pull-up module is configured to convert the first overcurrent fault signal into a brake protection signal in the case of receiving the first overcurrent fault signal. The control module is configured to turn off the control signal of the motor according to the brake protection signal to control the motor to stop from the software, and send a second overcurrent fault signal that the motor has an overcurrent fault, and realize the cooperative overcurrent protection of the motor.

7. An overcurrent protection device for an electric machine according to claim 6, characterized in that The pull-up module also provides a power supply voltage for the hardware protection unit. The pull-up module includes a 3.3V pull-up module, and in the case that the hardware protection unit includes a comparison module and a driving module, the 3.3V pull-up module provides a power supply voltage for the comparison module.

8. An electric machine characterized by Comprising: The overcurrent protection device of the motor according to any one of claims 1 to 7.

9. A method of overcurrent protection for an electric machine as claimed in claim 8, characterized in that, Comprising: Through the sampling unit, the three-phase electrical parameters of the motor are sampled; Through the hardware protection unit, the three-phase electrical parameters of the motor are compared with the preset electrical parameters, and if the three-phase electrical parameters of the motor are greater than or equal to the preset electrical parameters, the motor is controlled to stop from the hardware, and a first overcurrent fault signal that the motor has an overcurrent fault is sent; Through the software protection unit, in the case of receiving the first overcurrent fault signal, the first overcurrent fault signal is converted into a brake protection signal, and according to the brake protection signal, the control signal of the motor is turned off to control the motor to stop from the software, and a second overcurrent fault signal that the motor has an overcurrent fault is sent, and the cooperative overcurrent protection of the motor is realized.

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