Method for diagnosing and processing bus voltage by motor controller

Abstract

The invention discloses a diagnosis processing method of a motor controller to bus voltage, a motor controller IPU not only collects bus voltage through a built-in first sampling circuit and a built-in second sampling circuit, but also obtains bus voltage collected by a BMS and a DC / DC converter through a CAN line, sampling is abundant, misjudgment caused by sampling faults of the IPU can be avoided, and in addition, the diagnosis processing method of the motor controller to the bus voltage is more accurate. The IPU performs continuous logic judgment according to a first bus voltage, a second bus voltage, a third bus voltage and a fourth bus voltage which are acquired by the first sampling circuit, the second sampling circuit, the BMS and the DC / DC converter respectively, can judge a bus voltage fault as a plurality of fault levels according to fault conditions, and executes a corresponding fault processing mode according to the fault levels. The bus voltage fault judgment and processing modes of the IPU are abundant; therefore, the problem that the reliability of bus voltage monitoring and fault judgment of the current motor controller is poor can be effectively solved, and the reliability and the stability of motor control can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor control methods in electrical engineering, and in particular relates to a method for diagnosing and processing bus voltage by a motor controller. Background Art

[0002] Electric vehicles are new energy vehicles that use batteries to power motors and other electrical systems. The main line through which the battery of an electric vehicle directly outputs electricity is called the busbar, to which are connected electrical equipment such as the BMS (battery management system), DC / DC converter, and IPU (motor controller). The BMS is used to monitor the battery's status, such as voltage, temperature, and charge and discharge current, to ensure the battery operates safely and efficiently. The DC / DC converter is used to convert high-voltage direct current from the battery into low-voltage direct current, thereby powering low-voltage systems on the vehicle, such as lighting. The IPU is used to convert the direct current output of the battery into alternating current for driving the motor, and to adjust the speed and torque of the motor according to driving requirements.

[0003] To ensure the safety and effectiveness of motor control, the IPU also monitors the bus voltage through a built-in sampling circuit. When an abnormal bus voltage is detected, the IPU will take corresponding measures to protect the motor and other related components. For example, the method for handling bus voltage failures disclosed in the motor controller of Chinese patent CN105141214A monitors the bus voltage through the IPU. When the voltage value is within a preset range, normal motor control is performed. When the voltage value is greater than the preset maximum value or less than the minimum value, the motor enters a fault mode, sets the given torque to zero, calculates the motor back EMF, and determines whether the motor back EMF voltage is higher than the bus voltage at this time. If yes, the IPU actively controls the voltage difference to increase the DC bus voltage, otherwise it turns off the IGBT and stops motor control. Although this method can avoid sudden changes in bus voltage by actively controlling the voltage change rate, it only monitors the bus voltage through the IPU sampling circuit. Not only is the sampling single, it is easy to cause misjudgment due to sampling circuit failure, thereby affecting the safety and stability of motor control. In addition, the fault judgment and processing methods are single, which easily affects the reliability of motor control. Therefore, it is necessary to design a bus voltage diagnosis and processing method that monitors bus voltage, judges and processes faults more comprehensively and reliably to improve the reliability and stability of motor control. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for diagnosing and processing bus voltage by a motor controller, so as to solve the technical problem that the reliability of the current motor controller in monitoring bus voltage and making fault judgments is poor, thereby achieving the effect of improving the reliability and stability of motor control.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for diagnosing bus voltage by a motor controller is provided. The method is based on a monitoring circuit, wherein the monitoring circuit includes a bus and a CAN line. The bus is electrically connected to a BMS, a DC / DC converter, and an IPU. The BMS and the DC / DC converter are respectively communicatively connected to the IPU via the CAN line. The IPU has a first sampling circuit and a second sampling circuit, respectively electrically connected to the bus. The method comprises the following steps: S1: Obtain bus voltage: The IPU obtains the first bus voltage through the first sampling circuit, obtains the second bus voltage through the second sampling circuit, obtains the third bus voltage sent by the DC / DC converter through the CAN line, and obtains the fourth bus voltage sent by the BMS through the CAN line; S2: Fault judgment and processing: The IPU judges the fault level according to the first bus voltage, the second bus voltage, the third bus voltage and the fourth bus voltage and performs corresponding processing according to the fault level.

[0006] Furthermore, S2 includes the following sub-steps: S21: Performing a primary fault judgment based on the first bus voltage. If the result is false, the bus voltage is judged to be fault-free. If the result is true, performing a secondary fault judgment based on the first bus voltage. If the result is false, it is judged to be a primary fault and primary processing is performed. If the result is true, proceeding to the next step. S22: Performing a level 3 fault judgment based on the second bus voltage. If the result is false, it is judged as a level 2 fault and the level 2 processing is performed. If the result is true, performing a level 4 fault judgment based on the second bus voltage. If the result is false, it is judged as a level 3 fault and the level 3 processing is performed. If the result is true, proceeding to the next step. S23: Perform a level 5 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 4 fault and the level 4 process is performed. If the result is true, perform a level 6 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 5 fault and the level 5 process is performed. If the result is true, proceed to the next step. S24: Perform a level 7 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 6 fault and level 6 processing is performed. If the result is true, perform an level 8 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 7 fault and level 7 processing is performed. If the result is true, it is judged as a level 8 fault and level 8 processing is performed.

[0007] Furthermore, in S21, the first-level fault judgment is performed based on the first bus voltage: when the ignition signal validity time exceeds the set time T01, the high voltage on the system exceeds the set time T02, and any one of the first-level fault conditions is met, the result of the first-level fault judgment is true, otherwise it is false; the first-level fault conditions include: 1) the first bus voltage is greater than the set threshold V11 and less than the set threshold V12, and the maintenance time exceeds the set time T11, 2) the first bus voltage is greater than the set threshold V12, and the maintenance time exceeds the set time T12, 3) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV11 and less than the set threshold dV12, and the number of times exceeds the set number N11 within the set time T13, 4) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N12 within the set time T14, 5) the first bus voltage is less than the set threshold V13, and the maintenance time exceeds the set time T15; The specific secondary fault judgment based on the first bus voltage is: when any secondary fault condition is met, the result of the secondary fault judgment is true, otherwise it is false; the secondary fault conditions include: 1) the first bus voltage is greater than the set threshold V12, and the maintenance time exceeds the set time T16, 2) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N13 within the set time T17.

[0008] Furthermore, in S22, the three-level fault judgment is performed based on the second bus voltage: when any three-level fault condition is met, the result of the three-level fault judgment is true, otherwise it is false; the three-level fault conditions include: 1) the second bus voltage is greater than the set threshold V21 and less than the set threshold V22, and the maintenance time exceeds the set time T21, 2) the second bus voltage is greater than the set threshold V22, and the maintenance time exceeds the set time T22, 3) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV21 and less than the set threshold dV22, and the number of times exceeds the set number N21 within the set time T23, 4) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N22 within the set time T24, 5) the second bus voltage is less than the set threshold V23, and the maintenance time exceeds the set time T25; The four-level fault judgment based on the second bus voltage is specifically: when any of the four-level fault conditions is met, the result of the four-level fault judgment is true, otherwise it is false; the four-level fault conditions include: 1) the second bus voltage is greater than the set threshold V22, and the maintenance time exceeds the set time T25, 2) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N23 within the set time T26.

[0009] Furthermore, in S23, the five-level fault judgment is performed based on the third bus voltage. Specifically, when any of the five-level fault conditions is met, the result of the five-level fault judgment is true, otherwise it is false. The five-level fault conditions include: 1) the third bus voltage is greater than the set threshold V31 and less than the set threshold V32, and the holding time exceeds the set time T31; 2) the third bus voltage is greater than the set threshold V32, and the holding time exceeds the set time T32; 3) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV31 and less than the set threshold dV32, and the number of times exceeds the set number N31 within the set time T33; 4) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N32 within the set time T34; 5) the third bus voltage is less than the set threshold V33, and the holding time exceeds the set time T35; The specific six-level fault judgment based on the third bus voltage is: when any six-level fault conditions are met, the result of the six-level fault judgment is true, otherwise it is false; the six-level fault conditions include: 1) the third bus voltage is greater than the set threshold V32, and the maintenance time exceeds the set time T35, 2) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N33 within the set time T36.

[0010] Furthermore, in S24, the seven-level fault judgment is performed based on the fourth bus voltage. Specifically, when any of the seven-level fault conditions is met, the result of the seven-level fault judgment is true, otherwise it is false. The seven-level fault conditions include: 1) the fourth bus voltage is greater than the set threshold V41 and less than the set threshold V42, and the maintenance time exceeds the set time T41; 2) the fourth bus voltage is greater than the set threshold V42, and the maintenance time exceeds the set time T42; 3) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV41 and less than the set threshold dV42, and the number of times exceeds the set number N41 within the set time T43; 4) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N42 within the set time T44; 5) the fourth bus voltage is less than the set threshold V43, and the maintenance time exceeds the set time T45; The eight-level fault judgment based on the fourth bus voltage is specifically: when any of the eight-level fault conditions is met, the result of the eight-level fault judgment is true, otherwise it is false; the eight-level fault conditions include: 1) the fourth bus voltage is greater than the set threshold V42, and the maintenance time exceeds the set time T45, 2) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N43 within the set time T46.

[0011] Furthermore, in S2, when the IPU performs the first-level processing, the second-level processing, the third-level processing, the fourth-level processing, the fifth-level processing, the sixth-level processing, and the seventh-level processing, the IPU maintains the normal mode, and the output torque of the motor controlled by the IPU is reduced from the current value to zero according to the set slope. The corresponding formula is: T= -K n ×t+T0 Where T represents the output torque of the motor, K n represents the set slope of the corresponding processing, {n∈Z|1≤x≤7}, t represents the duration of the fault, and T0 represents the output torque of the motor when the corresponding processing is executed.

[0012] Furthermore, in S2, when the IPU performs the eight-level processing, the IPU switches to the fault mode. When the motor speed is greater than the set threshold R, the ASC processing is performed, otherwise the FW processing is performed.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The motor controller of the present invention provides a diagnostic processing method for bus voltage. The motor controller IPU not only collects bus voltage through the built-in first sampling circuit and second sampling circuit, but also obtains the bus voltage collected by the BMS and DC / DC converter through the CAN line. The rich sampling can avoid the IPU from making misjudgments due to its own sampling failure, which is beneficial to improving the safety and stability of motor control. In addition, the IPU performs continuous logical judgment based on the first bus voltage, the second bus voltage, the third bus voltage and the fourth bus voltage collected respectively by the first sampling circuit, the second sampling circuit, the BMS and the DC / DC converter, and can judge the bus voltage fault as multiple fault levels according to the fault situation. The IPU executes the corresponding fault processing method according to the fault level. The IPU has rich methods for judging and processing bus voltage faults, which is beneficial to improving the reliability of the IPU in controlling the motor. Therefore, the present invention can effectively solve the problem of poor reliability of the current motor controller in monitoring bus voltage and making fault judgments, which is beneficial to improving the reliability and stability of motor control. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the monitoring circuit described in the embodiment; Figure 2 A flowchart of the diagnostic processing method described in the embodiment; DETAILED DESCRIPTION

[0015] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0016] Example: See Figure 1A method for diagnosing bus voltage by a motor controller is provided. The method is based on a monitoring circuit, wherein the monitoring circuit includes a bus and a CAN line. A BMS, a DC / DC converter, and an IPU are electrically connected to the bus. The BMS and the DC / DC converter are respectively communicatively connected to the IPU via the CAN line. The IPU includes a first sampling circuit and a second sampling circuit, each of which is electrically connected to the bus. In this embodiment, the IPU also includes an MCU and a CAN driver module. The MCU (Motor Control Unit) is the motor control unit of the IPU, which is used to perform tasks such as 1) controlling the speed and torque of the motor, 2) realizing the energy recovery (regenerative braking) function, 3) monitoring the state parameters of the motor, such as temperature, speed and position, and 4) adjusting the working mode of the motor according to demand to optimize performance and efficiency. By receiving instructions from other vehicle systems and data fed back by sensors, the MCU accurately controls the behavior of the motor to ensure that the power output of the electric vehicle meets the driver's expectations and maximizes energy efficiency. The MCU is electrically connected to the first sampling circuit, the second sampling circuit and the CAN driver module respectively, and the IPU is connected to the CAN line communication through the CAN driver module. The main function of the BMS is to monitor and manage the battery, including monitoring parameters such as voltage, current, temperature, etc., balancing the charge state of each battery cell in the battery to prevent overcharging or over-discharging, and optimizing the energy efficiency of the entire battery pack, thereby ensuring To ensure the safety, life and performance of the battery, in order to grasp the voltage status of the battery to perform the above tasks, the BMS itself has the function of collecting the bus voltage, and will also perform the task of collecting the bus voltage when working; the DC / DC converter is used to convert the high-voltage DC power from the battery into low-voltage DC power, thereby powering the low-voltage systems such as lighting in the car. In order to accurately control the output voltage and ensure the stability and safety of the conversion process, the DC / DC converter itself also has the function of collecting the bus voltage, and will also perform the task of collecting the bus voltage when working; in the monitoring circuit, the BMS will collect the bus voltage and send the collected data to the CAN line, and the DC / DC converter will also collect the bus voltage and send the collected data to the CAN line. In addition to obtaining the bus voltage through the first sampling circuit and the second sampling circuit, the MCU also obtains the bus voltage collected by the BMS and the DC / DC converter from the CAN line through the CAN driver module.

[0017] See Figure 2 , the diagnostic processing method comprises the following steps: S1: Obtain bus voltage: The IPU obtains the first bus voltage through the first sampling circuit, obtains the second bus voltage through the second sampling circuit, obtains the third bus voltage sent by the DC / DC converter through the CAN line, and obtains the fourth bus voltage sent by the BMS through the CAN line; S2: Fault judgment and processing: The IPU judges the fault level according to the first bus voltage, the second bus voltage, the third bus voltage and the fourth bus voltage and performs corresponding processing according to the fault level.

[0018] The motor controller of the present invention provides a diagnostic processing method for bus voltage. The motor controller IPU not only collects bus voltage through the built-in first sampling circuit and second sampling circuit, but also obtains the bus voltage collected by the BMS and DC / DC converter through the CAN line. The rich sampling can avoid the IPU from making misjudgments due to its own sampling failure, which is beneficial to improving the safety and stability of motor control. In addition, the IPU performs continuous logical judgment based on the first bus voltage, the second bus voltage, the third bus voltage and the fourth bus voltage collected respectively by the first sampling circuit, the second sampling circuit, the BMS and the DC / DC converter, and can judge the bus voltage fault as multiple fault levels according to the fault situation. The IPU executes the corresponding fault processing method according to the fault level. The IPU has rich methods for judging and processing bus voltage faults, which is beneficial to improving the reliability of the IPU in controlling the motor. Therefore, the present invention can effectively solve the problem of poor reliability of the current motor controller in monitoring bus voltage and making fault judgments, which is beneficial to improving the reliability and stability of motor control.

[0019] See Figure 2 , S2 includes the following sub-steps: S21: Perform a first-level fault judgment based on the first bus voltage. If the result is false, it is judged that the bus voltage has no fault. If the result is true, perform a second-level fault judgment based on the first bus voltage. If the result is false, it is judged as a first-level fault and executes first-level processing. If the result is true, proceed to S22.

[0020] In S21, the first-level fault judgment is performed based on the first bus voltage. Specifically, if the ignition signal valid time exceeds the set time T01, the high voltage on the system exceeds the set time T02, and any first-level fault condition is met, the result of the first-level fault judgment is true, otherwise it is false. The first-level fault conditions include: 1) the sampled value of the first bus voltage is greater than the set threshold V11 and less than the set threshold V12, and the retention time exceeds the set time T11; 2) the sampled value of the first bus voltage is greater than the set threshold V12, and the retention time exceeds the set time T12; 3) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV11 and less than the set threshold dV12, and the number of times exceeds the set number N11 within the set time T13; 4) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N12 within the set time T14; 5) the first bus voltage is less than the set threshold V13, and the retention time exceeds the set time T15; The specific secondary fault judgment based on the first bus voltage is: when the result of the first bus fault judgment is true and any secondary fault condition is met, the result of the secondary fault judgment is true, otherwise it is false; the secondary fault conditions include: 1) the sampling value of the first bus voltage is greater than the set threshold V12, and the holding time exceeds the set time T16, 2) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N13 within the set time T17.

[0021] In S21, the fluctuation amplitude of the first bus voltage is calculated using the following formula: ΔV1=V1A-V1B Wherein, ΔV1 represents the fluctuation amplitude of the first bus voltage, V1A and V1B represent the first bus voltages of two sampling cycles respectively, the sampling time of the first bus voltage V1B is before the first bus voltage V1A, and the sampling interval is 1ms. In S21, the number of fluctuations is calculated as follows: when the fluctuation amplitude meets the threshold range, the software accumulates 1 per operation cycle, with a maximum value of 65535; when it does not meet the threshold range, the software decrements 1 per operation cycle, with a minimum value of 0; During implementation, the thresholds V11, V12, V13, dV11, and dV12 are set, the times T01, T02, T11, T12, T13, T14, T15, T16, and T17 are set, and the number of times N11, N12, and N13 are set. These can be set according to different system requirements or hardware characteristics. In this embodiment, the thresholds V11=480V, V12=520V, V13=200V, dV11=15V, and dV12=20V are set, the times T01=400ms, T02=100ms, T11=50ms, T12=50ms, T13=150ms, T14=150ms, T15=50ms, T16=50ms, and T17=150ms are set, and the number of times N11=5, N12=5, and N13=10 are set.

[0022] S22: Perform a third-level fault judgment based on the second bus voltage. If the result is false, it is judged as a second-level fault and executes the second-level processing. If the result is true, perform a fourth-level fault judgment based on the second bus voltage. If the result is false, it is judged as a third-level fault and executes the third-level processing. If the result is true, proceed to S23.

[0023] In S22, the third-level fault judgment is performed based on the second bus voltage: when the result of the second-level fault judgment is true and any of the third-level fault conditions is met, the result of the third-level fault judgment is true, otherwise it is false; the third-level fault conditions include: 1) the sampled value of the second bus voltage is greater than the set threshold V21 and less than the set threshold V22, and the holding time exceeds the set time T21; 2) the sampled value of the second bus voltage is greater than the set threshold V22, and the holding time exceeds the set time T22; 3) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV21 and less than the set threshold dV22, and the number of times exceeds the set number N21 within the set time T23; 4) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N22 within the set time T24; 5) the second bus voltage is less than the set threshold V23, and the holding time exceeds the set time T25; The four-level fault judgment based on the second bus voltage is specifically: when the result of the third-level fault judgment is true and any of the four-level fault conditions is met, the result of the fourth-level fault judgment is true, otherwise it is false; the four-level fault conditions include: 1) the sampling value of the second bus voltage is greater than the set threshold V22, and the maintenance time exceeds the set time T26, 2) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N23 within the set time T27.

[0024] In S22, the fluctuation amplitude of the second bus voltage is calculated using the following formula: ΔV2=V2A-V2B Wherein, ΔV2 represents the fluctuation amplitude of the second bus voltage, V2A and V2B represent the second bus voltages of two sampling cycles respectively, the sampling time of the second bus voltage V2B is before the second bus voltage V2A, and the sampling interval is 1ms. In S22, the number of fluctuations is calculated as follows: when the fluctuation amplitude meets the threshold range, the software accumulates 1 per operation cycle, with a maximum value of 65535; when it does not meet the threshold range, the software decrements 1 per operation cycle, with a minimum value of 0; During implementation, the thresholds V21, V22, V23, dV21 and dV22 are set, the times T21, T22, T23, T24, T25, T26 and T27 are set, and the number of times N21, N22 and N23 are set. These can be set according to different system requirements or hardware characteristics. In this embodiment, the thresholds V21=480V, V22=520V, V23=200V, dV21=15V and dV22=20V are set, the times T21=50ms, T22=50ms, T23=150ms, T24=150ms, T25=50ms, T26=50ms and T27=150ms are set, and the number of times N21=5, N22=5 and N23=10 are set.

[0025] S23: Perform a level 5 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 4 fault and the level 4 process is performed. If the result is true, perform a level 6 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 5 fault and the level 5 process is performed. If the result is true, proceed to S24. In S23, a five-level fault judgment is performed based on the third bus voltage. Specifically, if the result of the fourth-level fault judgment is true, the third bus voltage sent by the DC / DC converter is valid, and any of the five-level fault conditions are met, the result of the five-level fault judgment is true; otherwise, it is false. The five-level fault conditions include: 1) the sampled value of the third bus voltage is greater than the set threshold V31 and less than the set threshold V32, and the retention time exceeds the set time T31; 2) the sampled value of the third bus voltage is greater than the set threshold V32, and the retention time exceeds the set time T32; 3) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV31 and less than the set threshold dV32, and the number of times exceeds the set number N31 within the set time T33; 4) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N32 within the set time T34; 5) the third bus voltage is less than the set threshold V33, and the retention time exceeds the set time T35. The six-level fault judgment based on the third bus voltage is specifically as follows: when the result of the five-level fault judgment is true, the third bus voltage sent by the DC / DC converter is valid, and any of the six-level fault conditions are met, the result of the six-level fault judgment is true, otherwise it is false; the six-level fault conditions include: 1) the sampling value of the third bus voltage is greater than the set threshold V32 and the holding time exceeds the set time T35, 2) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N33 within the set time T36.

[0026] In S23, when identifying whether the third bus voltage sent by the DC / DC converter is valid, it can be identified by using a valid flag sent by the DC / DC converter, whether the CAN signal frame is valid, etc.; The fluctuation amplitude of the third bus voltage is calculated using the following formula: ΔV3=V3A-V3B Wherein, ΔV3 represents the fluctuation amplitude of the third bus voltage, V3A and V3B represent the third bus voltages in two sampling cycles respectively, the sampling time of the third bus voltage V3B is before the third bus voltage V3A, and the sampling interval is 1 ms. In S23, the number of fluctuations is calculated as follows: when the fluctuation amplitude meets the threshold range, the software accumulates 1 per operation cycle, with a maximum value of 65535; when it does not meet the threshold range, the software decrements 1 per operation cycle, with a minimum value of 0; During implementation, the thresholds V31, V32, V33, dV31 and dV32 are set, the times T31, T32, T33, T34, T35, T36 and T37 are set, and the number of times N31, N32 and N33 are set. These can be set according to different system requirements or hardware characteristics. In this embodiment, the thresholds V31=480V, V32=520V, V33=200V, dV31=15V and dV32=20V are set, the times T31=50ms, T32=50ms, T33=150ms, T34=150ms, T35=50ms, T36=50ms and T37=150ms are set, and the number of times N31=5, N32=5 and N33=10 are set.

[0027] S24: Perform a level 7 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 6 fault and level 6 processing is performed. If the result is true, perform an level 8 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 7 fault and level 7 processing is performed. If the result is true, it is judged as a level 8 fault and level 8 processing is performed.

[0028] In S24, the seven-level fault judgment is performed based on the fourth bus voltage. Specifically, if the result of the six-level fault judgment is true, the fourth bus voltage sent by the BMS is valid, and any of the seven-level fault conditions are met, the result of the seven-level fault judgment is true, otherwise it is false. The seven-level fault conditions include: 1) the sampled value of the fourth bus voltage is greater than the set threshold V41 and less than the set threshold V42, and the retention time exceeds the set time T41; 2) the sampled value of the fourth bus voltage is greater than the set threshold V42, and the retention time exceeds the set time T42; 3) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV41 and less than the set threshold dV42, and the number of times exceeds the set number N41 within the set time T43; 4) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N42 within the set time T44; 5) the fourth bus voltage is less than the set threshold V43, and the retention time exceeds the set time T45; The eight-level fault judgment based on the fourth bus voltage is specifically as follows: when the result of the seventh-level fault judgment is true, the fourth bus voltage sent by the BMS is valid, and any of the eight-level fault conditions is met, the result of the eighth-level fault judgment is true, otherwise it is false; the eight-level fault conditions include: 1) the sampling value of the fourth bus voltage is greater than the set threshold V42, and the holding time exceeds the set time T45, 2) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N43 within the set time T46.

[0029] In S24, when identifying whether the fourth bus voltage sent by the BMS is valid, it can be identified by a valid flag bit sent by the BMS, whether the CAN signal frame is valid, etc.; The fluctuation amplitude of the fourth bus voltage is calculated using the following formula: ΔV4=V4A-V4B Wherein, ΔV4 represents the fluctuation amplitude of the fourth bus voltage, V4A and V4B represent the fourth bus voltages in two sampling cycles respectively, the sampling time of the fourth bus voltage V4B is before the fourth bus voltage V4A, and the sampling interval is 1ms. In S24, the number of fluctuations is calculated as follows: when the fluctuation amplitude meets the threshold range, the software accumulates 1 per operation cycle, with a maximum value of 65535; when it does not meet the threshold range, the software decrements 1 per operation cycle, with a minimum value of 0; During implementation, the thresholds V41, V42, V43, dV41 and dV42 are set, the times T41, T42, T43, T44, T45, T46 and T47 are set, and the number of times N41, N42 and N43 are set. They can be set according to different system requirements or hardware characteristics. In this embodiment, the thresholds V41=480V, V42=520V, V43=200V, dV41=15V and dV42=20V are set, the times T41=50ms, T42=50ms, T43=150ms, T44=150ms, T45=50ms, T46=50ms and T47=150ms are set, and the number of times N41=5, N42=5 and N43=10 are set.

[0030] The IPU has a fault flag bit Byte0 corresponding to level 1 fault, level 2 fault, level 3 fault, level 4 fault, level 5 fault, level 6 fault, level 7 fault, and level 8 fault, respectively. The default value is 0. Each level of fault corresponds to a bit in Byte0. When a fault occurs, the corresponding bit in Byte0 is set to 1, and the corresponding processing is performed. At the same time, a fault status record is set for each bus voltage detection. For example, Byte1 is set for the first bus voltage fault. When the first condition of the level 1 fault judgment is met, bit 0 of Byte1 is set to 1; when the second condition is met, bit 1 of Byte1 is set to 1; when the third condition is met, bit 2 of Byte1 is set to 1; when the fourth condition is met, bit 3 of Byte1 is set to 1; and when the fifth condition is met, bit 4 of Byte1 is set to 1. When the first condition of the level 2 fault judgment is met, bit 5 of Byte1 is set to 1; when the second condition is met, bit 6 of Byte1 is set to 1. Similarly, Byte2, Byte3, and Byte4 are set for the other three bus voltage fault status records.

[0031] When the IPU performs primary processing, secondary processing, tertiary processing, quaternary processing, quinary processing, sixth processing, and seventh processing, the IPU maintains normal mode and the output torque of the motor controlled by the IPU decreases from the current value to zero according to the set slope. The corresponding formula is: T= -K n×t+T0 Where T represents the output torque of the motor, K n represents the set slope of the corresponding processing, {n∈Z|1≤x≤7}, t represents the duration of the fault, and T0 represents the output torque of the motor when the corresponding processing is executed.

[0032] When the IPU performs level eight processing, the IPU switches to fault mode. When the motor speed is greater than the set threshold R, the ASC (Active Short Circuit) processing is executed, otherwise the FW (Free Wheeling) processing is executed; ASC is a key safety feature in motor controllers. It works by actively short-circuiting the motor windings. When a potentially dangerous abnormality is detected, such as a drive system failure, uncontrolled acceleration, or other potential safety hazard, ASC activates and takes immediate action. This short-circuit generates a large damping torque in the motor, quickly slowing or stopping it and preventing potential damage. FW processing is an operating mode or state in the motor controller. Its working principle is that when the motor is in FW mode, the inverter's switching elements (such as IGBTs or MOSFETs) will not actively provide current or voltage to the motor, allowing the motor to rotate freely due to inertia or external forces. In this state, the motor no longer operates as a power source, but is similar to an unpowered load, which can be driven to rotate by the vehicle's kinetic energy or other external forces. In some emergency situations or to achieve specific dynamic responses, temporarily allowing the motor to enter FW mode can help avoid potential risks or improve vehicle handling performance.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for diagnosing bus voltage by a motor controller, characterized in that: The diagnostic processing method is based on a monitoring circuit, which includes a busbar and a CAN line. The busbar is electrically connected to a BMS, a DC / DC converter, and an IPU. The BMS and the DC / DC converter are respectively communicatively connected to the IPU via the CAN line. The IPU has a first sampling circuit and a second sampling circuit respectively electrically connected to the busbar. The diagnostic processing method includes the following steps: S1: Obtain bus voltage: The IPU obtains the first bus voltage through the first sampling circuit, obtains the second bus voltage through the second sampling circuit, obtains the third bus voltage sent by the DC / DC converter through the CAN line, and obtains the fourth bus voltage sent by the BMS through the CAN line; S2: Fault judgment and processing: The IPU judges the fault level according to the first bus voltage, the second bus voltage, the third bus voltage and the fourth bus voltage and performs corresponding processing according to the fault level.

2. The method for diagnosing bus voltage by a motor controller according to claim 1, characterized in that: S2 includes the following sub-steps: S21: Performing a primary fault judgment based on the first bus voltage. If the result is false, the bus voltage is judged to be fault-free. If the result is true, performing a secondary fault judgment based on the first bus voltage. If the result is false, it is judged to be a primary fault and primary processing is performed. If the result is true, proceeding to the next step. S22: Performing a level 3 fault judgment based on the second bus voltage. If the result is false, it is judged as a level 2 fault and the level 2 processing is performed. If the result is true, performing a level 4 fault judgment based on the second bus voltage. If the result is false, it is judged as a level 3 fault and the level 3 processing is performed. If the result is true, proceeding to the next step. S23: Perform a level 5 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 4 fault and the level 4 process is performed. If the result is true, perform a level 6 fault judgment based on the third bus voltage. If the result is false, it is judged as a level 5 fault and the level 5 process is performed. If the result is true, proceed to the next step. S24: Perform a level 7 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 6 fault and level 6 processing is performed. If the result is true, perform an level 8 fault judgment based on the fourth bus voltage. If the result is false, it is judged as a level 7 fault and level 7 processing is performed. If the result is true, it is judged as a level 8 fault and level 8 processing is performed.

3. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S21, the first-level fault judgment is performed based on the first bus voltage. Specifically, if the ignition signal validity time exceeds the set time T01, the high voltage on the system exceeds the set time T02, and any first-level fault condition is met, the result of the first-level fault judgment is true, otherwise it is false. The first-level fault conditions include: 1) the first bus voltage is greater than the set threshold V11 and less than the set threshold V12, and the maintenance time exceeds the set time T11; 2) the first bus voltage is greater than the set threshold V12, and the maintenance time exceeds the set time T12; 3) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV11 and less than the set threshold dV12, and the number of times exceeds the set number N11 within the set time T13; 4) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N12 within the set time T14; 5) the first bus voltage is less than the set threshold V13, and the maintenance time exceeds the set time T15; The specific secondary fault judgment based on the first bus voltage is: when any secondary fault condition is met, the result of the secondary fault judgment is true, otherwise it is false; the secondary fault conditions include: 1) the first bus voltage is greater than the set threshold V12, and the maintenance time exceeds the set time T16, 2) the fluctuation amplitude of the first bus voltage is greater than the set threshold dV12, and the number of times exceeds the set number N13 within the set time T17.

4. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S22, the three-level fault judgment is performed based on the second bus voltage. Specifically, when any three-level fault conditions are met, the result of the three-level fault judgment is true, otherwise it is false. The three-level fault conditions include: 1) the second bus voltage is greater than the set threshold V21 and less than the set threshold V22, and the holding time exceeds the set time T21; 2) the second bus voltage is greater than the set threshold V22, and the holding time exceeds the set time T22; 3) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV21 and less than the set threshold dV22, and the number of times exceeds the set number N21 within the set time T23; 4) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N22 within the set time T24; 5) the second bus voltage is less than the set threshold V23, and the holding time exceeds the set time T25; The four-level fault judgment based on the second bus voltage is specifically: when any of the four-level fault conditions is met, the result of the four-level fault judgment is true, otherwise it is false; the four-level fault conditions include: 1) the second bus voltage is greater than the set threshold V22, and the maintenance time exceeds the set time T25, 2) the fluctuation amplitude of the second bus voltage is greater than the set threshold dV22, and the number of times exceeds the set number N23 within the set time T26.

5. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S23, the five-level fault judgment is performed based on the third bus voltage. Specifically, when any of the five-level fault conditions is met, the result of the five-level fault judgment is true, otherwise it is false. The five-level fault conditions include: 1) the third bus voltage is greater than the set threshold V31 and less than the set threshold V32, and the holding time exceeds the set time T31; 2) the third bus voltage is greater than the set threshold V32, and the holding time exceeds the set time T32; 3) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV31 and less than the set threshold dV32, and the number of times exceeds the set number N31 within the set time T33; 4) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N32 within the set time T34; 5) the third bus voltage is less than the set threshold V33, and the holding time exceeds the set time T35; The specific six-level fault judgment based on the third bus voltage is: when any six-level fault conditions are met, the result of the six-level fault judgment is true, otherwise it is false; the six-level fault conditions include: 1) the third bus voltage is greater than the set threshold V32, and the maintenance time exceeds the set time T35, 2) the fluctuation amplitude of the third bus voltage is greater than the set threshold dV32, and the number of times exceeds the set number N33 within the set time T36.

6. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S24, a seven-level fault judgment is performed based on the fourth bus voltage. Specifically, when any of the seven-level fault conditions is met, the result of the seven-level fault judgment is true, otherwise it is false. The seven-level fault conditions include: 1) the fourth bus voltage is greater than the set threshold V41 and less than the set threshold V42, and the maintenance time exceeds the set time T41; 2) the fourth bus voltage is greater than the set threshold V42, and the maintenance time exceeds the set time T42; 3) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV41 and less than the set threshold dV42, and the number of times exceeds the set number N41 within the set time T43; 4) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N42 within the set time T44; 5) the fourth bus voltage is less than the set threshold V43, and the maintenance time exceeds the set time T45; The eight-level fault judgment based on the fourth bus voltage is specifically: when any of the eight-level fault conditions is met, the result of the eight-level fault judgment is true, otherwise it is false; the eight-level fault conditions include: 1) the fourth bus voltage is greater than the set threshold V42, and the maintenance time exceeds the set time T45, 2) the fluctuation amplitude of the fourth bus voltage is greater than the set threshold dV42, and the number of times exceeds the set number N43 within the set time T46.

7. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S2, when the IPU performs the first-level processing, the second-level processing, the third-level processing, the fourth-level processing, the fifth-level processing, the sixth-level processing, and the seventh-level processing, the IPU maintains the normal mode, and the output torque of the motor controlled by the IPU decreases from the current value to zero according to the set slope. The corresponding formula is: T= -K n ×t+T0 Where T represents the output torque of the motor, K n represents the set slope of the corresponding processing, {n∈Z|1≤x≤7}, t represents the duration of the fault, and T0 represents the output torque of the motor when the corresponding processing is executed.

8. The method for diagnosing bus voltage by a motor controller according to claim 2, characterized in that: In S2, when the IPU performs the eight-level processing, the IPU switches to the fault mode. When the motor speed is greater than the set threshold R, the ASC processing is performed, otherwise the FW processing is performed.

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