A control method and system for a three-phase circuit breaker of an electric drive system

Abstract

The application discloses a kind of electric drive system three-phase circuit breaker control method and system, comprising the following steps: real-time acquisition in electric drive system collision signal, fault signal and motor operating state signal;When there are any two signals in collision signal, fault signal and motor operating state signal are effective flag bits, the electric drive system is graded risk assessment based on preset hierarchical risk assessment strategy, to output the protection instruction of electric drive system;The protection instruction includes primary response instruction, secondary response instruction and tertiary response instruction;According to the level of the protection instruction, corresponding torque limit, PWM frequency adjustment or motor mode switching operation is executed, to control three-phase circuit breaker to complete the hierarchical protection of electric drive system.The method and system of the present application significantly improve the safety and reliability of electric drive system.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle electric drive system safety technology, and in particular to a three-phase circuit breaker control method and system for an electric drive system. Background Technology

[0002] With the rapid development of new energy vehicles, the reliability and safety of the motor control module, as a core component of the electric drive system, are of paramount importance. Three-phase circuit breakers serve as critical protection devices within the motor control module, requiring rapid circuit disconnection under fault conditions such as short circuits, overloads, and collisions to prevent serious malfunctions like power module damage and motor winding burnout. However, existing circuit breaker control technologies suffer from numerous problems. For instance, current technologies have insufficient response speeds; traditional electromagnetic circuit breakers have a mechanical tripping time >20ms, and electronic protection algorithms (RMS calculation) have a delay >10ms, failing to meet the μs-level short-circuit requirements of SiC power devices (e.g., short-circuit current rise rate >10kA / μs on an 800V platform). Furthermore, existing technologies have fixed protection thresholds, cannot distinguish between motor stall and normal start-up, and lack linkage with airbag sensors and BMS high-voltage interlocking (disconnection delay after collision >50ms), making it difficult to meet the high dynamic and high safety requirements of new energy vehicles.

[0003] Therefore, how to improve the response speed of circuit breaker control, enhance its adaptability to operating conditions, and achieve intelligent linkage of multiple systems has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the technical problems existing in the background art, this invention proposes a three-phase circuit breaker control method and system for an electric drive system.

[0005] The present invention proposes a three-phase circuit breaker control method for an electric drive system, comprising the following steps:

[0006] Real-time acquisition of collision signals, fault signals, and motor operating status signals from the electric drive system;

[0007] When any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, the electric drive system is subjected to a graded risk assessment based on a preset graded risk assessment strategy, so as to output a protection command for the electric drive system; the protection command includes a first-level response command, a second-level response command, and a third-level response command.

[0008] According to the level of the protection command, the corresponding torque limiting, PWM frequency adjustment or motor mode switching operation is executed to control the three-phase circuit breaker to complete the hierarchical protection of the electric drive system.

[0009] Preferably, the preset graded risk assessment strategy specifically includes:

[0010] When the detected temperature of the SiC module in the electric drive system exceeds a preset first threshold, a first-level response command is generated.

[0011] When the detected current imbalance rate of the three-phase current is greater than the preset second threshold and lasts for x ms, or the bus voltage fluctuation is greater than the preset third threshold and lasts for y ms, a second-level response command is generated.

[0012] When the collision signal and / or fault signal are valid flag bits, and the hardware current in the electric drive system is greater than the preset fourth threshold, a level three response command is generated.

[0013] Preferably, when the protection command is specifically a first-level response command, the motor torque in the electric drive system is limited to 300 Nm.

[0014] Preferably, when the protection command is specifically a secondary response command, the PWM carrier frequency in the electric drive system is reduced in a stepwise manner. Specifically, when the current imbalance rate is between 15% and 20%, the PWM carrier frequency is reduced from 10kHz to 8kHz; when the current imbalance rate is greater than 20%, the PWM carrier frequency is reduced from 10kHz to 5kHz.

[0015] Preferably, when the protection command is a three-level response command, if the motor speed is <1500rpm, the motor in the electric drive system is controlled to enter the free coasting mode; if the motor speed is ≥1500rpm, the motor is controlled to enter the active short circuit mode; if both the collision signal and the fault signal are valid flag bits, the circuit breaker in the electric drive system is controlled to disconnect.

[0016] Preferably, the collision signal is a hard-wired signal from the airbag control module or collision sensor in the electric drive system after de-jitter filtering; the fault signal includes CAN message signals for battery overheating, sensor failure, and abnormal torque; the motor operating status signal includes motor speed, bus voltage, phase current, and SiC module temperature.

[0017] Preferably, it further includes:

[0018] When any one of the collision signal, fault signal, and motor operating status signal triggers the valid flag bit, the system checks the other two types of signals in parallel. If any one of the other two types of signals triggers the valid flag bit at the same time, the circuit breaker will be tripped; otherwise, the current state will be maintained and no action will be taken.

[0019] This invention proposes a three-phase circuit breaker control system for an electric drive system, comprising:

[0020] The signal acquisition module is used to acquire collision signals, fault signals, and motor operating status signals in the electric drive system in real time.

[0021] The control module is used to perform a graded risk assessment of the electric drive system based on a preset graded risk assessment strategy when any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, and output protection commands for the electric drive system; the protection commands include a first-level response command, a second-level response command, and a third-level response command.

[0022] The output module is used to perform corresponding torque limiting, PWM frequency adjustment or motor mode switching operations according to the level of the protection command, so as to control the three-phase circuit breaker to complete the hierarchical protection of the electric drive system.

[0023] This invention presents a three-phase circuit breaker control method and system for an electric drive system. This scheme, through an electro-mechanical hybrid breaking architecture, combined with a graded risk assessment safety decision-making mechanism, anti-false trigger verification, and multi-signal linkage control, achieves short-circuit protection, high-voltage arc suppression, and aging self-adaptation for the SiC module, significantly improving the safety and reliability of the electric drive system. Through graded protection logic and dynamic threshold adjustment, different fault types and motor operating states can be identified, distinguishing between motor stall and normal start-up, and taking corresponding protection actions for different fault levels, improving the system's adaptability to complex operating conditions. Linked with multiple systems such as airbag sensors, BMS, and VCU, the circuit breaker breaks after a collision signal trigger, solving the problem of delayed breaking after a collision in existing technologies. It possesses a comprehensive anti-false trigger mechanism, ensuring the safe and reliable operation of the system. Attached Figure Description

[0024] Figure 1 This is a schematic diagram illustrating the workflow of a three-phase circuit breaker control method for an electric drive system proposed in this invention.

[0025] Figure 2 This is a schematic diagram of the system architecture of a three-phase circuit breaker control system for an electric drive system proposed in this invention;

[0026] Figure 3 This is a schematic diagram of one embodiment of a three-phase circuit breaker control system for an electric drive system proposed in this invention;

[0027] Figure 4 This is a waveform diagram illustrating one embodiment of a three-phase circuit breaker control system for an electric drive system proposed in this invention. Detailed Implementation

[0028] Reference Figure 1-4 The present invention proposes a three-phase circuit breaker control method for an electric drive system, comprising the following steps:

[0029] S1. Real-time acquisition of collision signals, fault signals, and motor operating status signals in the electric drive system.

[0030] Specifically, the collision signal is the hard-wired signal of the airbag control module or collision sensor in the electric drive system after de-jitter filtering; the fault signal includes CAN message signals for battery overheating, sensor failure, and abnormal torque; the motor operating status signal includes motor speed, bus voltage, phase current, and SiC module temperature.

[0031] S2. When any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, the electric drive system is subjected to a graded risk assessment based on a preset graded risk assessment strategy, so as to output protection instructions for the electric drive system; the protection instructions include level one response instructions, level two response instructions, and level three response instructions.

[0032] In this embodiment, the preset graded risk assessment strategy specifically includes:

[0033] When the detected temperature of the SiC module in the electric drive system exceeds a preset first threshold, a first-level response command is generated.

[0034] When the detected current imbalance rate of the three-phase current is greater than the preset second threshold and lasts for x ms, or the bus voltage fluctuation is greater than the preset third threshold and lasts for y ms, a second-level response command is generated.

[0035] When the collision signal and / or fault signal are valid flag bits, and the hardware current in the electric drive system is greater than the preset fourth threshold, a level three response command is generated.

[0036] Specifically, the preset first threshold is 105℃, and the threshold is adjustable. When the detected three-phase current imbalance rate is greater than 15% and lasts for 10ms, or the bus voltage fluctuation is greater than ±10% and lasts for 5ms, a secondary response command is generated.

[0037] In this embodiment, when the protection command is specifically a Level 1 response command, the motor torque in the electric drive system is limited to 300 Nm.

[0038] In this embodiment, when the protection command is specifically a level-two response command, the PWM carrier frequency in the electric drive system is reduced in a stepwise manner. Specifically, when the current imbalance rate is between 15% and 20%, the PWM carrier frequency is reduced from 10kHz to 8kHz; when the current imbalance rate is greater than 20%, the PWM carrier frequency is reduced from 10kHz to 5kHz.

[0039] In this embodiment, when the protection command is specifically a three-level response command, if the motor speed is <1500rpm, the motor in the electric drive system is controlled to enter the free coasting mode; if the motor speed is ≥1500rpm, the motor is controlled to enter the active short circuit mode; if both the collision signal and the fault signal are valid flag bits, the circuit breaker in the electric drive system is controlled to disconnect.

[0040] S3. Based on the protection command level, execute the corresponding torque limiting, PWM frequency adjustment or motor mode switching operations to control the three-phase circuit breaker to complete the graded protection of the electric drive system.

[0041] In this embodiment, it also includes:

[0042] S4. When any one of the collision signal, fault signal and motor running status signal triggers the valid flag bit, the system checks the other two types of signals in parallel. If any one of the other two types of signals triggers the valid flag bit at the same time, the circuit breaker will be tripped; otherwise, the current state will be maintained and no action will be taken.

[0043] In this embodiment, the method further includes: storing the protection operation that occurred in a non-volatile memory (MSC); and sending the fault code to the vehicle network via CANFD.

[0044] Reference Figure 1-4 The present invention proposes a three-phase circuit breaker control system for an electric drive system, comprising:

[0045] The signal acquisition module is used to acquire collision signals, fault signals, and motor operating status signals in the electric drive system in real time.

[0046] The control module is used to perform a graded risk assessment of the electric drive system based on a preset graded risk assessment strategy when any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, and output protection commands for the electric drive system; the protection commands include first-level response commands, second-level response commands, and third-level response commands.

[0047] The output module is used to perform corresponding torque limiting, PWM frequency adjustment or motor mode switching operations according to the protection command level, so as to control the three-phase circuit breaker to complete the hierarchical protection of the electric drive system.

[0048] Specifically, the circuit breaker employs a hybrid breaking strategy: first, electronic breaking is achieved through the MOSFETs on the SiC module (response time < 1 μs); then, mechanical breaking is completed through a magnetic blowout mechanism (action time < 2 ms). The circuit breaker can use either a magnetizing fuse or a pyrotechnic circuit breaker. For example... Figure 3 As shown, the control module uses a dual-core lockstep MCU to achieve signal redundancy processing. Emergency tripping is directly triggered via a hardware comparator (CMP) within the control module. A safety state holding circuit ensures the contacts are in the open position after power failure. The time from collision signal triggering to complete circuit breaker disconnection is ≤3ms; it coordinates with the BMS high-voltage interlock with an error ≤±100μs.

[0049] In this embodiment, a current sensor is installed between the circuit breaker and the control module to provide feedback on changes in the circuit breaker's breaking current, such as... Figure 4The figure shown is a waveform diagram of one embodiment of circuit breaker breaking test, in which the phase current is 100A.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A three-phase circuit breaker control method for an electric drive system, characterized in that, Includes the following steps: Real-time acquisition of collision signals, fault signals, and motor operating status signals from the electric drive system; When any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, the electric drive system is subjected to a graded risk assessment based on a preset graded risk assessment strategy, so as to output a protection command for the electric drive system; the protection command includes a first-level response command, a second-level response command, and a third-level response command. According to the level of the protection instruction, the corresponding torque limiting, PWM frequency adjustment or motor mode switching operation is executed to control the three-phase circuit breaker to complete the graded protection of the electric drive system. The pre-defined risk assessment strategy specifically includes: When the detected temperature of the SiC module in the electric drive system exceeds a preset first threshold, a first-level response command is generated. When the detected current imbalance rate of the three-phase current is greater than the preset second threshold and lasts for x ms, or the bus voltage fluctuation is greater than the preset third threshold and lasts for y ms, a second-level response command is generated. When the collision signal and / or fault signal are valid flag bits, and the hardware current in the electric drive system is greater than the preset fourth threshold, a level three response command is generated.

2. The three-phase circuit breaker control method for an electric drive system according to claim 1, characterized in that, When the protection command is specifically a Level 1 response command, the motor torque in the electric drive system is limited to 300 Nm.

3. The three-phase circuit breaker control method for an electric drive system according to claim 1, characterized in that, When the protection command is specifically a level-two response command, the PWM carrier frequency in the electric drive system is reduced in a stepwise manner. Specifically, when the current imbalance rate is between 15% and 20%, the PWM carrier frequency is reduced from 10kHz to 8kHz; when the current imbalance rate is greater than 20%, the PWM carrier frequency is reduced from 10kHz to 5kHz.

4. The three-phase circuit breaker control method for an electric drive system according to claim 1, characterized in that, When the protection command is specifically a three-level response command, if the motor speed is <1500rpm, the motor in the electric drive system is controlled to enter the free coasting mode; if the motor speed is ≥1500rpm, the motor is controlled to enter the active short circuit mode; if both the collision signal and the fault signal are valid flag bits, the circuit breaker in the electric drive system is controlled to disconnect.

5. The three-phase circuit breaker control method for an electric drive system according to claim 1, characterized in that, in, The collision signal is the hard-wired signal of the airbag control module or collision sensor in the electric drive system after de-jitter filtering; the fault signal includes CAN message signals for battery overheating, sensor failure, and abnormal torque; the motor operating status signal includes motor speed, bus voltage, phase current, and SiC module temperature.

6. The three-phase circuit breaker control method for an electric drive system according to claim 1, characterized in that, Also includes: When any one of the collision signal, fault signal, and motor operating status signal triggers the valid flag bit, the system checks the other two types of signals in parallel. If any one of the other two types of signals triggers the valid flag bit at the same time, the circuit breaker will be tripped; otherwise, the current state will be maintained and no action will be taken.

7. A three-phase circuit breaker control system for an electric drive system, characterized in that, include: The signal acquisition module is used to acquire collision signals, fault signals, and motor operating status signals in the electric drive system in real time. The control module is used to perform a graded risk assessment of the electric drive system based on a preset graded risk assessment strategy when any two of the collision signal, fault signal, and motor operating status signal are valid flag bits, and output protection commands for the electric drive system; the protection commands include a first-level response command, a second-level response command, and a third-level response command. The output module is used to perform corresponding torque limiting, PWM frequency adjustment or motor mode switching operations according to the level of the protection instruction, so as to control the three-phase circuit breaker to complete the hierarchical protection of the electric drive system. The pre-defined risk assessment strategy specifically includes: When the detected temperature of the SiC module in the electric drive system exceeds a preset first threshold, a first-level response command is generated. When the detected current imbalance rate of the three-phase current is greater than the preset second threshold and lasts for x ms, or the bus voltage fluctuation is greater than the preset third threshold and lasts for y ms, a second-level response command is generated. When the collision signal and / or fault signal are valid flag bits, and the hardware current in the electric drive system is greater than the preset fourth threshold, a level three response command is generated.

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