Motor safety state control circuit, system and method and driving equipment

Abstract

The invention relates to the technical field of motor control, particularly provides a motor safety state control circuit, system and method and driving equipment, and aims to solve the problem that a proper safety state cannot be selected to control a motor according to actual working conditions when a power supply fault or a vehicle driving system fault occurs in the prior art. In order to achieve the purpose, the motor safety state control circuit is applied to a vehicle driving system, the vehicle driving system comprises an MCU and a motor, and the safety state control circuit comprises a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor rotating speed signal or a vehicle speed signal and output a corresponding speed state signal; and the safety state switching circuit is configured to control the safety state of the motor to be an active short-circuit state or a safety turn-off state or to be switched between the active short-circuit state and the safety turn-off state based on the speed state signal and the MCU state signal.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a motor safety state control circuit, system, method and driving device. Background Art

[0002] New energy vehicles rely on the motor drive system to provide power to drive the vehicle. The low-voltage part of the electric drive system is powered by a low-voltage battery, and the high-voltage DC power of the power battery is converted into three-phase AC power to drive the motor to drive the vehicle, or the three-phase AC current at the motor end is converted into high-voltage DC power to feed back to the battery for charging, thereby realizing the four-quadrant control of the motor. When other serious fault conditions such as battery KL30 power failure or damage to the microprocessor chip (MCU) of the electric drive system occur, the vehicle needs to be able to automatically enter a safe state to prevent the vehicle from generating unexpected torque. In general, the electric drive system will directly enter the active short circuit (ASC) state to prevent direct locking at high speed, or enter the safe shutdown (SPO) state.

[0003] However, both the active short circuit (ASC) state and the safe shutdown (SPO) state have their disadvantages under certain working conditions. For example, when the vehicle is in a low-speed driving state, entering the active short circuit (ASC) state will have a large negative torque, affecting the driving experience and safety; when the vehicle is in a high-speed driving state, entering the safe shutdown (SPO) state will cause the electric drive system to have uncontrolled rectification, eventually damaging the electric drive system.

[0004] Accordingly, the art needs a new motor safety state control solution to solve the above problems. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the technical problem that when a power failure or a vehicle drive system failure occurs, a suitable safe state cannot be selected according to the actual working conditions to control the motor.

[0006] In a first aspect, a motor safety state control circuit is provided, which is applied to a vehicle drive system, wherein the vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal, and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state based on the speed state signal and the MCU state signal.

[0007] In a technical solution of the above-mentioned motor safety state control circuit, the safety state control circuit also includes an OR gate logic circuit, which is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, so that the safety state switching circuit outputs a corresponding control signal based on the input signal to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

[0008] In a technical solution of the above-mentioned motor safety state control circuit, the OR gate logic circuit is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, including: when the MCU state signal is at a high level, the high level indicates that the MCU is in a normal working state and the MCU is powered normally, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the MCU state signal, and the safety state switching circuit outputs a corresponding control signal based on the MCU state signal; when the MCU state signal is at a low level, the low level indicates that the MCU fails or the MCU power is off, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed state signal, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal.

[0009] In a technical solution of the above-mentioned motor safety state control circuit, the speed state signal includes a first speed state signal or a second speed state signal, and the speed judgment circuit includes a comparator, which is configured to obtain the motor speed signal or the vehicle speed signal, and judge whether the motor speed signal or the vehicle speed signal is greater than or equal to a corresponding preset threshold value, and output a first speed state signal when the motor speed signal or the vehicle speed signal is greater than or equal to the corresponding preset threshold value; or, output a second speed state signal when the motor speed signal or the vehicle speed signal is less than the corresponding preset threshold value.

[0010] In a technical solution of the above-mentioned motor safety state control circuit, the vehicle drive system also includes an inverter and a drive circuit, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal, including: when the speed state signal is a first speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a first control signal to the inverter, so that the inverter controls the motor to enter an active short-circuit state based on the first control signal; or, when the speed state signal is a second speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal; the first disabled state is to prohibit the drive circuit from controlling the inverter to drive the motor to work.

[0011] In a technical solution of the above-mentioned motor safety state control circuit, the safety state switching circuit is also configured to continuously obtain a new speed state signal after controlling the motor to enter an active short-circuit state, and when the new speed state signal is a second speed state signal, output a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal.

[0012] In a technical solution of the above-mentioned motor safety state control circuit, the speed judgment circuit also includes a speed signal processing module, which is configured to obtain a motor speed signal or a vehicle speed signal, process the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal, and output the voltage signal to the comparator, so that the comparator outputs the speed state signal based on the voltage signal.

[0013] In a technical solution of the above-mentioned motor safety state control circuit, the safety state control circuit also includes a first power supply module, and the first power supply module is configured to supply power to the speed signal processing module and the safety state switching circuit.

[0014] In a second aspect, a motor safety state control system is provided, the system comprising a motor safety state control circuit and a vehicle drive system as described in any of the above technical solutions; the vehicle drive system comprises an MCU, an MCU power module, an inverter and a motor, the motor safety state control circuit and the MCU are connected in parallel to jointly control the inverter, and control the motor via the inverter; wherein, when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the motor to operate via the inverter; when the MCU is in abnormal working state or the MCU power module is powered abnormally, the motor safety state control circuit controls the inverter based on the speed state signal, and controls the motor via the inverter to be in an active short circuit state, or a safe shutdown state, or to switch between an active short circuit state and a safe shutdown state.

[0015] In a technical solution of the above-mentioned motor safety state control system, the vehicle drive system also includes a drive circuit, and the drive circuit is configured such that when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the inverter through the drive circuit to drive the motor to work, and generates an MCU status signal, and sends the MCU status signal to the safety state control circuit, so that the safety state control circuit enters a second disabled state based on the MCU status signal, and the MCU status signal is a high level, and the second disabled state prohibits the safety state switching circuit from obtaining the speed status signal.

[0016] In a technical solution of the above-mentioned motor safety state control system, the MCU is configured to obtain a motor speed signal or a vehicle speed signal when the MCU is in normal working state and the MCU power module is powered normally, and generate an active short-circuit control signal or a safe shutdown control signal based on the motor speed signal or the vehicle speed signal, and send the active short-circuit control signal or the safe shutdown control signal to the safe state switching circuit, so that the safe state switching circuit controls the inverter based on the active short-circuit control signal or the safe shutdown control signal, and controls the motor to enter an active short-circuit state or a safe shutdown state via the inverter.

[0017] In a technical solution of the above-mentioned motor safety state control system, the MCU is configured to generate an MCU status signal when the MCU working state is abnormal or the power supply of the MCU power module is abnormal, and send the MCU status signal to the OR gate logic circuit of the safety state control circuit, so that the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed status signal based on the MCU status signal and the speed status signal, and the MCU status signal is a low level.

[0018] In a third aspect, a driving device is provided, comprising a motor safety state control circuit or a motor safety state control system as described in any of the above technical solutions.

[0019] In a fourth aspect, a motor safety state control method is provided, the method is performed based on the motor safety state control circuit or the motor safety state control system as described in any of the above technical solutions, the method comprising: obtaining a motor speed signal or a vehicle speed signal, and an MCU status signal; determining a speed status signal based on the motor speed signal or the vehicle speed signal; a safety state switching circuit generates a first control signal or a second control signal based on the speed status signal and the MCU status signal, and controls an inverter based on the first control signal or the second control signal, and controls the motor via the inverter to enter an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

[0020] In a technical solution of the above-mentioned motor safety state control method, the speed state signal includes a first speed state signal or a second speed state signal; the speed state signal is determined based on the motor speed signal or the vehicle speed signal, including: a speed signal processing module processes the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal; a comparator determines whether the voltage signal is greater than or equal to a preset threshold, and when the voltage signal is greater than or equal to the preset threshold, outputs the first speed state signal to the safety state switching circuit; or, when the voltage signal is less than the preset threshold, outputs the second speed state signal to the safety state switching circuit.

[0021] In a technical solution of the above-mentioned motor safety state control method, the safety state switching circuit generates a first control signal or a second control signal based on the speed state signal and the MCU state signal, and controls the inverter based on the first control signal or the second control signal, and controls the motor to enter an active short-circuit state or a safe shutdown state through the inverter, or switches between the active short-circuit state and the safe shutdown state, including: when the MCU state signal is at a low level, the safety state switching circuit determines a first control signal based on the MCU state signal and the first speed state signal, and controls the inverter based on the first control signal, and controls the motor to enter an active short-circuit state through the inverter; or, when the MCU state signal is at a low level, the safety state switching circuit determines a second control signal based on the MCU state signal and the second speed state signal, and controls the inverter based on the second control signal, and controls the motor to enter a safe shutdown state through the inverter.

[0022] In a technical solution of the above-mentioned motor safety state control method, after controlling the motor to enter an active short-circuit state, the method also includes: the safety state switching circuit continuously acquires a new speed state signal; the safety state switching circuit determines a second control signal when the new speed state signal is a second speed state signal, and controls the inverter based on the second control signal, and controls the motor to enter a safe shutdown state via the inverter.

[0023] In a technical solution of the above-mentioned motor safety state control method, the method also includes: when the MCU state signal is at a high level, the MCU determines an active short-circuit control signal or a safety shutdown control signal based on the motor speed signal or the vehicle speed signal, and sends the active short-circuit control signal or the safety shutdown control signal to a safety state switching circuit; the safety state switching circuit controls the inverter based on the active short-circuit control signal or the safety shutdown control signal, and controls the motor to enter an active short-circuit state or a safety shutdown state via the inverter.

[0024] Solution 1. A motor safety state control circuit, applied to a vehicle drive system, characterized in that the vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal, and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between an active short circuit state and a safe shutdown state based on the speed state signal and the MCU state signal.

[0025] Solution 2. The motor safety state control circuit according to Solution 1 is characterized in that the safety state control circuit also includes an OR gate logic circuit, and the OR gate logic circuit is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, so that the safety state switching circuit outputs a corresponding control signal based on the input signal to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

[0026] Solution 3. The motor safety state control circuit according to Solution 2 is characterized in that the OR gate logic circuit is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, including:

[0027] When the MCU status signal is at a high level, the high level indicates that the MCU is in a normal working state and the MCU is powered normally, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the MCU status signal, and the safety state switching circuit outputs a corresponding control signal based on the MCU status signal;

[0028] When the MCU status signal is at a low level, the low level indicates that the MCU is faulty or the MCU power is off, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed state signal, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal.

[0029] Scheme 4. The motor safety state control circuit according to Scheme 3 is characterized in that the speed state signal includes a first speed state signal or a second speed state signal, and the speed judgment circuit includes a comparator, and the comparator is configured to obtain the motor speed signal or the vehicle speed signal, and judge whether the motor speed signal or the vehicle speed signal is greater than or equal to a corresponding preset threshold value, and output a first speed state signal when the motor speed signal or the vehicle speed signal is greater than or equal to the corresponding preset threshold value; or output a second speed state signal when the motor speed signal or the vehicle speed signal is less than the corresponding preset threshold value.

[0030] Solution 5. The motor safety state control circuit according to Solution 4 is characterized in that the vehicle drive system further includes an inverter and a drive circuit, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal, including:

[0031] When the speed state signal is a first speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a first control signal to the inverter, so that the inverter controls the motor to enter an active short-circuit state based on the first control signal; or,

[0032] When the speed state signal is a second speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal; the first disabled state prohibits the drive circuit from controlling the inverter to drive the motor to work.

[0033] Solution 6. The motor safety state control circuit according to Solution 5 is characterized in that the safety state switching circuit is also configured to continuously obtain a new speed state signal after controlling the motor to enter an active short-circuit state, and when the new speed state signal is a second speed state signal, output a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal.

[0034] Solution 7. The motor safety state control circuit according to Solution 4 is characterized in that the speed judgment circuit also includes a speed signal processing module, and the speed signal processing module is configured to obtain a motor speed signal or a vehicle speed signal, process the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal, and output the voltage signal to the comparator, so that the comparator outputs the speed state signal based on the voltage signal.

[0035] Solution 8. The motor safety state control circuit according to Solution 7 is characterized in that the safety state control circuit also includes a first power supply module, and the first power supply module is configured to supply power to the speed signal processing module and the safety state switching circuit.

[0036] Solution 9. A motor safety state control system, characterized in that the system comprises a motor safety state control circuit and a vehicle drive system as described in any one of Solutions 1 to 8;

[0037] The vehicle drive system includes an MCU, an MCU power module, an inverter and a motor. The motor safety state control circuit and the MCU are connected in parallel to jointly control the inverter, and the motor is controlled via the inverter; wherein, when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the motor to operate via the inverter; when the MCU is in abnormal working state or the MCU power module is powered abnormally, the motor safety state control circuit controls the inverter based on the speed state signal, and controls the motor to be in an active short circuit state, or a safe shutdown state, or switches between the active short circuit state and the safe shutdown state via the inverter.

[0038] Solution 10. According to the motor safety state control system of Solution 9, it is characterized in that the vehicle drive system also includes a drive circuit, and the drive circuit is configured so that when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the inverter through the drive circuit to drive the motor to work, and generates an MCU state signal, and sends the MCU state signal to the safety state control circuit, so that the safety state control circuit enters a second disabled state based on the MCU state signal, and the MCU state signal is at a high level. The second disabled state prohibits the safety state switching circuit from obtaining the speed state signal.

[0039] Solution 11. According to the motor safety state control system of Solution 9, it is characterized in that the MCU is configured to obtain a motor speed signal or a vehicle speed signal when the MCU is in normal working state and the MCU power module is powered normally, and generate an active short-circuit control signal or a safe shutdown control signal based on the motor speed signal or the vehicle speed signal, and send the active short-circuit control signal or the safe shutdown control signal to the safe state switching circuit, so that the safe state switching circuit controls the inverter based on the active short-circuit control signal or the safe shutdown control signal, and controls the motor to enter an active short-circuit state or a safe shutdown state via the inverter.

[0040] Solution 12. The motor safety state control system according to Solution 9 is characterized in that the MCU is configured to generate an MCU status signal when the MCU working state is abnormal or the power supply of the MCU power module is abnormal, and send the MCU status signal to the OR gate logic circuit of the safety state control circuit, so that the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed status signal based on the MCU status signal and the speed status signal, and the MCU status signal is a low level.

[0041] Solution 13. A driving device, characterized in that it includes a motor safety state control circuit as described in any one of Solutions 1-8 or a motor safety state control system as described in any one of Solutions 9 to 12.

[0042] Solution 14. A motor safety state control method, the method is executed based on the motor safety state circuit described in any one of Solutions 1-8 or the motor safety state control system described in any one of Solutions 9 to 12, characterized in that the method comprises:

[0043] Obtain motor speed signal or vehicle speed signal and MCU status signal;

[0044] Determining a speed state signal based on the motor speed signal or the vehicle speed signal;

[0045] The safety state switching circuit generates a first control signal or a second control signal based on the speed state signal and the MCU state signal, and controls the inverter based on the first control signal or the second control signal, and controls the motor through the inverter to enter an active short-circuit state, or a safe shutdown state, or switches between the active short-circuit state and the safe shutdown state.

[0046] Solution 15. The motor safety state control method according to Solution 14 is characterized in that the speed state signal includes a first speed state signal or a second speed state signal; and determining the speed state signal based on the motor speed signal or the vehicle speed signal includes:

[0047] The speed signal processing module processes the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal;

[0048] The comparator determines whether the voltage signal is greater than or equal to a preset threshold value, and outputs a first speed state signal to the safety state switching circuit when the voltage signal is greater than or equal to the preset threshold value; or,

[0049] When the voltage signal is less than a preset threshold, a second speed state signal is output to the safety state switching circuit.

[0050] Solution 16. The motor safety state control method according to Solution 15 is characterized in that the safety state switching circuit generates a first control signal or a second control signal based on the speed state signal and the MCU state signal, and controls the inverter based on the first control signal or the second control signal, and controls the motor to enter an active short circuit state, or a safe shutdown state, or switches between the active short circuit state and the safe shutdown state via the inverter, including:

[0051] When the MCU state signal is at a low level, the safety state switching circuit determines a first control signal based on the MCU state signal and the first speed state signal, controls the inverter based on the first control signal, and controls the motor to enter an active short-circuit state via the inverter; or,

[0052] When the MCU state signal is at a low level, the safety state switching circuit determines a second control signal based on the MCU state signal and the second speed state signal, controls the inverter based on the second control signal, and controls the motor to enter a safety shutdown state via the inverter.

[0053] Solution 17. The motor safety state control method according to Solution 16 is characterized in that after controlling the motor to enter the active short-circuit state, the method further includes:

[0054] The safety state switching circuit continuously acquires a new speed state signal;

[0055] When the new speed state signal is the second speed state signal, the safety state switching circuit determines a second control signal, controls the inverter based on the second control signal, and controls the motor to enter a safety shutdown state via the inverter.

[0056] Solution 18. The motor safety state control method according to Solution 15 is characterized in that the method further comprises:

[0057] When the MCU state signal is at a high level, the MCU determines an active short circuit control signal or a safety shutdown control signal based on the motor speed signal or the vehicle speed signal, and sends the active short circuit control signal or the safety shutdown control signal to a safety state switching circuit;

[0058] The safety state switching circuit controls an inverter based on the active short circuit control signal or the safety shutdown control signal, and controls the motor to enter an active short circuit state or a safety shutdown state via the inverter.

[0059] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0060] The present application provides a motor safety state control circuit, which is applied to a vehicle drive system, wherein the vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal, and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or switch between an active short circuit state and a safe shutdown state based on the speed state signal and the MCU state signal. The motor safety state control circuit of the present application can determine the operating state of the motor according to the motor speed signal or the vehicle speed signal, and then can switch the motor to a safe state suitable for the current working conditions based on the operating state of the motor and the operating state of the MCU, thereby effectively improving the overall safety of the motor system, and avoiding the problem of reduced user experience or damage to electric drive system components due to the motor executing an erroneous safety state. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0062] Figure 1 It is a main structural diagram of a motor safety state control circuit according to an embodiment of the present application.

[0063] Figure 2 It is a main structural diagram of a driving device according to an embodiment of the present application.

[0064] Figure 3 It is a flowchart of the main steps of a motor safety state control method according to an embodiment of the present application.

[0065] Figure 4 It is a detailed step flow chart of a motor safety state control method according to an embodiment of the present application. DETAILED DESCRIPTION

[0066] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0067] In the description of the present application, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, memory, and may also include software parts, such as program code, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware or a combination of the two. Computer-readable storage media include any suitable medium that can store program code, such as a disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B" and may include only A, only B or A and B. The singular terms "one" and "the" may also include plural forms.

[0068] When new energy vehicles encounter other serious fault conditions such as battery KL30 power failure or electric drive system microprocessor chip (MCU) damage, the vehicle needs to be able to automatically enter a safe state to prevent the vehicle from generating unexpected torque. Under normal circumstances, the electric drive system will directly enter the active short circuit (ASC) state, or enter the safe shutdown (SPO) state. However, whether it enters the active short circuit (ASC) state or the safe shutdown (SPO) state, it has its disadvantages under specific conditions. For example, when the vehicle is in a low-speed driving state, entering the active short circuit (ASC) state will have a large negative torque, affecting the driving experience and safety; when the vehicle is in a high-speed driving state, entering the safe shutdown (SPO) state will cause the electric drive system to uncontrolled rectification, and eventually damage the electric drive system.

[0069] To this end, the present application provides a motor safety state control circuit, which is applied to a vehicle drive system, wherein the vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal, and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or switch between an active short circuit state and a safe shutdown state based on the speed state signal and the MCU state signal. The motor safety state control circuit of the present application can determine the operating state of the motor according to the motor speed signal or the vehicle speed signal, and then can switch the motor to a safe state suitable for the current working conditions based on the operating state of the motor and the operating state of the MCU, thereby effectively improving the overall safety of the motor system, and avoiding the problem of reduced user experience or damage to electric drive system components caused by the motor executing an erroneous safety state.

[0070] See attached Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the main structure of a motor safety state control circuit according to an embodiment of the present application. Figure 1 As shown, in one embodiment of the present application, a motor safety state control circuit is applied to a vehicle drive system, the vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal, and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between an active short circuit state and a safe shutdown state based on the speed state signal and the MCU state signal.

[0071] Specifically, the speed judgment circuit determines the speed status signal by obtaining any one of the motor speed signal or the vehicle speed signal; the safety state switching circuit determines whether the MCU fails according to the MCU status signal. The cause of the MCU failure may be the MCU power supply failure or the MCU local operation failure. The MCU is powered by a battery, and the MCU power supply failure refers to the battery KL30 power supply failure; when the safety state switching circuit determines that the MCU has failed, it determines which safety state to select to control the motor under the current working conditions according to the speed status signal.

[0072] The motor safety state control circuit of the present application can determine the operating state of the motor according to the motor speed signal or the vehicle speed signal, and then can switch the motor to a safe state suitable for the current operating conditions based on the operating state of the motor and the operating state of the MCU, thereby effectively improving the overall safety of the motor system and avoiding the problem of reduced user experience or damage to electric drive system components due to the motor executing an erroneous safety state.

[0073] In one embodiment, the speed judgment circuit also includes a speed signal processing module, which is configured to obtain a motor speed signal or a vehicle speed signal, process the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal, and output the voltage signal to the comparator, so that the comparator outputs the speed status signal based on the voltage signal.

[0074] Specifically, the signal processing module obtains the motor speed signal or the vehicle speed signal. The signal processing method is selected according to the signal type to process the acquired signal to obtain a voltage signal representing the current speed or vehicle speed. The signal processing method includes low-pass filtering or frequency-voltage conversion, which is not specifically limited here.

[0075] In one embodiment, the speed status signal includes a first speed status signal or a second speed status signal, and the speed judgment circuit includes a comparator, which is configured to obtain the motor speed signal or the vehicle speed signal, and determine whether the motor speed signal or the vehicle speed signal is greater than or equal to a corresponding preset threshold value, and output a first speed status signal when the motor speed signal or the vehicle speed signal is greater than or equal to the corresponding preset threshold value; or output a second speed status signal when the motor speed signal or the vehicle speed signal is less than the corresponding preset threshold value.

[0076] Specifically, the speed judgment circuit also includes a comparator. The comparator obtains the voltage signal of the signal processing module and determines whether the voltage signal is greater than or equal to a preset threshold. When the voltage signal is greater than or equal to the preset threshold, it is considered that the current motor speed or vehicle speed is high. Under this condition, if the motor is controlled to enter a safe shutdown state, the electric drive system may "uncontrolled rectification" (i.e., the power electronic converter loses control), which may cause parameters such as current and voltage to exceed the safety range, thereby damaging the components of the electric drive system. Therefore, the first speed state signal is output, and the first speed state signal is a high level.

[0077] When the voltage signal is less than the preset threshold, it is considered that the current motor speed or vehicle speed is low. Under this condition, if the motor is controlled to enter the active shutdown state, a large negative torque may be generated. The large negative torque may cause passengers to feel a significant deceleration, or in extreme cases, affect the vehicle's handling performance. Therefore, the second speed state signal is output, and the second speed state signal is a low level.

[0078] In one embodiment, the safety state control circuit also includes an OR gate logic circuit, which is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, so that the safety state switching circuit outputs a corresponding control signal based on the input signal to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

[0079] Specifically, the OR gate logic circuit is composed of two diodes, the input end of one diode is connected to the output end of the comparator, and the input end of the other diode is connected to the output end of the MCU. The OR gate logic circuit determines the input signal of the safety state switching circuit by obtaining the MCU state signal and the speed state signal output by the comparator, and then the safety state switching circuit controls the motor to enter the active short circuit state, the safe shutdown state, or switch between the active short circuit state and the safe shutdown state according to the input signal. The active short circuit state refers to the ASC state (Active Short Circuit), and the safe shutdown state refers to the SPO (Safety Pulse Off) state.

[0080] In one embodiment, the OR gate logic circuit is configured to determine the input signal of the safety state switching circuit based on the MCU status signal and the speed status signal output by the speed judgment circuit, including: when the MCU status signal is at a high level, the high level indicates that the MCU is in a normal working state and the MCU is powered normally, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the MCU status signal, and the safety state switching circuit outputs a corresponding control signal based on the MCU status signal; when the MCU status signal is at a low level, the low level indicates that the MCU is faulty or the MCU power is off, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed status signal, and the safety state switching circuit outputs a corresponding control signal based on the speed status signal.

[0081] Specifically, when the MCU does not fail, the MCU state signal is at a high level. At this time, the OR gate logic circuit does not receive the speed state signal output by the speed judgment circuit. The input signal of the safety state switching circuit determined by the OR gate logic circuit is the MCU state signal, that is, a high level. When the MCU state signal is at a high level, the safety state switching circuit outputs a corresponding control signal based on the active control signal or the safety shutdown signal output by the MCU to control the motor to enter a safe state; if the MCU does not output an active short-circuit signal or a safety shutdown signal, the motor maintains normal operation. In other words, when the MCU does not fail and the vehicle drive system operates normally, the MCU determines whether to control the motor to enter a safe state based on the vehicle speed or the motor speed.

[0082] In the case of a MCU failure, the MCU state signal is at a low level, and the OR gate logic circuit receives the speed state signal output by the comparator. Because the MCU state signal is at a low level, the input signal of the safety state switching circuit determined by the OR gate logic circuit is determined by the speed state signal. The safety state switching circuit outputs a corresponding control signal based on the input signal, and the control signal controls the motor to enter an active short circuit state or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

[0083] In one embodiment, the vehicle drive system also includes an inverter and a drive circuit, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal, including: when the speed state signal is a first speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a first control signal to the inverter, so that the inverter controls the motor to enter an active short-circuit state based on the first control signal; or, when the speed state signal is a second speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal; the first disabled state is to prohibit the drive circuit from controlling the inverter to drive the motor to work.

[0084] Specifically, when the speed state signal is the first speed state signal (high level), the MCU state signal is low level, and the OR gate logic circuit determines that the input signal of the safety state switching circuit is high level, when the input signal is high level, the safety state switching circuit controls the drive circuit to enter the first disabled state, that is, prohibits the drive circuit from controlling the inverter to drive the motor to work, and outputs the first control signal to the inverter. The first control signal controls the inverter and the motor to enter an active short circuit state.

[0085] When the speed state signal is the second speed state signal (low level), the MCU state signal is low level, and the OR gate logic circuit determines that the input signal of the safety state switching circuit is low level, when the input signal is low level, the safety state switching circuit controls the drive circuit to enter the first disabled state, that is, prohibits the drive circuit from controlling the inverter to drive the motor to work, and outputs a second control signal to the inverter, and the second control signal controls the inverter and the motor to enter a safe shutdown state.

[0086] In one embodiment, the safety state switching circuit is also configured to continuously obtain a new speed state signal after controlling the motor to enter an active short-circuit state, and when the new speed state signal is a second speed state signal, output a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal.

[0087] Specifically, after the motor is controlled to enter the active short-circuit state, the signal processing module continuously monitors the motor speed signal or the vehicle speed signal, and the safety state switching circuit continuously obtains the speed state signal generated by the OR gate logic circuit according to the new motor speed signal or the vehicle speed signal. When the speed state signal changes to the second speed state signal, it indicates that the vehicle speed and the motor speed have decreased at this time, and the safety state switching circuit outputs the second control signal to the inverter, and the inverter controls the motor to change from the active short-circuit state to the safe shutdown state based on the second control signal. This is to avoid the problem that the motor remains in the active shutdown state under the condition of low motor speed and vehicle speed, resulting in a large negative torque, thereby affecting the user's driving experience, or in extreme cases, affecting the vehicle's handling performance.

[0088] In one embodiment, the safety state control circuit further includes a first power supply module, and the first power supply module is configured to supply power to the speed signal processing module and the safety state switching circuit.

[0089] Specifically, the safety state control circuit includes a first power supply module, which can independently power the speed signal processing module and the safety state switching circuit. The power supply of the first power supply module comes from the power battery, and the power supply of the first power supply module is not affected by whether the battery KL30 is powered off or whether the MCU is faulty.

[0090] Another aspect of the present application also provides a motor safety state control system.

[0091] In one embodiment of the present application, a motor safety state control system includes a motor safety state control circuit and a vehicle drive system as described in any of the above embodiments; the vehicle drive system includes an MCU, an MCU power module, an inverter and a motor, the motor safety state control circuit and the MCU are connected in parallel to jointly control the inverter, and control the motor via the inverter; wherein, when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the motor to operate via the inverter; when the MCU is in abnormal working state or the MCU power module is powered abnormally, the motor safety state control circuit controls the inverter based on the speed state signal, and controls the motor to be in an active short circuit state, or a safe shutdown state, or switches between an active short circuit state and a safe shutdown state via the inverter.

[0092] Specifically, the motor safety state control circuit and the control path of the MCU are connected in parallel to jointly control the inverter, and control the motor via the inverter.

[0093] When the MCU is in normal working state and the power supply of the MCU power module is normal, the battery KL30 supplies power to the MCU through the MCU power module, and the MCU controls the inverter drive motor to work normally through the drive circuit.

[0094] When the MCU working state is abnormal or the power supply of the MCU power module is abnormal, the motor safety state switching circuit directly controls the inverter based on the current speed state signal, and controls the motor through the inverter to be in an active short-circuit state, or a safe shutdown state, or switches between the active short-circuit state and the safe shutdown state.

[0095] In one embodiment, the vehicle drive system also includes a drive circuit, which is configured to control the inverter to drive the motor to work through the drive circuit when the MCU is in normal working state and the MCU power module is powered normally, and generate an MCU status signal, and send the MCU status signal to the safety state control circuit, so that the safety state control circuit enters a second disabled state based on the MCU status signal, and the MCU status signal is a high level. The second disabled state prohibits the safety state switching circuit from obtaining the speed status signal.

[0096] Specifically, the vehicle drive system also includes a drive circuit. When the MCU is in normal working state and the MCU power module is supplying power normally, the MCU controls the inverter to drive the motor via the drive circuit. At the same time, the MCU generates an MCU status signal (the MCU status signal is a high level) and sends it to the safety state switching circuit to notify the safety state switching circuit that the working state of the vehicle drive system is normal. The safety state switching circuit enters a second disabled state according to the MCU status signal (high level). The second disabled state is that the safety state switching circuit stops receiving the speed status signal output by the OR gate logic circuit.

[0097] In one embodiment, the MCU is configured to obtain a motor speed signal or a vehicle speed signal when the MCU is in normal working state and the MCU power module is powered normally, and generate an active short-circuit control signal or a safe shutdown control signal based on the motor speed signal or the vehicle speed signal, and send the active short-circuit control signal or the safe shutdown control signal to the safe state switching circuit, so that the safe state switching circuit controls the inverter based on the active short-circuit control signal or the safe shutdown control signal, and controls the motor to enter an active short-circuit state or a safe shutdown state via the inverter.

[0098] Specifically, when the MCU is in normal working state and the MCU power module is supplying power normally, during the normal operation of the vehicle drive system, the MCU obtains the motor speed signal or the vehicle speed signal, and generates an active short-circuit control signal or a safe shutdown control signal based on the motor speed signal or the vehicle speed signal, and then sends the generated active short-circuit control signal or the safe shutdown control signal to the safe state switching circuit, and the safe state switching circuit controls the motor to enter the active short-circuit state or the safe shutdown state via the inverter based on the active short-circuit control signal or the safe shutdown control signal.

[0099] In some specific embodiments, when the MCU is in normal working state and the MCU power module is powered normally, MCU_Status=1; the MCU will determine whether to generate an active short-circuit control signal or a safe shutdown control signal based on the collected motor speed signal or vehicle speed signal; if the MCU determines to generate an active short-circuit control signal, ASC_REQ=0, SPO_REQ=1, and the motor will enter the active short-circuit state ASC; if the MCU determines to generate a safe shutdown control signal, ASC_REQ=1, SPO_REQ=0, and the motor will enter the safe shutdown state SPO; the values ​​of ASC_REQ and SPO_REQ are valid at low level (0).

[0100] In one embodiment, the MCU is configured to generate an MCU status signal when the MCU working state is abnormal or the power supply of the MCU power module is abnormal, and send the MCU status signal to the OR gate logic circuit of the safety state control circuit, so that the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed state signal based on the MCU status signal and the speed state signal, and the MCU status signal is a low level.

[0101] Specifically, when the MCU working state is abnormal or the power supply of the MCU power module is abnormal, the MCU status signal is generated as a low level, and the generated MCU status signal is sent to the OR gate logic circuit of the safety state control circuit. The OR gate logic circuit determines the input signal of the safety state switching circuit based on the MCU status signal (low level) and the speed status signal. Since the MCU status signal is a low level, the input signal of the safety state switching circuit determined by the OR gate logic circuit is determined by the speed status signal.

[0102] Another aspect of the present application also provides a driving device.

[0103] See attached Figure 2 , Figure 21 is a schematic diagram of the main structure of a driving device according to an embodiment of the present application. In an embodiment of a driving device according to the present application, the driving device includes a motor safety state control circuit or a motor safety state control system as described in any of the above embodiments.

[0104] Another aspect of the present application provides a motor safety state control method.

[0105] See attached Figure 3 , Figure 3 FIG. 1 is a flow chart of the main steps of a motor safety state control method according to an embodiment of the present application. Figure 3 As shown, the motor safety state control method of the present application is executed based on the motor safety state control circuit or the motor safety state control system described in any of the above embodiments, and the method includes the following steps:

[0106] Step S101: Acquire a motor speed signal or a vehicle speed signal and an MCU status signal.

[0107] Specifically, during the operation of the motor safety state control system, the speed signal processing module obtains the motor speed signal or the vehicle speed signal; the motor speed signal includes but is not limited to a PWM wave signal with a fixed frequency but a duty cycle proportional to the speed, a PWM signal with a fixed duty cycle but a frequency proportional to the speed, or a voltage signal proportional to the speed. The safety state switching circuit obtains the MCU state signal, which includes a high level or a low level.

[0108] Step S102: Determine a speed state signal based on the motor speed signal or the vehicle speed signal.

[0109] For step S102, in one embodiment, the speed status signal includes a first speed status signal or a second speed status signal; determining the speed status signal based on the motor speed signal or the vehicle speed signal includes: a speed signal processing module processes the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal; a comparator determines whether the voltage signal is greater than or equal to a preset threshold, and when the voltage signal is greater than or equal to the preset threshold, outputs a first speed status signal to the safety state switching circuit; or, when the voltage signal is less than the preset threshold, outputs a second speed status signal to the safety state switching circuit.

[0110] Specifically, the speed signal processing module processes the motor speed signal or the vehicle speed signal using a corresponding signal processing method according to the acquired signal type, obtains a voltage signal representing the motor speed signal or the vehicle speed signal, and sends it to the comparator.

[0111] The comparator makes a judgment based on the received voltage signal. If the voltage signal is greater than or equal to a preset threshold, it outputs a first speed state signal and sends it to the safety state switching circuit; if the voltage signal is less than the preset threshold, it outputs a second speed state signal and sends it to the safety state switching circuit.

[0112] Step S103: The safety state switching circuit generates a first control signal or a second control signal based on the speed state signal and the MCU state signal, and controls the inverter based on the first control signal or the second control signal, and controls the motor through the inverter to enter an active short-circuit state, or a safe shutdown state, or switches between the active short-circuit state and the safe shutdown state.

[0113] For step S103, in one embodiment, the safety state switching circuit generates a first control signal or a second control signal based on the speed state signal and the MCU state signal, and controls the inverter based on the first control signal or the second control signal, and controls the motor to enter an active short-circuit state or a safe shutdown state via the inverter, or switches between the active short-circuit state and the safe shutdown state, including: when the MCU state signal is at a low level, the safety state switching circuit determines a first control signal based on the MCU state signal and the first speed state signal, and controls the inverter based on the first control signal, and controls the motor to enter an active short-circuit state via the inverter; or, when the MCU state signal is at a low level, the safety state switching circuit determines a second control signal based on the MCU state signal and the second speed state signal, and controls the inverter based on the second control signal, and controls the motor to enter a safe shutdown state via the inverter.

[0114] Specifically, when the MCU status signal is at a low level, the safety state switching circuit generates a first control signal according to the MCU status signal and the first speed state signal, and the first control signal controls the inverter and the motor to enter an active short circuit state (ASC).

[0115] When the MCU state signal is at a low level, the safety state switching circuit generates a second control signal according to the MCU state signal and the second speed state signal, and the second control signal controls the inverter and the motor to enter a safety shutdown state (SPO).

[0116] In one embodiment, after controlling the motor to enter an active short-circuit state, the method further includes: the safety state switching circuit continuously acquires a new speed state signal; when the new speed state signal is a second speed state signal, the safety state switching circuit determines a second control signal, and controls the inverter based on the second control signal, and controls the motor to enter a safe shutdown state via the inverter.

[0117] Specifically, after the motor enters the active short circuit state (ASC), the safety state switching circuit continuously obtains a new speed state signal, and when the speed state signal is the second speed state signal, generates a second control signal according to the MCU state signal and the second speed state signal. The second control signal controls the inverter and the motor to switch from the active short circuit state (ASC) to the safe shutdown state (SPO).

[0118] In one embodiment, the method also includes: when the MCU status signal is at a high level, the MCU determines an active short-circuit control signal or a safety shutdown control signal based on the motor speed signal or the vehicle speed signal, and sends the active short-circuit control signal or the safety shutdown control signal to a safety state switching circuit; the safety state switching circuit controls the inverter based on the active short-circuit control signal or the safety shutdown control signal, and controls the motor to enter an active short-circuit state or a safety shutdown state via the inverter.

[0119] Specifically, when the MCU status signal is at a high level, the MCU obtains the motor speed signal or the vehicle speed signal, and generates an active short-circuit control signal or a safe shutdown control signal based on the motor speed signal or the vehicle speed signal, and sends it to the safe state switching circuit. The safe state switching circuit controls the inverter and the motor to enter the active short-circuit state or the safe shutdown state based on the active short-circuit control signal or the safe shutdown control signal.

[0120] In summary, the present application can reasonably switch between ASC and SPO through the vehicle speed status or motor speed feedback when the MCU fails or the MCU power fails, and can meet the basic functional safety requirements of vehicle drive system applications. It can enter the SPO state at low speed, enter the ASC state at high speed, and exit the ASC state and enter the SPO state when the speed is lower than a certain value.

[0121] See attached Figure 4 , Figure 4 FIG. 1 is a schematic diagram of a detailed step flow of a motor safety state control method according to an embodiment of the present application. Figure 4 As shown, the motor safety state control method of the present application includes the following steps:

[0122] Step S201: Start;

[0123] Step S202: Acquire the motor speed signal or the vehicle speed signal and the MCU status signal.

[0124] Step S203: determining whether an MCU fault or an MCU power supply fault occurs based on the MCU status signal; if so, executing step S204; if not, executing step S211;

[0125] Step S204: performing signal processing on the motor speed signal or the vehicle speed signal to determine a corresponding voltage signal;

[0126] Step S205: determine whether the voltage signal is greater than a preset threshold, if so, execute step S206; if not, execute step S209;

[0127] Step S206: acquiring a first speed state signal, and determining a first control signal based on the first speed state signal and the MCU state signal;

[0128] Step S207: Based on the first control signal, control the inverter and the motor to enter an active short-circuit state;

[0129] Step S208: obtaining a new motor speed signal or a vehicle speed signal, and returning to execute step S204;

[0130] Step S209: acquiring a second speed state signal, and determining a second control signal based on the second speed state signal and the MCU state signal;

[0131] Step S210: Based on the second control signal, control the inverter and the motor to enter a safe shutdown state;

[0132] Step S211: determining an active short circuit control signal or a safety shutdown control signal based on a motor speed signal or a vehicle speed signal;

[0133] Step S212: Based on the active short-circuit control signal or the safety shutdown control signal, control the inverter and the motor to enter the active short-circuit state or the safety shutdown state;

[0134] Step S213: End.

[0135] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0136] It is understood by those skilled in the art that all or part of the processes in the method for implementing the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0137] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A motor safety state control circuit, applied to a vehicle drive system, characterized in that: The vehicle drive system includes an MCU and a motor, and the safety state control circuit includes a speed judgment circuit and a safety state switching circuit; the speed judgment circuit is configured to receive a motor speed signal or a vehicle speed signal and output a corresponding speed state signal; the safety state switching circuit is configured to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state based on the speed state signal and the MCU state signal.

2. The motor safety state control circuit according to claim 1, characterized in that: The safety state control circuit also includes an OR gate logic circuit, which is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, so that the safety state switching circuit outputs a corresponding control signal based on the input signal to control the safety state of the motor to an active short circuit state, or a safe shutdown state, or to switch between the active short circuit state and the safe shutdown state.

3. The motor safety state control circuit according to claim 2, characterized in that: The OR gate logic circuit is configured to determine the input signal of the safety state switching circuit based on the MCU state signal and the speed state signal output by the speed judgment circuit, including: When the MCU status signal is at a high level, the high level indicates that the MCU is in a normal working state and the MCU is powered normally, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the MCU status signal, and the safety state switching circuit outputs a corresponding control signal based on the MCU status signal; When the MCU status signal is at a low level, the low level indicates that the MCU is faulty or the MCU power is off, the OR gate logic circuit determines that the input signal of the safety state switching circuit is the speed state signal, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal.

4. The motor safety state control circuit according to claim 3, characterized in that: The speed status signal includes a first speed status signal or a second speed status signal, and the speed judgment circuit includes a comparator, which is configured to obtain the motor speed signal or the vehicle speed signal, and judge whether the motor speed signal or the vehicle speed signal is greater than or equal to a corresponding preset threshold value, and output a first speed status signal when the motor speed signal or the vehicle speed signal is greater than or equal to the corresponding preset threshold value; or output a second speed status signal when the motor speed signal or the vehicle speed signal is less than the corresponding preset threshold value.

5. The motor safety state control circuit according to claim 4, characterized in that: The vehicle drive system further includes an inverter and a drive circuit, and the safety state switching circuit outputs a corresponding control signal based on the speed state signal, including: When the speed state signal is a first speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a first control signal to the inverter, so that the inverter controls the motor to enter an active short-circuit state based on the first control signal; or, When the speed state signal is a second speed state signal, the safety state switching circuit controls the drive circuit to enter a first disabled state, and outputs a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal; the first disabled state prohibits the drive circuit from controlling the inverter to drive the motor to work.

6. The motor safety state control circuit according to claim 5, characterized in that: The safety state switching circuit is also configured to continuously obtain a new speed state signal after controlling the motor to enter an active short-circuit state, and when the new speed state signal is a second speed state signal, output a second control signal to the inverter, so that the inverter controls the motor to enter a safe shutdown state based on the second control signal.

7. The motor safety state control circuit according to claim 4, characterized in that: The speed judgment circuit also includes a speed signal processing module, which is configured to obtain a motor speed signal or a vehicle speed signal, process the motor speed signal or the vehicle speed signal to obtain a corresponding voltage signal, and output the voltage signal to the comparator, so that the comparator outputs the speed status signal based on the voltage signal.

8. The motor safety state control circuit according to claim 7, characterized in that: The safety state control circuit further includes a first power supply module, which is configured to supply power to the speed signal processing module and the safety state switching circuit.

9. A motor safety state control system, characterized in that: The system comprises a motor safety state control circuit and a vehicle drive system as claimed in any one of claims 1 to 8; The vehicle drive system includes an MCU, an MCU power module, an inverter and a motor. The motor safety state control circuit and the MCU are connected in parallel to jointly control the inverter, and the motor is controlled via the inverter; wherein, when the MCU is in normal working state and the MCU power module is powered normally, the MCU controls the motor to operate via the inverter; when the MCU is in abnormal working state or the MCU power module is powered abnormally, the motor safety state control circuit controls the inverter based on the speed state signal, and controls the motor to be in an active short circuit state, or a safe shutdown state, or switches between the active short circuit state and the safe shutdown state via the inverter.

10. The motor safety state control system according to claim 9, characterized in that: The vehicle drive system also includes a drive circuit, which is configured to control the inverter to drive the motor to work through the drive circuit when the MCU is in normal working state and the MCU power module is powered normally, and generate an MCU status signal, and send the MCU status signal to the safety state control circuit, so that the safety state control circuit enters a second disabled state based on the MCU status signal, and the MCU status signal is a high level. The second disabled state prohibits the safety state switching circuit from obtaining the speed status signal.

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