Safety control method and safety control system for motor controller, and storage medium

Abstract

A safety control method for a motor controller, comprising the following steps: acquiring a back electromotive force value and a bus voltage value of a motor, and comparing the back electromotive force value of the motor with the bus voltage value; in response to the back electromotive force value of the motor being less than the bus voltage value, executing a first safety control strategy; and in response to the back electromotive force value of the motor being greater than or equal to the bus voltage value, executing a second safety control strategy, and selectively switching to the first safety control strategy on the basis of a comparison between a current value of the motor and a current threshold during execution of the second safety control strategy. The present application can realize safety control of a motor in a full speed range, and reduce the risk of motor overheating and rotor magnetic steel demagnetization caused by transient current caused by ASC, thereby improving the safety performance of a motor controller. The present application further relates to a safety control system for a motor controller and a computer storage medium.

Description

Safety control method, safety control system and storage medium for motor controller Technical Field

[0001] The present application relates to the field of motor control, and more specifically to a safety control method for a motor controller, a safety control system for a motor controller, and a computer storage medium. Background Art

[0002] In electric vehicles, the proper operation of the electric drive system, comprised of the motor and motor controller, is crucial. The motor controller controls the motor to operate according to a set direction, speed, angle, response time, and other parameters. A failure in the electric drive system can damage components and even affect vehicle control. For example, when a vehicle is traveling at high speeds, excessive back EMF (back EMF) is generated at the three-phase terminals of the motor. The resulting braking torque can affect vehicle control and potentially cause battery overcharge. Furthermore, when this excessive back EMF is rectified to the DC capacitor within the controller, it raises the DC bus voltage, posing a risk of damaging power components.

[0003] Therefore, in the event of a fault in the electric drive system, active safety control measures need to be taken. Currently, common active safety control measures include active short circuit discharge (ASC) and safety pulse off (SPO).

[0004] However, the aforementioned ASC and SPO cannot guarantee the safe operation of the motor controller. For example, when all three phases of a motor enter ASC simultaneously, the stator voltage changes suddenly, and the internal winding current undergoes a transition from transient to steady-state. The superposition of transient and steady-state currents produces a large current surge. The resulting current surge in the motor's stator windings can cause motor overheating, increasing the risk of inverter damage and demagnetization of the rotor magnets. When the motor's back EMF exceeds the bus voltage, SPO will cause uncontrolled rectification, potentially affecting the DC power supply and creating the risk of overcharging.

[0005] Summary of the Invention

[0006] In order to solve or at least alleviate one or more of the above problems, the following technical solutions are provided.

[0007] According to the first aspect of the present application, a safety control method for a motor controller is provided, the method comprising the following steps: obtaining the back electromotive force value and bus voltage value of the motor and comparing the back electromotive force value of the motor with the bus voltage value; executing a first safety control strategy in response to the back electromotive force value of the motor being less than the bus voltage value; and executing a second safety control strategy in response to the back electromotive force value of the motor being greater than or equal to the bus voltage value; wherein during the execution of the second safety control strategy, the first safety control strategy is selectively switched to based on the comparison between the current value of the motor and a current threshold.

[0008] According to the safety control method of the motor controller described in one embodiment of the present application, obtaining the back electromotive force value of the motor includes: obtaining the magnetic flux and speed of the motor rotor at the current temperature; and obtaining the back electromotive force value of the motor based on the product of the magnetic flux and the speed of the motor rotor.

[0009] According to the safety control method of the motor controller described in one embodiment of the present application or any one of the above embodiments, the first safety control strategy includes a safety pulse shutdown operation, and the second safety control strategy includes a switching control operation between an active short-circuit operation and a safety pulse shutdown operation.

[0010] According to the safety control method of the motor controller described in one embodiment of the present application or any one of the above embodiments, the safety pulse shutdown operation includes: controlling each power device in the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in a disconnected state.

[0011] According to the safety control method of the motor controller described in one embodiment or any one of the above embodiments of the present application, the active short-circuit operation includes: controlling the power device of one of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in the on state, and controlling the power device of the other of the upper bridge arm and the lower bridge arm to be in the off state.

[0012] According to the safety control method of the motor controller described in one embodiment or any one of the above embodiments of the present application, the switching control operation between the active short-circuit operation and the safety pulse shutdown operation includes: controlling the power device of one of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to remain in the disconnected state; and controlling the power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in the on state with a variable duty cycle.

[0013] According to the safety control method of the motor controller described in one embodiment or any one of the above embodiments of the present application, controlling the power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in the on state with a variable duty cycle includes: controlling the power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in the on state with a variable duty cycle that gradually increases from a preset initial duty cycle to a maximum duty cycle, so that when the variable duty cycle increases to the maximum duty cycle, the power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller is controlled to remain in the on state.

[0014] According to the safety control method of the motor controller described in one embodiment or any one of the above embodiments of the present application, selectively switching to the first safety control strategy based on the comparison between the current value of the motor and the current threshold during the execution of the second safety control strategy includes: switching to the first safety control strategy in response to the current value of the motor being greater than the current threshold; and executing the second safety control strategy in response to the current value of the motor being less than or equal to the current threshold.

[0015] According to the safety control method of the motor controller described in one embodiment or any one of the above embodiments of the present application, selectively switching to the first safety control strategy based on the comparison of the current value of the motor and the current threshold during the execution of the second safety control strategy further includes: switching to the first safety control strategy in response to one or more current values ​​of the three-phase current of the motor being greater than the current threshold; and executing the second safety control strategy in response to each current value of the three-phase current of the motor being less than or equal to the current threshold.

[0016] According to the second aspect of the present application, a safety control system for a motor controller is provided, the system comprising: a memory; a processor coupled to the memory; and a computer program stored on the memory and running on the processor, the execution of the computer program resulting in the execution of the steps of the safety control method for the motor controller according to the first aspect of the present application.

[0017] According to a third aspect of the present application, a computer storage medium is provided, wherein the computer storage medium includes instructions, and the instructions, when run, execute the steps of the safety control method for the motor controller according to the first aspect of the present application.

[0018] According to one or more embodiments of the present application, the safety control scheme of the motor controller can selectively execute the first safety control strategy and the second safety control strategy by comparing the back electromotive force value of the motor with the bus voltage value, and selectively switch to the first safety control strategy based on the comparison of the current value of the motor with the current threshold during the execution of the second safety control strategy. It can achieve safe control of the motor within the full speed range, reduce the risk of motor overheating and rotor magnet demagnetization caused by transient current caused by ASC, and improve the safety performance of the motor controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or other aspects and advantages of the present application will become clearer and easier to understand through the following description of various aspects in conjunction with the accompanying drawings, in which the same or similar elements are represented by the same reference numerals. In the drawings:

[0020] FIG1 shows a flow chart of a safety control method for a motor controller according to one or more embodiments of the present application.

[0021] FIG2 shows a flow chart of a safety control method of a motor controller according to one or more embodiments of the present application.

[0022] FIG3 shows a schematic diagram of an inverter of a typical motor controller.

[0023] FIG4 shows a schematic diagram of a variable duty cycle for performing a switching control operation between an active short-circuit operation and a safety pulse shut-off operation according to an embodiment of the present application.

[0024] FIG5 shows a schematic block diagram of a safety control system of a motor controller according to one or more embodiments of the present application. DETAILED DESCRIPTION

[0025] The description of the following specific embodiments is merely exemplary in nature and is not intended to limit the disclosed technology or the application and use of the disclosed technology. In addition, there is no intention to be bound by any express or implied theory presented in the foregoing technical field, background technology or the following specific embodiments.

[0026] In the following detailed description of the embodiments, numerous specific details are set forth to provide a more thorough understanding of the disclosed technology. However, it will be apparent to one of ordinary skill in the art that the disclosed technology can be practiced without these specific details. In other instances, well-known features are not described in detail to avoid unnecessarily complicating the description.

[0027] Terms such as "comprising" and "including" indicate that, in addition to the units and steps directly and explicitly stated in the specification, the technical solution of this application does not exclude the possibility of having other units and steps not directly or explicitly stated. Terms such as "first" and "second" do not indicate the order of units in terms of time, space, size, etc., but are merely used to distinguish between units.

[0028] Hereinafter, various exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings.

[0029] FIG1 shows a flow chart of a safety control method for a motor controller according to one or more embodiments of the present application.

[0030] As shown in FIG. 1 , in step S101 , a back electromotive force value and a bus voltage value of a motor are acquired and the back electromotive force value of the motor is compared with the bus voltage value.

[0031] Optionally, in step S101, the flux and speed of the motor rotor at the current temperature can be obtained, and the back electromotive force value of the motor can be obtained based on the product of the flux of the motor rotor and the speed. For example, the correspondence between the rotor temperature and the flux value can be calibrated experimentally, for example, a steady-state short-circuit test is performed on the motor at different speeds under different rotor temperatures to obtain the relationship between the short-circuit current amplitude, speed and permanent magnet flux value. Optionally, the bus voltage value can be obtained by a bus voltage detection device in a voltage drive system. For example, the bus voltage detection device can be implemented as a voltage transformer installed on the bus. For example, the motor can include a DC motor, an asynchronous motor, a permanent magnet synchronous motor, a switched reluctance motor, etc.

[0032] In one embodiment, before obtaining the back electromotive force value and bus voltage value of the motor, the real-time state of the motor controller is monitored. When the real-time state is determined to be a drive fault state, a drive fault signal is generated based on the drive fault state, and in response to the drive fault signal, the motor controller is triggered to control the motor into a safety protection state. That is, when a vehicle fails and affects driving safety, the safety control method of the motor controller according to one or more embodiments of the present application is executed. For example, vehicle failures may include loss of control of the entire vehicle, power battery failure, abnormal motor speed during vehicle driving, power device failure in the inverter of the motor controller, etc.

[0033] In step S103 , the first safety control strategy is executed in response to the back electromotive force value of the motor being smaller than the bus voltage value.

[0034] Optionally, the first safety control strategy may include an SPO operation, which is used to control each power device in the upper bridge arm and the lower bridge arm of the inverter of the motor controller to be in an off state. It should be noted that in the SPO operation, by controlling each power device in the upper bridge arm and the lower bridge arm of the inverter to be in an off state, the motor is open-circuited, and the motor is stopped by mechanical damping. Exemplarily, the power device may include a power transistor (GTR), a gate turn-off thyristor (GTO), a field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), an integrated gate-commutated thyristor (IGCT), a symmetrical gate-commutated thyristor (SGCT), etc.

[0035] In step S105 , in response to the motor back electromotive force value being greater than or equal to the bus voltage value, the second safety control strategy is executed, wherein during the execution of the second safety control strategy, the first safety control strategy is selectively switched based on the comparison between the motor current value and the current threshold.

[0036] Optionally, the second safety control strategy includes a switching control operation between an ASC operation and an SPO operation. The ASC operation can be used to control the power devices of one of the upper and lower bridge arms in the inverter of the motor controller to be in the on state, and the power devices of the other of the upper and lower bridge arms to be in the off state. During the ASC operation, by controlling the power devices of one of the upper and lower bridge arms in the inverter of the motor controller to be in the on state and the power devices of the other bridge arm to be in the off state, it is possible to ensure that the back electromotive force acts on the three-phase windings inside the motor, thereby achieving separation of the motor and the controller without affecting the safety of energy storage elements such as batteries and capacitors on the DC side.

[0037] Compared with directly executing ASC operation, switching control operation between ASC operation and SPO operation can effectively reduce torque shock and better suppress phase current when the back electromotive force value is greater than or equal to the bus voltage value (i.e., when the vehicle is traveling at high speed).

[0038] In one embodiment, the switching control operation between ASC operation and SPO operation may include controlling the power devices of one of the upper and lower arms of the inverter of the motor controller to remain in an off state, and controlling the power devices of the other of the upper and lower arms of the inverter of the motor controller to be in an on state with a variable duty cycle. It should be noted that the variable duty cycle is used to indicate the proportion of ASC operation in the switching control operation between ASC operation and SPO operation.

[0039] In one embodiment, the power devices in the other of the upper and lower arms of the inverter of the motor controller can be controlled to be in an on-state with a variable duty cycle that gradually increases from a preset initial duty cycle to a maximum duty cycle. When the variable duty cycle increases to the maximum duty cycle, the power devices in the other of the upper and lower arms of the inverter of the motor controller are controlled to remain in an on-state, thereby switching from ASC operation to SPO operation. For example, the preset initial duty cycle can be set within a range of 0%-40%, and the maximum duty cycle can be set to 100%, thereby achieving a smooth transition to ASC operation. For example, the duration of the switching control operation between ASC operation and SPO operation can be set between 10 milliseconds and 20 milliseconds, thereby achieving a smooth transition to ASC operation and ensuring that the vehicle user does not notice it, thereby improving vehicle driving comfort.

[0040] In one embodiment, during the execution of the second safety control strategy, a current sensor can be used to collect the motor's current value in real time and compare it with a current threshold. When the motor's current value exceeds the current threshold, the first safety control strategy can be switched to; when the motor's current value is less than or equal to the current threshold, the second safety control strategy can be continuously executed. In one embodiment, during the execution of the second safety control strategy, each of the collected three-phase currents of the motor can be compared with the current threshold. When one or more current values ​​of the three-phase currents of the motor exceed the current threshold, the first safety control strategy can be switched to; when each current value of the three-phase currents of the motor is less than or equal to the current threshold, the second safety control strategy can be continuously executed. In one embodiment, the current threshold can be set based on the current steady-state current value of the ASC, thereby effectively protecting the motor and preventing erroneous switching of the safety control strategy. For example, when the transient current value of the ASC is 1.1 times the steady-state current value of the ASC, the current threshold can be set to approximately 1.3 times the steady-state current value of the ASC.

[0041] During the execution of the second safety control strategy, the motor current is monitored by comparing the motor current value with the current threshold, which can avoid directly entering the switching control operation between the ASC operation and the SPO operation when the actual back electromotive force is less than the bus voltage (for example, due to the inaccurate back electromotive force value obtained in step S101). At this time, the switching control operation cannot effectively suppress the inrush current on the stator winding, which may cause the motor to overheat, increase the risk of inverter damage and demagnetization of the magnetic steel on the rotor.

[0042] In one or more embodiments of the present application, the switching point of the safety control strategy is determined in real time through the back electromotive force value, the bus voltage value, and the current value of the motor, and the safety state of the motor controller is reasonably controlled and adjusted to minimize the generation of unexpected torque, reduce the risk of motor overheating and rotor magnet demagnetization caused by transient current, ensure the service life of the motor, and improve the safety and controllability of the vehicle.

[0043] According to one aspect of the present application, the safety control method of the motor controller proposed can selectively execute the first safety control strategy and the second safety control strategy by comparing the back electromotive force value of the motor with the bus voltage value, and selectively switch to the first safety control strategy based on the comparison of the current value of the motor with the current threshold during the execution of the second safety control strategy. It can achieve safe control of the motor within the full speed range, reduce the risk of motor overheating and rotor magnet demagnetization caused by transient current caused by ASC, and improve the safety performance of the motor controller.

[0044] FIG2 shows a flow chart of a safety control method of a motor controller according to one or more embodiments of the present application.

[0045] As shown in FIG. 2 , in step S201 , a safety protection state is entered according to motor fault information.

[0046] In step S203, it is determined whether the back electromotive force value of the motor is less than the bus voltage value. If it is determined that the back electromotive force value of the motor is less than the bus voltage value, the process proceeds to step S205; otherwise, the process proceeds to step S207.

[0047] In step S205 , the first security control strategy is executed.

[0048] Optionally, the first safety control strategy may include an SPO operation for controlling each power device in an upper arm and a lower arm of an inverter of the motor controller to be in a disconnected state.

[0049] In step S207, the second safety control strategy is executed. During the execution of the second safety control strategy, it is determined whether the current value of the motor is greater than the current threshold. If the current value of the motor is greater than the current threshold, the process switches to step S205 to execute the first safety control strategy; otherwise, the process proceeds to step S209.

[0050] Optionally, the second safety control strategy includes a switching control operation between an ASC operation and an SPO operation, wherein the ASC operation can be used to control the power devices of one of the upper and lower bridge arms in the inverter of the motor controller to be in an on state, and to control the power devices of the other of the upper and lower bridge arms to be in an off state.

[0051] In step S209 , the second security control strategy is continuously executed to switch to the ASC operation.

[0052] Optionally, the power devices of one of the upper and lower bridge arms in the inverter of the motor controller can be controlled to remain in an off state, and the power devices of the other of the upper and lower bridge arms in the inverter of the motor controller can be controlled to be in an on state with a variable duty cycle. It should be noted that the variable duty cycle is used to indicate the proportion of the ASC operation in the switching control operation between the ASC operation and the SPO operation. In one embodiment, the power devices of the other of the upper and lower bridge arms in the inverter of the motor controller can be controlled to be in an on state with a variable duty cycle that gradually increases from a preset initial duty cycle to a maximum duty cycle, so that when the variable duty cycle increases to the maximum duty cycle, the power devices of the other of the upper and lower bridge arms in the inverter of the motor controller are controlled to remain in an on state, thereby entering the ASC operation from the switching control operation between the ASC operation and the SPO operation.

[0053] FIG3 shows a schematic diagram of an inverter of a typical motor controller.

[0054] As shown in Figure 3, the inverter 300 includes an upper bridge arm and a lower bridge arm, the upper bridge arm includes power devices S1, S3 and S5, and the lower bridge arm includes power devices S2, S4 and S6. The power devices of the upper bridge arm and the lower bridge arm are respectively connected to diodes in reverse parallel. The upper bridge arm of the inverter 300 is connected to the positive pole of the battery B, the lower bridge arm of the inverter 300 is connected to the negative pole of the battery B, and the AC side of the inverter 300 (i.e., the right side in Figure 3) is connected to the motor M. By controlling the on and off of each power device in the upper bridge arm and the lower bridge arm, the direction and magnitude of the current can be controlled, thereby controlling the speed and torque of the motor M. The input end of the inverter 300 is connected in parallel with the bus capacitor C.

[0055] As described above, the SPO operation can be used to control each power device in the upper and lower arms of the inverter of the motor controller to be in the off state. For example, referring to FIG3 , the SPO operation can be used to control the power devices S1, S3, and S5 in the upper arm and the power devices S2, S4, and S6 in the lower arm shown in FIG3 to be in the off state. The ASC operation is used to control the power device in one of the upper and lower arms of the inverter of the motor controller to be in the on state, and to control the power device in the other of the upper and lower arms to be in the off state. For example, referring to Figure 3, the ASC operation can be used to control the power devices S1, S3 and S5 in the upper bridge arm shown in Figure 3 to be in the on state and the power devices S2, S4 and S6 in the lower bridge arm to be in the off state, or the ASC operation can be used to control the power devices S1, S3 and S5 in the upper bridge arm shown in Figure 3 to be in the off state and the power devices S2, S4 and S6 in the lower bridge arm to be in the on state.

[0056] It should be noted that FIG3 is only an exemplary diagram of the topology of the inverter of the motor controller for illustrating SPO and ASC operations. Without departing from the spirit and scope of the present application, the inverter of the motor controller may also be implemented in other topologies.

[0057] FIG4 shows a schematic diagram of a variable duty cycle for performing a switching control operation between an active short-circuit operation and a safety pulse shut-off operation according to an embodiment of the present application.

[0058] As shown in Figure 4, the horizontal axis represents time, and the vertical axis represents the variable duty cycle for performing the switching control operation between the active short-circuit operation and the safety pulse off operation, wherein the period between t1 and t2 shows the time for performing the switching control operation between the active short-circuit operation and the safety pulse off operation, and D1, D2, D3, D4, and D5 respectively represent the variable duty cycles of the switching control operation during multiple sub-periods between t1 and t2.

[0059] During the period from t1 to t2, the power devices of one of the upper and lower bridge arms in the inverter of the motor controller can be controlled to remain in the disconnected state, and the power devices of the other of the upper and lower bridge arms in the inverter of the motor controller can be controlled to be in the on state with variable duty cycles D1, D2, D3, D4, and D5.

[0060] For example, the variable duty cycles D1, D2, D3, D4, and D5 can be set to initial duty cycles of 20%, 40%, 60%, and 80%, respectively, and to a maximum duty cycle of 100%. After t2, the system fully switches to ASC operation. For example, the period between t1 and t2 can be set between 10 milliseconds and 20 milliseconds to achieve a smooth transition to ASC operation without noticeable to the vehicle user, thereby enhancing driving comfort. For example, the preset initial duty cycle D1 can be set within a range of 0%-40%.

[0061] FIG5 shows a schematic block diagram of a safety control system of a motor controller according to one or more embodiments of the present application.

[0062] 5 , a motor controller safety control system 500 includes a memory 510, a processor 520, and a computer program 530 stored in the memory 510 and executable on the processor 520. The processor 520 executes the computer program 530 to implement a motor controller safety control method according to one aspect of the present application.

[0063] In addition, the present application may also be implemented as a computer storage medium in which a program for causing a computer to execute the safety control method for a motor controller according to one aspect of the present application is stored.

[0064] Here, as computer storage media, various types of computer storage media can be used, such as disks (for example, magnetic disks, optical disks, etc.), cards (for example, memory cards, optical cards, etc.), semiconductor memories (for example, ROMs, non-volatile memories, etc.), and tapes (for example, magnetic tapes, cassette tapes, etc.).

[0065] In the applicable situation, the combination of hardware, software or hardware and software can be used to realize the various embodiments provided by the application. Moreover, in the applicable situation, without departing from the scope of the application, the various hardware components and / or software components set forth herein can be combined into a composite component comprising software, hardware and / or both. In the applicable situation, without departing from the scope of the application, the various hardware components and / or software components set forth herein can be divided into a subcomponent comprising software, hardware or both. In addition, in the applicable situation, it is contemplated that the software component can be implemented as a hardware component, and vice versa.

[0066] Software according to the present application (such as program code and / or data) can be stored on one or more computer storage media. It is also contemplated that the software identified herein can be implemented using one or more general or special computers and / or computer systems, networked and / or otherwise. Where applicable, the order of the various steps described herein can be changed, combined into composite steps and / or divided into sub-steps to provide the features described herein.

[0067] The embodiments and examples set forth herein are provided to best illustrate embodiments according to the present application and its specific applications, and thereby enable those skilled in the art to make and use the present application. However, those skilled in the art will appreciate that the above description and examples are provided for ease of illustration and example only. The descriptions set forth are not intended to be exhaustive of all aspects of the present application or to limit the present application to the precise forms disclosed.

Claims

1. A safety control method for a motor controller, characterized in that: The method comprises the following steps: Acquire a back electromotive force value and a bus voltage value of the motor and compare the back electromotive force value of the motor with the bus voltage value; executing a first safety control strategy in response to a back electromotive force value of the motor being less than a bus voltage value; as well as executing a second safety control strategy in response to a back electromotive force value of the motor being greater than or equal to the bus voltage value; During the execution of the second safety control strategy, the first safety control strategy is selectively switched based on a comparison between the current value of the motor and a current threshold.

2. The method according to claim 1, wherein obtaining the back electromotive force value of the motor comprises: Get the magnetic flux and speed of the motor rotor at the current temperature; as well as The back electromotive force value of the motor is obtained based on the product of the magnetic flux and the rotation speed of the motor rotor. 3 . The method according to claim 1 , wherein the first safety control strategy comprises a safety pulse off operation, and the second safety control strategy comprises a switching control operation between an active short circuit operation and a safety pulse off operation.

4. The method of claim 3, wherein the safety pulse off operation comprises: Each power device in the upper bridge arm and the lower bridge arm in the inverter of the motor controller is controlled to be in a disconnected state.

5. The method according to claim 3, wherein the active short circuit operation comprises: A power device of one of an upper bridge arm and a lower bridge arm in an inverter of a motor controller is controlled to be in an on state, and a power device of the other of the upper bridge arm and the lower bridge arm is controlled to be in an off state.

6. The method according to claim 3, wherein the switching control operation between the active short circuit operation and the safety pulse off operation comprises: Controlling a power device in one of an upper bridge arm and a lower bridge arm in an inverter of a motor controller to remain in an off state; as well as A power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller is controlled to be in a conducting state at a variable duty cycle.

7. The method according to claim 6, wherein controlling the power device of the other of the upper bridge arm and the lower bridge arm in the inverter of the motor controller to be in a conducting state with a variable duty cycle comprises: The power device of the other one of the upper bridge arm and the lower bridge arm in the inverter of the motor controller is controlled to be in the on state with a variable duty cycle that gradually increases from a preset initial duty cycle to a maximum duty cycle, so that when the variable duty cycle increases to the maximum duty cycle, the power device of the other one of the upper bridge arm and the lower bridge arm in the inverter of the motor controller is controlled to remain in the on state.

8. The method of claim 1, wherein selectively switching to the first safety control strategy based on a comparison of the current value of the motor with a current threshold during execution of the second safety control strategy comprises: In response to the current value of the motor being greater than the current threshold, switching to the first safety control strategy; as well as The second safety control strategy is executed in response to the current value of the motor being less than or equal to the current threshold.

9. The method of claim 8, wherein selectively switching to the first safety control strategy based on a comparison of the current value of the motor with a current threshold during execution of the second safety control strategy further comprises: switching to the first safety control strategy in response to one or more current values ​​of the three-phase currents of the motor being greater than the current threshold; as well as In response to each current value of the three-phase current of the motor being less than or equal to the current threshold, executing The second security control strategy.

10. A safety control system for a motor controller, characterized in that: The system comprises: Memory; a processor coupled to the memory; and A computer program stored on the memory and running on the processor, wherein the running of the computer program results in the execution of the safety control method of the motor controller according to any one of claims 1 to 9.

11. A computer storage medium, characterized in that: The computer storage medium includes instructions, which, when executed, execute the safety control method for the motor controller according to any one of claims 1 to 9.

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