Vehicle motor insulation fault detection method, motor controller, system, medium and electric vehicle

Abstract

The invention discloses an insulation fault detection method for a vehicle motor, a motor controller, a system, a medium and an electric automobile, and the method comprises the steps: detecting whether the motor has torque output or not under the condition that a power battery and the motor controller are connected; a motor shell of the motor and the vehicle body are electrically common-grounded; if yes, the sum of the three-phase currents of the motor is obtained, and when the sum of the three-phase currents of the motor is larger than a set current threshold value, it is determined that the motor has an insulation fault; wherein the current of each phase of the motor is detected by the corresponding current sensor; if not, an upper bridge arm in any bridge arm circuit connected with the motor is controlled to be in a closed state, the voltage sensor is used for detecting the voltage amplitude of a first pre-charging capacitor in the motor controller, and when the voltage amplitude of the first pre-charging capacitor is larger than a set voltage threshold value, it is determined that the insulation fault exists in the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a method for detecting insulation faults of a vehicle motor, a motor controller, a system, a medium, and an electric vehicle. Background Art

[0002] Electric vehicle motor insulation failure occurs when the insulation layer, due to factors such as aging, damage, and moisture, becomes electrically insulated in areas that should remain insulated. The motor is a core power component in an electric vehicle's high-voltage system, and the industry places high demands on its reliability and safety. Under normal circumstances, good insulation prevents current leakage between the motor's live parts and other components, such as the motor housing and the vehicle body. However, damage to the insulation layer can cause current to leak into areas that should not be conductive, resulting in leakage. This leakage not only affects the motor's normal performance but also poses serious safety risks to the vehicle and its passengers, potentially causing electric shock or even serious accidents such as vehicle fires. Therefore, detection of motor insulation failure is essential.

[0003] Currently, motor insulation fault detection and diagnosis are typically integrated into the BMS (Battery Management System), which cannot promptly capture instantaneous insulation fault information. Once an insulation fault occurs in a motor, but incomplete insulation testing indicates no abnormalities, the motor will continue to operate in a faulty state, potentially causing failure of the vehicle's high-voltage system, leading to burnout (adhesion) of the high-voltage relay S1 or S2, and burnout of the motor control unit, among other serious consequences. This poses a serious threat to the safety of the vehicle and personnel. Summary of the Invention

[0004] In order to solve or partially solve the technical problem that the existing motor insulation fault detection technology cannot detect motor insulation faults in a timely manner, the present invention provides a vehicle motor insulation fault detection method, motor controller, system, medium and electric vehicle. When the motor insulation fails, the motor case is conductive, resulting in current leakage, and the motor coil is connected to the first pre-charge capacitor through the vehicle body to form a large circulation loop, which will cause the first pre-charge capacitor to increase in voltage. Therefore, a motor insulation processor is added to the motor controller, a current sensor is added to the bridge arm line connected to each phase of the motor, and a voltage sensor is added at both ends of the first pre-charge capacitor. By directly collecting the sum of the three-phase currents of the motor and the voltage amplitude of the first pre-charge capacitor, the motor fault is determined in a timely and accurate manner, thereby avoiding operation under the condition of motor failure and causing safety accidents.

[0005] To solve the above technical problems, the first aspect of the present application discloses a kind of insulation fault detection methods of vehicle motor, the motor is connected by motor controller and battery management system management power battery, the motor controller includes the bridge arm line connected with each phase of the motor, the pre-charge branch formed by the first pre-charge capacitor and the second pre-charge capacitor in series, motor insulation processor, current sensor and voltage sensor;Wherein, the pre-charge branch is parallel to the battery management system and the bridge arm line;Ground line is extended between the first pre-charge capacitor and the second pre-charge capacitor and the vehicle body is realized electrical supply ground, the voltage sensor is arranged at the two ends of the first pre-charge capacitor;The bridge arm line connected with each phase of the motor is configured with the current sensor;The current sensor and the voltage sensor are connected with the motor insulation processor respectively;The method comprises:

[0006] In the case where the power battery and the motor controller are connected, whether the motor has torque output is detected;Wherein, the motor shell of the motor and the vehicle body are electrically grounded;

[0007] If yes, the sum of three-phase current of motor is obtained, and when the sum of three-phase current of motor is greater than a set current threshold, it is determined that the motor has insulation fault;Wherein, the current of each phase of the motor is detected by the corresponding current sensor;

[0008] If no, the upper bridge arm in any bridge arm line connected with the motor is controlled to be in closed state, and the voltage amplitude of the first pre-charge capacitor in the motor controller is detected using the voltage sensor, and when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold, it is determined that the motor has insulation fault.

[0009] Optionally, when the sum of three-phase current of motor is greater than a set current threshold, the method further comprises:

[0010] The voltage amplitude of the first pre-charge capacitor in the motor controller is detected using the voltage sensor, and when the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that the motor has insulation fault.

[0011] Optionally, after detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, the method further comprises:

[0012] The change frequency of the first pre-charge capacitor is detected using the voltage sensor;

[0013] When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, and the voltage change frequency of the first pre-charge capacitor exceeds a set change frequency threshold, it is determined that the motor has insulation fault.

[0014] Optionally, controlling an upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and using the voltage sensor to detect a voltage amplitude of a first pre-charge capacitor in the motor controller, and determining that an insulation fault exists in the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold, specifically includes:

[0015] If the voltage amplitude of the first pre-charge capacitor is greater than a first set voltage threshold, it is determined that an insulation fault occurs at a junction point of the three-phase coil windings of the motor;

[0016] If the voltage amplitude of the first pre-charge capacitor is greater than the second set voltage threshold, it is determined that an insulation fault occurs at one end of the single-phase coil winding connected to the upper bridge arm in any bridge arm circuit connected to the motor; wherein the second set voltage threshold is higher than the first set voltage threshold.

[0017] Optionally, controlling an upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and using the voltage sensor to detect a voltage amplitude of a first pre-charge capacitor in the motor controller, and determining that an insulation fault exists in the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold, specifically includes:

[0018] controlling the upper bridge arm connected to the U phase of the motor to be in a closed state, detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, and determining that an insulation fault exists in the U phase of the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold; and / or,

[0019] controlling an upper bridge arm connected to the V phase of the motor to be in a closed state, detecting a voltage amplitude of a first pre-charge capacitor in the motor controller using the voltage sensor, and determining that an insulation fault exists in the V phase of the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold; and / or,

[0020] The upper bridge arm connected to the motor W phase is controlled to be in a closed state, and the voltage amplitude of the first pre-charge capacitor in the motor controller is detected by using the voltage sensor. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor W phase.

[0021] Optionally, after determining that the motor has an insulation fault, the method further includes:

[0022] The fault code is transmitted to the vehicle controller, which controls the alarm.

[0023] A second aspect of the present invention discloses a motor controller, comprising: a bridge arm circuit connected to each phase of the motor, a pre-charge branch formed by a first pre-charge capacitor and a second pre-charge capacitor connected in series, a motor insulation processor, a current sensor, and a voltage sensor; wherein the pre-charge branch is connected in parallel to a battery management system and the bridge arm circuit; a ground wire extends between the first pre-charge capacitor and the second pre-charge capacitor to provide grounding to the vehicle body, and the voltage sensor is provided at both ends of the first pre-charge capacitor; the bridge arm circuit connected to each phase of the motor is equipped with the current sensor; the current sensor and the voltage sensor are respectively connected to the motor insulation processor; the motor insulation processor is used to:

[0024] When the power battery managed by the battery management system and the motor controller are connected, detecting whether the motor has torque output; wherein the motor housing of the motor and the vehicle body realize electrical common grounding;

[0025] If yes, obtain the sum of the three-phase currents of the motor, and when the sum of the three-phase currents of the motor is greater than a set current threshold, determine that the motor has an insulation fault; wherein the current of each phase of the motor is detected by the corresponding current sensor;

[0026] If not, control the upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and use the voltage sensor to detect the voltage amplitude of the first pre-charge capacitor in the motor controller. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor.

[0027] According to a third aspect of the present invention, a computer-readable storage medium is disclosed, on which a computer program is stored. When the program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0028] A fourth aspect of the present invention discloses an insulation fault detection system for a vehicle motor, the system comprising: a motor, a motor controller, and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system;

[0029] The motor controller is used to execute the insulation fault detection method for the vehicle motor described in the first aspect.

[0030] A fifth aspect of the present invention discloses an electric vehicle, comprising a motor, a motor controller, and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system;

[0031] The motor controller is used to execute the vehicle motor insulation fault detection method described in the first aspect. Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0032] The present invention provides a vehicle motor insulation fault detection method, motor controller, system, medium and electric vehicle. When the motor insulation fails, the motor housing becomes conductive, resulting in current leakage. The motor coil is connected to the first pre-charge capacitor through the vehicle body to form a large circulation loop, which will cause the first pre-charge capacitor to increase in voltage. Therefore, a motor insulation processor is added to the motor controller, a current sensor is added to the bridge arm line connected to each phase of the motor, and a voltage sensor is added at both ends of the first pre-charge capacitor. By directly collecting the sum of the three-phase current of the motor and the voltage amplitude of the first pre-charge capacitor, the motor fault is determined in a timely and accurate manner, thereby avoiding operation under the condition of motor failure and causing safety accidents.

[0033] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0035] Figure 1A-1B FIG2 shows an architecture diagram of an insulation fault detection system for a vehicle motor according to an embodiment of the present invention;

[0036] Figure 2 A flow chart of a method for detecting insulation fault of a vehicle motor according to an embodiment of the present invention is shown;

[0037] Figure 3 Shown is an overall implementation logic diagram according to the present invention. DETAILED DESCRIPTION

[0038] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0039] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0040] In a first aspect, an embodiment of the present invention provides a method for detecting insulation faults in a vehicle motor, which is primarily used in a vehicle motor insulation fault detection system. To explain the embodiments of the present invention, the following first introduces an architecture diagram of the vehicle motor insulation fault detection system.

[0041] like Figure 1A-1B As shown, the vehicle motor insulation fault detection system includes: a motor, a motor controller, and a battery management system. The motor is connected to a power battery managed by the motor controller and the battery management system.

[0042] Specifically, the battery management system is connected to the power battery and PDU (Power Distribution Unit). The battery management system is connected to the motor controller via the first and second main relays S1 and S2. A pre-charge relay S3 is connected in series with resistor R1 and then in parallel with the second main relay S2.

[0043] The motor controller includes a bridge arm circuit connected to each phase of the motor, a pre-charge branch formed by a first pre-charge capacitor C1 and a second pre-charge capacitor C2 connected in series, a motor insulation processor, a current sensor A and a voltage sensor VS.

[0044] Among them, the motor controller is provided with three bridge arm circuits for controlling the three-phase motor. Figure 1A-1B In the positional relationship shown in Figure 1, the upper arm is identified as the upper arm, and the lower arm is identified as the lower arm. Therefore, each arm circuit consists of an upper arm and a lower arm, each of which has an IGBT (Insulated Gate Bipolar Transistor). By controlling the on and off of the IGBT switches in each arm, the motor enters a modulation state and normally outputs torque, providing power to the vehicle.

[0045] The three phases of the motor are: U phase, V phase, and W phase, and each phase of the motor is connected between the upper bridge arm and the lower bridge arm in the corresponding bridge arm circuit. Figure 1A-1BThe six bridge arms (IG1 to IG6) connected to the motor are shown. The U phase is connected between the upper bridge arm IG1 and the lower bridge arm IG2, and is connected to the power battery through the upper bridge arm IG1 or the lower bridge arm IG2; the V phase is connected between the upper bridge arm IG3 and the lower bridge arm IG4, and is connected to the power battery through the upper bridge arm IG3 or the lower bridge arm IG4; the W phase is connected between the upper bridge arm IG5 and the lower bridge arm IG6, and is connected to the power battery through the upper bridge arm IG5 or the lower bridge arm IG6. During the specific operation process, the U phase of the motor can be put into a modulation state and output torque by turning on the IGBT switches in the upper bridge arm IG1, the lower bridge arm IG4, and the lower bridge arm IG6; the V phase of the motor can be put into a modulation state and output torque by turning on the IGBT switches in the upper bridge arm IG3, the lower bridge arm IG2, and the lower bridge arm IG6; and the W phase of the motor can be put into a modulation state and output torque by turning on the IGBT switches in the upper bridge arm IG5, the lower bridge arm IG2, and the lower bridge arm IG4.

[0046] The motor housing and the vehicle body share a common electrical ground. For example, the motor housing is connected to the vehicle body through protective grounding, forming a common electrical ground. Protective grounding refers to a concept in the field of electrical safety. By connecting the metal housing of electrical equipment to a grounded object (such as the vehicle body), the vehicle body is used as the grounding reference point for the entire vehicle. This directs potential leakage and static electricity from the motor housing into the vehicle body through a low-impedance path for dissipation. This prevents electric shock accidents caused by human contact with the housing in the event of equipment leakage. It also ensures the potential consistency of the motor and the entire vehicle's electrical system, avoiding interference or safety risks caused by potential differences.

[0047] In addition, the pre-charge branch formed by the first pre-charge capacitor C1 and the second pre-charge capacitor C2 in series is connected in parallel with the battery management system and the bridge arm circuit. Specifically, the two ends of the pre-charge branch formed by the first pre-charge capacitor C1 and the second pre-charge capacitor C2 in series are respectively connected to the first main relay S1 and the second main relay S2, which are used to pre-charge and stabilize the battery management system.

[0048] Optionally, a third pre-charge capacitor C3 is further connected in parallel between the pre-charge branch formed by the first pre-charge capacitor C1 and the second pre-charge capacitor C2 connected in series and the bridge arm circuit.

[0049] Specifically, the pre-charge relay S3 is closed before the second main relay S2 is closed, and the first pre-charge capacitor C1, the second pre-charge capacitor C2, and the third pre-charge capacitor C3 are charged. After the demand is met, the first main relay S1 and the second main relay S2 are closed to turn on the motor controller and the battery management system (that is, the power battery is turned on).

[0050] Furthermore, after the bridge arm circuits are connected in parallel, they are then connected in parallel with the pre-charge branch and the third pre-charge capacitor C3. When the DC power output by the power battery passes through the corresponding bridge arm, voltage fluctuations will occur due to the high-frequency switching of the IGBT and load fluctuations. The pre-charge branch formed by the series connection of the first pre-charge capacitor C1 and the second pre-charge capacitor C2, as well as the third pre-charge capacitor C3, act as filter capacitors, absorbing voltage spikes and filling voltage troughs, making the bus voltage smoother and ensuring the stable operation of devices such as the IGBT.

[0051] In addition, a grounding wire extends between the first pre-charge capacitor C1 and the second pre-charge capacitor C2 and connects to the vehicle body to provide grounding for the electrical equipment. For example, the grounding wire is connected to the vehicle body to form an electrical common ground.

[0052] When the motor insulation fails, the motor housing conducts electricity. Since the ground wires extending between the motor and the first pre-charge capacitor C1 and the second pre-charge capacitor C2 are both connected to the vehicle body for electrical power supply, they conduct electricity and form a circulating current loop (also known as an abnormally conductive loop).

[0053] Furthermore, the motor insulation failure may be caused by an insulation failure at the end where the single-phase coil is connected to the upper bridge arm, or by an insulation failure at the junction of the three-phase coil. For example, when the upper bridge arm IG5 is turned on, two circulating current loops (i.e., abnormal conduction loops) will be generated due to the insulation failures in the above two situations. Figure 1A In the example, the circulating current loop (also known as the abnormal conduction loop) generated when the insulation of the left end of the W phase of the motor (that is, the end where the W phase coil is connected to the upper bridge arm IG5) is abnormal is yellow. Figure 1B In the example, the circulating current loop (also known as the abnormal conductive loop) generated by an insulation abnormality at the junction of the three-phase coil windings (the junction of the right ends of the three phases U, W, and V) is colored red. It is worth noting that the voltage boost caused by the yellow circulating current on the first pre-charge capacitor C1 is more severe than that caused by the red circulating current. In other words, the voltage amplitude caused by the boost on the first pre-charge capacitor C2 due to a single-phase insulation fault is higher than the voltage amplitude caused by the boost on the first pre-charge capacitor C2 due to a three-phase insulation fault.

[0054] Of course, when the upper bridge arm IG1 is turned on, two circulating current loops are generated: one when the insulation abnormality occurs at the left end of the motor's U phase, and the other when the insulation abnormality occurs at the three-phase junction (the right end of the UWV phase). When the upper bridge arm IG3 is turned on, two circulating current loops are also generated: one when the insulation abnormality occurs at the left end of the motor's V phase, and the other when the insulation abnormality occurs at the three-phase junction (the right end of the UWV phase).

[0055] In normal circumstances, the sum of the three-phase current of the motor is at a set current threshold, for example, 2% of the sum of the three current sensors A. When an abnormal fluctuation occurs in a certain phase current, the sum of the three-phase current will exceed the set current threshold due to the abnormal fluctuation of the certain phase current. In addition, when an insulation abnormality occurs at both ends of the coil of the motor, regardless of the cause of the insulation failure, a loop current circuit will be formed through the first pre-charge capacitor C1, causing the voltage of the first pre-charge capacitor C1 to rise. For example, the voltage of the first pre-charge capacitor C1 is normally 50% of the voltage of the power battery, and after an insulation accident occurs in the motor, the voltage will rise to nearly the voltage of the power battery. In addition, the voltage amplitude generated by the voltage rise of the first pre-charge capacitor C2 caused by a single-phase insulation fault is higher than the voltage amplitude generated by the voltage rise of the first pre-charge capacitor C2 caused by a three-phase insulation fault, and the voltage change frequency is also faster than the voltage change frequency of the first pre-charge capacitor C2 caused by a three-phase insulation fault. Therefore, monitoring the amplitude and frequency of the voltage of the first pre-charge capacitor C1 can timely and accurately detect the insulation failure of the motor.

[0056] In view of the above findings, the present application is to timely and accurately detect motor faults, and a voltage sensor VS is arranged at both ends of the first pre-charge capacitor C1. The bridge arm circuit connected to each phase of the motor is provided with a current sensor A. Specifically, each bridge arm circuit includes an upper bridge arm and a lower bridge arm, and the output end of each upper bridge arm is provided with a current sensor A. A motor insulation processor is also provided and connected to the current sensor A and the voltage sensor VS for timely detection of motor faults. It can be seen that the present application directly collects the sum of the three-phase current of the motor and the voltage amplitude of the first pre-charge capacitor C1 to timely and accurately determine the motor fault, thereby avoiding working in the case of motor failure and causing safety accidents.

[0057] In order to illustrate and explain the present application, the following Figure 2 is a flow chart of a method for detecting insulation faults of a vehicle motor, which includes the following steps:

[0058] S201, in the case where the power battery and the motor controller are connected, detecting whether the motor has a torque output.

[0059] Specifically, the first main relay S1 can be normally closed, and when the second main relay S2 is closed, it indicates that the power battery managed by the battery management system and the motor controller are connected.

[0060] When IG1-IG6 in the motor controller are sequentially closed according to the three-phase inverter logic, the motor three-phase coil winding will be driven to generate a rotating magnetic field, driving the motor rotor to rotate and output torque. In actual detection, the detection can be performed by detecting whether the motor controller outputs torque control instructions (for example, whether the PWM signal for driving the IGBT is output), or detecting the rotor speed detected by the motor speed sensor, or directly measuring the torque sensor at the motor load end.

[0061] S202, if yes, obtaining the sum of the motor three-phase currents, and determining that the motor has insulation failure when the sum of the motor three-phase currents is greater than the set current threshold.

[0062] Wherein, if the motor has torque output, it indicates that the motor is in working state. The sum of the motor three-phase currents is actually the sum of the currents of the U phase, V phase and W phase of the motor. The currents of each phase of the motor are detected by the corresponding current sensor A.

[0063] In the specific implementation process, the currents of each phase of the motor are detected by the current sensor A, including: the U phase current A m1 of the motor, the V phase current A m2 of the motor, and the W phase current A m3 of the motor. The currents of each phase of the motor are added to obtain the sum of the motor three-phase currents. Further, it is judged whether the sum of the motor three-phase currents is greater than the set current threshold. Wherein, the set current threshold is the first percentage of the sum of the ranges of the three current sensors A, for example, 2% of the sum of the ranges of the three current sensors A, but not limited to. If yes, it is determined that the motor has insulation failure.

[0064] For example, it is judged whether |A m1 +A m2 +A m3 | is greater than 3A m量 × 2%, if less, it indicates that the motor has no insulation failure. If greater, it can be determined that the motor has insulation failure. Wherein, A m量 represents the range of the current sensor A.

[0065] Further, in order to improve the accuracy of the motor insulation failure detection, after judging whether the sum of the motor three-phase currents is greater than the set current threshold, the voltage amplitude of the first pre-charge capacitor C1 in the motor controller is detected by the voltage sensor VS, and when the voltage amplitude of the first pre-charge capacitor C1 is greater than the set voltage threshold, it is determined that the motor has insulation failure. Wherein, the set voltage threshold V 设 is 60% of the power voltage, but not limited to. This embodiment jointly judges the motor insulation failure by combining the current and voltage amplitude. For example, if |A m1 +A m2 +A m3 | > 3Am量 × 2%, and the voltage amplitude of the first pre-charge capacitor C1 is V m1 >V 设 ×60%, it can be determined that there is an insulation fault in the motor.

[0066] Furthermore, after using the voltage sensor VS to detect the voltage amplitude of the first pre-charge capacitor C1 in the motor controller, the voltage sensor VS is used to detect the change frequency of the first pre-charge capacitor C1; when the voltage amplitude of the first pre-charge capacitor C1 is greater than the set voltage threshold, and the voltage change frequency of the first pre-charge capacitor C1 exceeds the set change frequency threshold, it is determined that the motor has an insulation fault. The change frequency threshold is any value between 0.8 times and 1 times the IGBT switching frequency. This embodiment determines the motor insulation fault by combining the current, voltage amplitude and voltage frequency. For example, the insulation fault of the motor is detected by the current sensor VS. m1 +A m2 +A m3 |>3A m量 × 2%, and the voltage amplitude of the first pre-charge capacitor C1 is V m1 >V 设 ×60%, and the voltage variation frequency of the first pre-charge capacitor C1 is greater than 0.8 times the IGBT switching frequency, it is determined that an insulation fault exists in the motor.

[0067] By directly collecting the sum of the three-phase currents of the motor and the voltage amplitude of the first pre-charge capacitor C1 and designing multiple judgment methods, the insulation fault of the motor can be judged promptly and accurately.

[0068] S203, if not, control the upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and use the voltage sensor to detect the voltage amplitude of the first pre-charge capacitor in the motor controller. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor.

[0069] If the motor has no torque output, it's not operating. In this case, upper bridge arms IG1, IG3, and IG5 are controlled to conduct, and the motor insulation fault is determined based on the voltage amplitude and / or frequency of C2. Of course, when each of these upper bridge arms is conducting, the other bridge arms are all off.

[0070] Specifically, the set voltage threshold includes: a first set voltage threshold and a second set voltage threshold, wherein the second set voltage threshold is higher than the first set voltage threshold.

[0071] Since the voltage rise phenomenon of the first pre-charge capacitor C1 caused by a three-phase insulation fault and a single-phase insulation fault is different under the same insulation abnormality level, it is possible to accurately determine whether it is a three-phase insulation fault or a single-phase insulation fault according to different set voltage thresholds.

[0072] During the specific implementation process, if the voltage amplitude of the first pre-charge capacitor C1 is greater than the first set voltage threshold, it is determined that an insulation fault occurs at the junction of the three-phase coil winding of the motor; if the voltage amplitude of the first pre-charge capacitor C1 is greater than the second set voltage threshold, it is determined that an insulation fault occurs at one end of the single-phase coil winding connected to the upper bridge arm in any bridge arm circuit connected to the motor.

[0073] In an optional implementation, the voltage change frequency of the first pre-charge capacitor C1 can be combined to further accurately determine whether it is a three-phase insulation fault or a single-phase insulation fault.

[0074] In a specific implementation, if the voltage variation frequency of the first pre-charge capacitor C1 is greater than a first predetermined variation frequency threshold, an insulation fault is determined to exist at the junction of the three-phase coil windings of the motor. If the voltage variation frequency of the first pre-charge capacitor C1 is greater than a second predetermined variation frequency threshold, an insulation fault is determined to exist at one end of the single-phase coil winding connected to the upper bridge arm of any bridge arm circuit connected to the motor. The second predetermined variation frequency threshold is higher than the first predetermined variation frequency threshold.

[0075] Of course, the voltage variation frequency and the voltage amplitude can be used in combination.

[0076] The following introduces the U phase, V phase, and W phase of the motor respectively. The three can be executed in sequence, individually, or in pairs.

[0077] The upper bridge arm IG1 connected to the motor's U phase is controlled to be in a closed state, and the other bridge arms are controlled to be in an open state. The voltage amplitude of the first pre-charge capacitor C1 in the motor controller is detected using a voltage sensor VS. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a set voltage threshold, an insulation fault is determined to exist in the motor's U phase. Furthermore, when the voltage amplitude of the first pre-charge capacitor C1 is greater than a first set voltage threshold, an insulation fault is determined to exist at the end of the motor's U phase connected to the upper bridge arm IG1. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a second set voltage threshold, an insulation fault is determined to exist at the junction of the motor's three-phase coil windings.

[0078] The upper bridge arm IG3 connected to the motor's V phase is controlled to be in a closed state, and the other bridge arms are controlled to be in an open state. The voltage amplitude of the first pre-charge capacitor C1 in the motor controller is detected using a voltage sensor VS. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a set voltage threshold, an insulation fault is determined to exist in the motor's V phase. Furthermore, when the voltage amplitude of the first pre-charge capacitor C1 is greater than a first set voltage threshold, an insulation fault is determined to exist at the end of the motor's V phase connected to the upper bridge arm IG3. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a second set voltage threshold, an insulation fault is determined to exist at the junction of the motor's three-phase coil windings.

[0079] The upper bridge arm IG5 connected to the motor W phase is controlled to be in a closed state, and the other bridge arms are controlled to be in an open state. The voltage amplitude of the first pre-charge capacitor C1 in the motor controller is detected using a voltage sensor VS. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a set voltage threshold, an insulation fault is determined to exist in the motor's W phase. Furthermore, when the voltage amplitude of the first pre-charge capacitor C1 is greater than a first set voltage threshold, an insulation fault is determined to exist at the end of the motor's W phase connected to the upper bridge arm IG5. When the voltage amplitude of the first pre-charge capacitor C1 is greater than a second set voltage threshold, an insulation fault is determined to exist at the junction of the motor's three-phase coil windings.

[0080] In an optional embodiment, after determining that the motor has an insulation fault, the fault code is transmitted to the vehicle controller, and the vehicle controller controls an alarm, such as an alarm requiring immediate vehicle maintenance.

[0081] To further illustrate and explain the present invention, see Figure 3 , is the overall implementation logic diagram of the present invention.

[0082] S301, determining whether the motor controller is connected to the power battery, that is, whether the second main relay S2 is closed.

[0083] If yes, execute S302 to determine whether the motor has torque output, that is, whether the motor is in working state.

[0084] If yes, it means the motor is in working state, then the sum of current and C2 voltage amplitude and frequency are used to determine whether |Am1+Am2+Am2| is greater than 3A. m量 ×2%.

[0085] If it is less than, the motor has no insulation abnormality problem and goes to S301.

[0086] If it is greater, execute S304 and read the voltage amplitude V of the first pre-charge capacitor C1. m1 .

[0087] S305, determine the voltage amplitude V m1 (and / or frequency) is greater than the corresponding threshold. If not, go to S301. If yes, the motor has insulation fault. Further, V m1 The threshold is determined by the voltage amplitude (normally 50% of the power battery voltage; if motor insulation fault occurs, the voltage will rise to nearly the power battery voltage) and the voltage change frequency (the frequency threshold is set to any value between 0.8 and 1 times the IGBT switching frequency). If the protection threshold is exceeded, the motor controller exits torque mode and reports a motor insulation fault to the vehicle controller, requesting immediate vehicle repair.

[0088] If the motor is not in operation, execute S306 to control the upper bridge arm IG1 to be turned on. S307 to determine the voltage amplitude V of the first pre-charge capacitor C1. m1 (and / or the frequency of change) is greater than a set voltage threshold, for example, 60% of the power battery voltage.

[0089] In the judgment process, if the voltage amplitude V m1 If the voltage exceeds the set voltage threshold, it indicates a motor insulation fault. The specific determination of whether it is a single-phase or three-phase insulation fault can be found in the previous description and will not be repeated here. Furthermore, the motor controller exits torque mode and reports a motor insulation fault to the vehicle controller, requesting immediate repair.

[0090] If the voltage amplitude V m1 If the voltage of the first pre-charge capacitor C1 is less than or equal to the set voltage threshold, execute S308 to control the upper bridge arm IG3 to be turned on. S309 determines the voltage amplitude V m1 (and / or the frequency of change) is greater than a set voltage threshold, for example, 70% of the power battery voltage.

[0091] In the judgment process, if the voltage amplitude V m1 If the voltage exceeds the set voltage threshold, it indicates a motor insulation fault. The specific determination of whether it is a single-phase or three-phase insulation fault can be found in the previous description and will not be repeated here. Furthermore, the motor controller exits torque mode and reports a motor insulation fault to the vehicle controller, requesting immediate repair.

[0092] If the voltage amplitude V m1 is less than or equal to the set voltage threshold, execute S310,

[0093] Control the upper bridge arm IG5 to be turned on. S311, determine the voltage amplitude V of the first pre-charge capacitor C1 m1 (and / or change frequency) is greater than the set voltage threshold.

[0094] In the judgment process, if the voltage amplitude V m1 If the voltage exceeds the set voltage threshold, it indicates a motor insulation fault. The specific determination of whether it is a single-phase or three-phase insulation fault can be found in the previous description and will not be repeated here. Furthermore, the motor controller exits torque mode and reports a motor insulation fault to the vehicle controller, requesting immediate repair.

[0095] In the second aspect, based on the same inventive concept as the vehicle motor insulation fault detection method provided in the embodiment of the first aspect, the embodiment of the present invention further provides a motor controller, which can refer to Figure 1A-1B The architecture of the motor controller in .

[0096] The motor controller includes: a bridge arm circuit connected to each phase of the motor, a pre-charge branch formed by a first pre-charge capacitor C1 and a second pre-charge capacitor C2 connected in series, a motor insulation processor, a current sensor A, and a voltage sensor VS; wherein the pre-charge branch is connected in parallel with the battery management system and the bridge arm circuit; a grounding wire extends between the first pre-charge capacitor C1 and the second pre-charge capacitor C2 to provide grounding for the electrical equipment, and the voltage sensor VS is arranged at both ends of the first pre-charge capacitor C1; the bridge arm circuit connected to each phase of the motor is equipped with the current sensor A; the current sensor A and the voltage sensor VS are respectively connected to the motor insulation processor; the motor insulation processor is used to:

[0097] When the power battery managed by the battery management system and the motor controller are connected, it is detected whether the motor has torque output; wherein the motor housing of the motor and the vehicle body realize electrical common grounding.

[0098] If yes, obtain the sum of the three-phase currents of the motor, and when the sum of the three-phase currents of the motor is greater than a set current threshold, determine that the motor has an insulation fault; wherein the current of each phase of the motor is detected by the corresponding current sensor A;

[0099] If not, control the upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and use the voltage sensor VS to detect the voltage amplitude of the first pre-charge capacitor C1 in the motor controller. When the voltage amplitude of the first pre-charge capacitor C1 is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor.

[0100] It should be noted that the motor controller provided in the embodiment of the present invention, the specific method of performing operations has been described in detail in the method embodiment provided in the above first aspect. The specific implementation process can refer to the method embodiment provided in the above first aspect, and will not be elaborated here.

[0101] In the third aspect, based on the same inventive concept as the vehicle motor insulation fault detection method provided in the aforementioned first aspect embodiment, an embodiment of the present invention further discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the aforementioned first aspect.

[0102] In a fourth aspect, based on the same inventive concept as the vehicle motor insulation fault detection method provided in the embodiment of the first aspect, the embodiment of the present invention further discloses a vehicle motor insulation fault detection system, the schematic diagram of the system is shown in FIG. Figure 1A-1B , comprising: a motor, a motor controller and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system;

[0103] The motor controller is used to execute the insulation fault detection method for a vehicle motor as described in the first aspect.

[0104] In the fifth aspect, based on the same inventive concept as the insulation fault detection method for a vehicle motor provided in the embodiment of the first aspect, an embodiment of the present invention also discloses an electric vehicle, comprising a motor, a motor controller and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system; the motor controller is used to execute the insulation fault detection method for a vehicle motor as described in the first aspect.

[0105] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0106] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for detecting insulation fault of a vehicle motor, characterized in that: The motor is connected to a power battery managed by a motor controller and a battery management system. The motor controller includes a bridge arm circuit connected to each phase of the motor, a pre-charge branch formed by a first pre-charge capacitor and a second pre-charge capacitor connected in series, a motor insulation processor, a current sensor, and a voltage sensor. The pre-charge branch is connected in parallel to the battery management system and the bridge arm circuit. A grounding wire extends between the first pre-charge capacitor and the second pre-charge capacitor to provide grounding to the vehicle body. The voltage sensor is provided at both ends of the first pre-charge capacitor. The bridge arm circuits connected to each phase of the motor are each equipped with a current sensor. The current sensor and the voltage sensor are respectively connected to the motor insulation processor. The method includes: When the power battery and the motor controller are connected, detecting whether the motor has torque output; wherein the motor housing of the motor and the vehicle body realize electrical common grounding; If yes, obtain the sum of the three-phase currents of the motor, and when the sum of the three-phase currents of the motor is greater than a set current threshold, determine that the motor has an insulation fault; wherein the current of each phase of the motor is detected by the corresponding current sensor; If not, control the upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and use the voltage sensor to detect the voltage amplitude of the first pre-charge capacitor in the motor controller. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor.

2. The method according to claim 1, wherein When the sum of the three-phase currents of the motor is greater than a set current threshold, the method further includes: The voltage sensor is used to detect the voltage amplitude of the first pre-charge capacitor in the motor controller. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that an insulation fault exists in the motor.

3. The method according to claim 2, wherein After detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, the method further includes: Detecting a frequency change of the first pre-charge capacitor using the voltage sensor; When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, and the voltage change frequency of the first pre-charge capacitor exceeds the set change frequency threshold, it is determined that the motor has an insulation fault.

4. The method according to claim 1, wherein The controlling of the upper bridge arm in any bridge arm circuit connected to the motor is in a closed state, and detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, and determining that the motor has an insulation fault when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold, specifically includes: If the voltage amplitude of the first pre-charge capacitor is greater than a first set voltage threshold, it is determined that an insulation fault occurs at a junction point of the three-phase coil windings of the motor; If the voltage amplitude of the first pre-charge capacitor is greater than the second set voltage threshold, it is determined that an insulation fault occurs at one end of the single-phase coil winding connected to the upper bridge arm in any bridge arm circuit connected to the motor; wherein the second set voltage threshold is higher than the first set voltage threshold.

5. The method according to claim 1 or 4, wherein: The controlling of the upper bridge arm in any bridge arm circuit connected to the motor is in a closed state, and detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, and determining that the motor has an insulation fault when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold, specifically includes: controlling the upper bridge arm connected to the U phase of the motor to be in a closed state, detecting the voltage amplitude of the first pre-charge capacitor in the motor controller using the voltage sensor, and determining that an insulation fault exists in the U phase of the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold; and / or, controlling an upper bridge arm connected to the V phase of the motor to be in a closed state, detecting a voltage amplitude of a first pre-charge capacitor in the motor controller using the voltage sensor, and determining that an insulation fault exists in the V phase of the motor when the voltage amplitude of the first pre-charge capacitor is greater than a set voltage threshold; and / or, The upper bridge arm connected to the motor W phase is controlled to be in a closed state, and the voltage amplitude of the first pre-charge capacitor in the motor controller is detected by using the voltage sensor. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor W phase.

6. The method according to claim 1, wherein After determining that the motor has an insulation fault, the method further includes: The fault code is transmitted to the vehicle controller, which controls the alarm.

7. A motor controller, characterized in that: The motor controller includes: a bridge arm circuit connected to each phase of the motor, a pre-charge branch formed by a first pre-charge capacitor and a second pre-charge capacitor connected in series, a motor insulation processor, a current sensor, and a voltage sensor; wherein the pre-charge branch is connected in parallel to the battery management system and the bridge arm circuit; a ground wire extends between the first pre-charge capacitor and the second pre-charge capacitor to connect to the vehicle body to realize electrical grounding, and the voltage sensor is arranged at both ends of the first pre-charge capacitor; the bridge arm circuit connected to each phase of the motor is equipped with the current sensor; the current sensor and the voltage sensor are respectively connected to the motor insulation processor; the motor insulation processor is used to: When the power battery managed by the battery management system and the motor controller are connected, detecting whether the motor has torque output; wherein the motor housing of the motor and the vehicle body realize electrical common grounding; If yes, obtain the sum of the three-phase currents of the motor, and when the sum of the three-phase currents of the motor is greater than a set current threshold, determine that the motor has an insulation fault; wherein the current of each phase of the motor is detected by the corresponding current sensor; If not, control the upper bridge arm in any bridge arm circuit connected to the motor to be in a closed state, and use the voltage sensor to detect the voltage amplitude of the first pre-charge capacitor in the motor controller. When the voltage amplitude of the first pre-charge capacitor is greater than the set voltage threshold, it is determined that there is an insulation fault in the motor.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A vehicle motor insulation fault detection system, characterized in that: The system includes: a motor, a motor controller and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system; The motor controller is used to execute the insulation fault detection method for a vehicle motor according to any one of claims 1 to 6.

10. An electric vehicle, characterized in that: It includes a motor, a motor controller and a battery management system; the motor is connected to a power battery managed by the motor controller and the battery management system; The motor controller is used to execute the insulation fault detection method for a vehicle motor according to any one of claims 1 to 6.

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