Fault detection method and apparatus and vehicle

Abstract

Embodiments of the present disclosure provide a fault detection method and device and a vehicle. The fault detection method comprises: acquiring current sensing information, the current sensing information representing a multi-phase current flowing through a multi-phase insulated conductor, the multi-phase insulated conductor being connected between a motor driving device and a motor; determining an actual value of a to-be-controlled electrical quantity of the motor based on the acquired current sensing information; and generating an indication signal that the multi-phase insulated conductor has a first type of fault based on a difference between the determined actual value and an expected value of the to-be-controlled electrical quantity. Through the scheme of the present disclosure, the fault condition of the multi-phase insulated conductor can be monitored in a fast, simple and low-cost manner.

Description

Technical Field

[0001] Embodiments of this disclosure relate to the field of power fault detection technology, and more specifically, to fault detection methods and equipment, as well as vehicles including fault detection equipment. Background Technology

[0002] Electric vehicles typically use an onboard motor to provide various forms of power, and utilize motor drive devices such as inverters to power and drive the motor. Insulated wires or wiring harnesses connect the motor drive device and the motor to transfer high-voltage power from the motor drive device to the motor.

[0003] Insulated wires or harnesses may wear down or detach during prolonged vehicle operation. This wear or detachment can affect the normal operation of the vehicle and its motor, and even lead to safety hazards. For example, worn insulated wires or harnesses may come into contact with the vehicle's body due to vibrations during driving. This reduces the insulation resistance between the core of the high-voltage insulated wire or harness and ground, potentially causing high-voltage current leakage to the vehicle body and ground. This can lead to short-circuit failure of the inverter's insulation, damaging the on-board motor and its drive control equipment, and endangering personal safety. Currently, there is a lack of simple and efficient methods to monitor faults in insulated wires or harnesses. Summary of the Invention

[0004] Based on the above-mentioned problems, and according to the example embodiments of the present disclosure, a fault detection method, a fault detection device, an apparatus for fault detection, and a vehicle are provided.

[0005] In a first aspect of this disclosure, a fault detection method is provided, comprising: acquiring current sensing information, the current sensing information representing a multiphase current flowing through a multiphase insulated conductor connected between a motor drive and a motor; determining an actual value of a controllable electrical quantity of the motor based on the acquired current sensing information; and generating an indication signal indicating that a first type of fault has occurred in the multiphase insulated conductor based on the difference between the determined actual value and the expected value of the controllable electrical quantity.

[0006] In some embodiments of this disclosure, the electrical quantity to be controlled includes at least one of the following: direct-axis voltage, quadrature-axis voltage, direct-axis current, and quadrature-axis current of the motor.

[0007] In some embodiments of this disclosure, the fault detection method further includes: determining the sum of multiphase currents based on the acquired current sensing information; incrementing a count value in response to the sum of multiphase currents exceeding a current threshold; and generating an indication signal indicating that a second type of fault has occurred in the multiphase insulated conductor in response to the count value increasing by more than the threshold within a predetermined time period.

[0008] In some embodiments of this disclosure, a first type of fault includes at least one of the following: continuous short circuits in multiphase insulated conductors and continuous open circuits in multiphase insulated conductors; and a second type of fault includes at least one of the following: continuous short circuits in multiphase insulated conductors, multiple discontinuous short circuits in multiphase insulated conductors, continuous open circuits in some phases of multiphase insulated conductors, and multiple discontinuous open circuits in some phases of multiphase insulated conductors.

[0009] In some embodiments of this disclosure, the fault detection method further includes controlling the motor drive device based on an indication signal.

[0010] In some embodiments of this disclosure, generating an indication signal for a first type of fault in a multiphase insulated conductor based on the difference between the actual and expected values ​​of the determined electrical quantities to be controlled includes: generating the indication signal based on at least one of the following: the difference between the determined direct-axis voltage and the expected direct-axis voltage exceeds a first threshold; the difference between the determined quadrature-axis voltage and the expected quadrature-axis voltage exceeds a second threshold; the difference between the determined direct-axis current and the expected direct-axis current exceeds a third threshold; the difference between the determined quadrature-axis current and the expected quadrature-axis current exceeds a fourth threshold; determining a total voltage difference based on the difference between the determined direct-axis voltage and the expected direct-axis voltage and the difference between the determined quadrature-axis voltage and the expected quadrature-axis voltage, and the total voltage difference exceeds a fifth threshold; and determining a total current difference based on the difference between the determined direct-axis current and the expected direct-axis current and the difference between the determined quadrature-axis current and the expected quadrature-axis current, and the total current difference exceeds a sixth threshold.

[0011] In some embodiments of this disclosure, the total voltage difference includes the Euclidean norm of the difference between the determined direct-axis voltage and the desired direct-axis voltage and the difference between the determined quadrature-axis voltage and the desired quadrature-axis voltage, and wherein the total current difference includes the Euclidean norm of the difference between the determined direct-axis current and the desired direct-axis current and the difference between the determined quadrature-axis current and the desired quadrature-axis current.

[0012] In a second aspect of this disclosure, a fault detection method is provided, comprising: acquiring current sensing information, the current sensing information representing multiphase current flowing through a multiphase insulated conductor connected between a motor drive and a motor; determining the sum of the multiphase currents based on the acquired current sensing information; incrementing a count value in response to the sum of the multiphase currents exceeding a current threshold; and generating an indication signal indicating that a second type of fault has occurred in the multiphase insulated conductor in response to the count value increasing by more than the threshold over a predetermined time period.

[0013] In some embodiments of this disclosure, the second type of fault includes at least one of the following: continuous short circuits in multiphase insulated conductors, multiple discontinuous short circuits in multiphase insulated conductors, continuous open circuits in some phases of multiphase insulated conductors, and multiple discontinuous open circuits in some phases of multiphase insulated conductors.

[0014] In some embodiments of this disclosure, the fault detection method further includes controlling the motor drive device based on an indication signal.

[0015] In a third aspect of this disclosure, an apparatus for fault detection is provided, comprising: an acquisition unit configured to acquire current sensing information representing a multiphase current flowing through a multiphase insulated conductor connected between a motor drive and a motor; a determination unit configured to determine an actual value of a controllable electrical quantity of the motor based on the acquired current sensing information; and a generation unit configured to generate an indication signal indicating that a first type of fault has occurred in the multiphase insulated conductor based on the difference between the determined actual value and a desired value of the controllable electrical quantity.

[0016] In a fourth aspect of this disclosure, an apparatus for fault detection is provided, comprising: an acquisition unit configured to acquire current sensing information representing multiphase current flowing through a multiphase insulated conductor connected between a motor drive and a motor; a determination unit configured to determine the sum of the multiphase currents based on the acquired current sensing information; a counting unit configured to increment a count value in response to the sum of the multiphase currents exceeding a current threshold; and a generation unit configured to generate an indication signal indicating a second type of fault in the multiphase insulated conductor in response to the count increment exceeding the threshold within a predetermined time period.

[0017] In a fifth aspect of this disclosure, a fault detection device is provided, which is adapted to be coupled to a motor and a multiphase insulated wire connected between a motor drive and the motor, and the fault detection device is configured to perform a fault detection method according to the first and second aspects.

[0018] In a sixth aspect of this disclosure, a vehicle is provided, comprising: an electric motor drive, an electric motor, and a multiphase insulated wire connecting the electric motor drive and the electric motor; and a fault detection device according to the fifth aspect.

[0019] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0020] The above and other features, advantages, and aspects of the various embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0021] Figure 1 A schematic block diagram of an electrical system according to an embodiment of the present disclosure is shown.

[0022] Figure 2 A schematic circuit diagram of a portion of the circuitry of an electrical system according to an embodiment of the present disclosure is shown.

[0023] Figure 3A and Figure 3B A schematic diagram of a fault scenario for a multiphase insulated conductor according to an embodiment of the present disclosure is shown.

[0024] Figure 4 A schematic flowchart of a fault detection method according to an embodiment of the present disclosure is shown.

[0025] Figure 5 An exemplary internal block diagram of a fault detection device implementing a fault detection method according to an embodiment of the present disclosure is shown.

[0026] Figure 6 A schematic flowchart of a fault detection method according to another embodiment of the present disclosure is shown.

[0027] Figure 7 An exemplary internal block diagram of a fault detection device implementing a fault detection method according to another embodiment of the present disclosure is shown.

[0028] Figure 8 A schematic waveform diagram of the multiphase current and the sum of the multiphase currents is shown in the case of a short-circuit fault in a multiphase insulated conductor according to an embodiment of the present disclosure.

[0029] Figure 9 A schematic block diagram of an apparatus for fault detection according to an embodiment of the present disclosure is shown.

[0030] Figure 10 A schematic block diagram of an apparatus for fault detection according to another embodiment of the present disclosure is shown. Detailed Implementation

[0031] The embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0032] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0033] As mentioned earlier, the insulated wires connecting the vehicle's motor drive unit and the motor may wear out or detach, leading to short circuits or open circuits. This can severely impact vehicle operation and even cause equipment damage and safety accidents. Some solutions utilize high-frequency current sensors to collect the current in the insulated wires and calculate the center frequency and resonant amplitude, thereby monitoring insulation faults. However, this approach requires additional high-frequency current sensors to measure the current, increasing costs. Other solutions monitor insulation resistance through the higher-level vehicle system. However, this approach only monitors the insulation of the entire vehicle and cannot monitor the insulation of individual components or identify the specific component causing the insulation failure. Furthermore, current monitoring methods are time-consuming, resulting in poor timeliness of fault detection.

[0034] This disclosure provides an improved fault detection method. In embodiments of this disclosure, the actual value of the controllable electrical quantity of the motor can be determined based on current sensing information, and the degree of deviation between the actual value and the expected value can be judged. This allows for the determination of whether a fault, such as wire detachment or insulation failure, has occurred in the multiphase insulated conductor connected between the motor drive device and the motor. In this way, the fault condition of the multiphase insulated conductor can be effectively monitored quickly, simply, and at low cost. Furthermore, in embodiments of this disclosure, the sum of the multiphase currents can also be monitored, and it can be determined whether the sum of the multiphase currents exceeds a threshold too many times within a predetermined time period, thereby determining whether a fault, such as insulation failure, has occurred in the multiphase insulated conductor. In some embodiments of this disclosure, the above two fault detection schemes can be combined for dual detection and verification of faults, and can complementaryly detect multiphase insulated conductor faults, thereby ensuring the accuracy and comprehensiveness of the detection.

[0035] Figure 1 A schematic block diagram of an electrical system 10 according to an embodiment of the present disclosure is shown. Figure 1 As shown, the electrical system 10 includes a power source 100, a motor drive 200, a motor 300, a multiphase insulated conductor 400, and a current sensing device 410. The electrical system 10 can be located within a vehicle to power the vehicle. However, it is understood that the electrical system 10 can also be applied to other scenarios outside of a vehicle. As an example, the power source 100 can be a battery pack or any other type of power source, and the motor drive 200 can include power conversion circuitry such as an inverter to convert the voltage and / or current from the power source 100 into the voltage and / or current required by the motor 300. The multiphase insulated conductor 400 connects the motor drive 200 and the motor 300 to enable power transfer from the motor drive 200 to the motor 300, and the current sensing device 410 can sense the current flowing through the multiphase insulated conductor 400. As an example, the multiphase insulated conductor 400 can include a core formed of a conductor or conductive material, and an insulating layer formed of insulating material surrounding the core. Multiphase insulated conductors 400 can prevent current leakage and short circuits while transmitting electrical energy and prevent other components and personnel from coming into contact with the conductor.

[0036] Electrical system 10 also includes control device 500 and fault detection device 600. Control device 500 controls motor drive unit 200 to drive and control motor 300. For example, control device 500 can control the operation of the inverter in motor drive unit 200 based on sensing signals from motor 300, current sensing device 410, and other components. Fault detection device 600 can detect faults that may occur in multiphase insulated conductor 400, such as short circuits or open circuits, based on sensing information from current sensing device 410. Control device 500 and fault detection device 600 can be implemented in various ways. For example, control device 500 and fault detection device 600 can be implemented as a controller with computing and processing capabilities, as a circuit of analog and / or digital circuits, or as a combination of the above.

[0037] Figure 2A schematic circuit diagram of a portion of the circuitry of an electrical system 10 according to an embodiment of the present disclosure is shown. As an example, the motor drive 200 is a three-phase three-level inverter, the multiphase insulated conductor 400 is a three-phase insulated conductor, and the motor 300 is a three-phase AC motor. The three-phase three-level inverter includes capacitors C1 and C2 connected across the DC bus, an A-phase bridge arm, a B-phase bridge arm, and a C-phase bridge arm. The A-phase bridge arm includes switching devices Sa1, Sa2, Sa3, and Sa4, and diodes D1 and D2; the B-phase bridge arm includes Sb1, Sb2, Sb3, and Sb4, and diodes D3 and D4; and the C-phase bridge arm includes Sc1, Sc2, Sc3, and Sc4, and diodes D5 and D6. The multiphase insulated conductor 410, as a three-phase insulated conductor, is connected at one end to node A of the A-phase bridge arm, node B of the B-phase bridge arm, and node C of the C-phase bridge arm, respectively, and at its other end to the three-phase stator windings of the motor 300, respectively. The fault detection device 600 can acquire current sensing information indicating the three-phase current on the multi-phase insulated conductor 410 from the current sensing device 410, and can also acquire sensing information such as motor speed from the motor 300. The fault detection device 600 can generate an indication signal based on the sensing results and provide it to the control device 600. Therefore, the control device 600 can control the motor drive device 200 according to the indication signal, for example, controlling the motor drive device 200 to stop operation when a short-circuit fault is detected. Although Figure 1 and Figure 2 The control device 500 and the fault detection device 600 are two independent devices, but the functions of the fault detection device 600 can also be integrated into the control device 500 to form a single device. This disclosure does not limit this.

[0038] Figure 3A and Figure 3B A schematic diagram illustrating a fault scenario of a multiphase insulated conductor 400 according to an embodiment of the present disclosure is shown. Figure 3A As shown, in the event of insulation damage to the multiphase insulated conductor 400, one or more phases of the multiphase insulated conductor 400 may experience a short circuit to ground. For example, due to vibrations during vehicle operation, the worn inner core of the insulated conductor 400 may approach or contact the vehicle's housing, causing intermittent or discontinuous multiple short circuits to ground. Additionally, as... Figure 3B As shown, one or more phases of the multiphase insulated conductor 400 may be broken due to damage, for example, due to vehicle vibration, one or more phases of the insulated conductor 400 may detach from the connection terminal of the motor 300.

[0039] Figure 4 A schematic flowchart of a fault detection method 4000 according to an embodiment of the present disclosure is shown. Method 4000 can be implemented in... Figure 1 and Figure 2This is implemented in the scenario described above and executed by the fault detection device 600. Alternatively, method 4000 can also be executed by a control device 500 that integrates the functionality of the fault detection device 600. For the purposes of discussion, references will be made to... Figure 1 and Figure 2 To describe method 4000.

[0040] At box 4001, fault detection device 600 acquires current sensing information representing the multiphase current flowing through multiphase insulated conductor 400. As an example, current sensing device 410 can sense the multiphase current flowing through multiphase insulated conductor 400, and fault detection device 600 can receive sensing results from sensing device 410 indicating the current on multiphase insulated conductor 400.

[0041] At box 4002, based on the acquired current sensing information, the fault detection device 600 determines the actual value of the electrical quantity to be controlled for the motor 300. As an example, to effectively control the operation of the motor, the control device 500 needs to perform closed-loop control on some electrical quantities of the motor 300 during the control of the motor drive device 200, so that the electrical quantity to be controlled can reach the desired value, thereby achieving the control objective. For example, in a field-oriented control (FOC) algorithm, the control device 500 can control the magnetic field direction by performing closed-loop control on the direct-axis voltage or current of the motor, and control the torque by performing closed-loop control on the quadrature-axis voltage or current of the motor. Thus, when it is necessary to adjust the motor torque, the desired value of the quadrature-axis voltage or current can be changed, thereby achieving the torque regulation objective. The fault detection device 600 can calculate or estimate the current value of such electrical quantities to be controlled based on the current sensing information.

[0042] At box 4003, based on the difference between the actual and expected values ​​of the determined controlled electrical quantity, the fault detection device 600 generates an indication signal indicating a first-type fault in the multiphase insulated conductor 400. Specifically, in the event of a short-circuit or open-circuit fault in the multiphase insulated conductor 400, the current flowing through the multiphase insulated conductor 400 will change abruptly, causing the actual controlled electrical quantity to typically change significantly as well. However, the expected value of the controlled electrical quantity cannot change abruptly, thus an abnormal deviation will occur between the actual and expected values ​​of the controlled electrical quantity, indicating a short-circuit or open-circuit fault in the multiphase insulated conductor 400. By checking the rationality of the motor control process, it is possible to determine whether a fault has occurred in the multiphase insulated conductor 400 in a simple, low-cost, and rapid manner without adding additional equipment (such as high-frequency current sensors).

[0043] In some embodiments of this disclosure, the electrical quantities to be controlled include at least one of the following: direct-axis voltage, quadrature-axis voltage, direct-axis current, and quadrature-axis current of the motor 300. Specifically, coordinate transformation and a motor model corresponding to the motor 300 can be used to convert the multiphase current in the current sensing information into direct-axis current, quadrature-axis current, direct-axis voltage, and quadrature-axis voltage. Since the desired direct-axis current, desired quadrature-axis current, desired direct-axis voltage, and desired quadrature-axis voltage do not change abruptly during the control process, the occurrence of a fault can be determined by whether the actual values ​​of these electrical quantities deviate significantly from the desired values.

[0044] In some embodiments of this disclosure, if the difference between the actual value and the expected value of the direct-axis voltage determined based on current sensing information exceeds a first predetermined threshold, the fault detection device 600 can generate an indication signal indicating that the multiphase insulated conductor 400 has a first type of fault. Alternatively or additionally, if the difference between the actual value and the expected value of the quadrature-axis voltage determined based on current sensing information exceeds a second predetermined threshold, the fault detection device 600 can generate an indication signal indicating that the multiphase insulated conductor 400 has a first type of fault. Alternatively or additionally, if the difference between the actual value and the expected value of the direct-axis current determined based on current sensing information exceeds a third predetermined threshold, the fault detection device 600 can generate an indication signal indicating that the multiphase insulated conductor 400 has a first type of fault. Alternatively or additionally, if the difference between the actual value and the expected value of the quadrature-axis current determined based on current sensing information exceeds a fourth predetermined threshold, the fault detection device 600 can generate an indication signal indicating that the multiphase insulated conductor 400 has a first type of fault. The first to fourth predetermined thresholds can be set according to the actual situation of the motor, and are deviation values ​​that indicate a significant departure of the direct-axis electrical quantity and the quadrature-axis electrical quantity from the normal condition, so as to distinguish them from the normal control error in the closed-loop control process. In this way, as long as at least one of the electrical quantities of direct-axis current, quadrature-axis current, direct-axis voltage and quadrature-axis voltage deviates significantly during the control process, it can be determined that a short circuit or open circuit fault has occurred in the multiphase insulated conductor 400.

[0045] Alternatively or additionally, the fault detection device 600 determines the total voltage difference based on the difference between the determined direct-axis voltage and the desired direct-axis voltage, and the difference between the determined quadrature-axis voltage and the desired quadrature-axis voltage. If the total voltage difference exceeds a fifth threshold, an indication signal indicating a first-type fault has occurred in the multiphase insulated conductor 400 is generated. The fifth predetermined threshold can be set according to the actual situation of the motor and is a deviation value indicating that the direct-axis voltage and quadrature-axis voltage deviate significantly from the normal condition, to distinguish it from normal control errors in the closed-loop control process. In this way, both the difference related to the direct-axis voltage and the difference related to the quadrature-axis voltage can be considered, thereby improving the accuracy of fault diagnosis. In one embodiment, the total voltage difference includes the Euclidean norm of the difference between the determined direct-axis voltage and the desired direct-axis voltage, and the difference between the determined quadrature-axis voltage and the desired quadrature-axis voltage. Specifically, the sum of the squares of the difference between the actual and desired values ​​of the direct-axis voltage and the quadrature-axis voltage, and then the square root of the sum, can be calculated. In this way, both direct-axis voltage and quadrature-axis voltage can be used to determine the fault, and the accuracy can be improved.

[0046] Alternatively or additionally, the fault detection device 600 determines the total current difference based on the difference between the determined direct-axis current and the desired direct-axis current, and the difference between the determined quadrature-axis current and the desired quadrature-axis current. If the total current difference exceeds a sixth threshold, an indication signal indicating a first-type fault has occurred in the multiphase insulated conductor 400 is generated. The sixth predetermined threshold can be set according to the actual situation of the motor and is a deviation value indicating that the direct-axis current and quadrature-axis current deviate significantly from normal conditions, to distinguish them from normal control errors in the closed-loop control process. In this way, both the difference related to the direct-axis current and the difference related to the quadrature-axis current can be considered, thereby improving the accuracy of fault diagnosis. In one embodiment, the total current difference includes the Euclidean norm of the difference between the determined direct-axis current and the desired direct-axis current, and the difference between the determined quadrature-axis current and the desired quadrature-axis current. Specifically, the sum of the squares of the difference between the actual value and the desired value of the direct-axis current and the squares of the difference between the actual value and the desired value of the quadrature-axis current can be calculated, and then the square root of the sum can be calculated. In this way, both direct-axis and quadrature-axis currents can be used to determine faults, and the accuracy can be improved.

[0047] In some embodiments of this disclosure, the first type of fault includes at least one of the following: continuous short circuits in the multiphase insulated conductor 400 and continuous open circuits in the multiphase insulated conductor 400. For example, if the multiphase insulated conductor 400 completely detaches from the motor 300, resulting in continuous open circuits, the actual values ​​of the controlled electrical quantities, such as AC-axis voltage and AC-axis current, will become zero, but the expected values ​​will not change abruptly, and therefore can be detected by the fault detection device 600 using the fault detection method 4000. In another example, the completely detached multiphase insulated conductor 400 may come into contact with the vehicle body, resulting in continuous short circuits to ground in the multiphase insulated conductor 400. In this case, the actual values ​​of the controlled electrical quantities, such as AC-axis voltage and AC-axis current, will also change significantly, but the expected values ​​will not change abruptly, and therefore the fault detection device 600 can detect this fault condition using the fault detection method 4000. In addition, the fault detection device 600, using the fault detection method 4000, can also detect various other short-circuit and open-circuit faults, such as continuous phase-to-phase short circuits between the three phases, continuous short circuits and open circuits of some phases, etc.

[0048] In some embodiments of this disclosure, where the functionality of the fault detection device 600 is integrated into the control device 500, the control device 500 can control the motor drive 200 based on an indication signal indicating a first-type fault in the multiphase insulated conductor 400. For example, after determining that a short-circuit fault has occurred, the control device 500 can control the switching devices in the motor drive 200 to be in an off state, thereby stopping the power supply to the multiphase insulated conductor 400.

[0049] Figure 5 An exemplary internal block diagram of a fault detection device 600 implementing a fault detection method 4000 according to an embodiment of the present disclosure is shown. The following description uses a three-phase system as an example; however, embodiments of the present disclosure can also be applied to systems with other numbers of phases. The fault detection device 600 may include a conversion module 5001, a voltage calculation module 5002, a first difference module 5003, a second difference module 5004, a third difference module 5005, a fourth difference module 5006, a first calculation module 5007, a second calculation module 5008, a first comparison module 5009, a second comparison module 5010, a third comparison module 5011, a fourth comparison module 5012, a fifth comparison module 5013, a sixth comparison module 5014, and a generation module 5015.

[0050] The conversion module 5001 receives current sensing information representing the three-phase currents Ia, Ib, and Ic on the multi-phase insulated conductor 400, and converts the three-phase currents Ia, Ib, and Ic into direct-axis current Id and quadrature-axis current Iq through coordinate transformation. The voltage calculation module 5002 obtains the direct-axis current Id and quadrature-axis current Iq, and can also obtain the motor stator internal resistance Rs, motor direct-axis inductance Ld, motor quadrature-axis inductance Lq, and motor speed (e.g., angular velocity) ω from other sensing devices and / or storage devices (not shown in the figure). r and motor flux linkage ψ f Therefore, the direct-axis voltage Ud and quadrature-axis voltage Uq can be determined using the following equation:

[0051] Ud=Rs*Id-ω r *Lq*Iq (1)

[0052] Uq=Rs*Iq+ω r *Ld*Id+ω r *ψ f (2)

[0053] The first subtraction module 5003 compares the direct-axis voltage Ud output by the voltage calculation module 5002 with the desired direct-axis voltage Ud. * Subtract to determine the actual direct-axis voltage Ud and the desired direct-axis voltage Ud. * The difference ΔUd between them. The second difference module 5004 compares the quadrature-axis voltage Uq output by the voltage calculation module 5002 with the expected quadrature-axis voltage Uq. * Subtract them to determine the actual quadrature-axis voltage Uq and the desired quadrature-axis voltage Uq. * The difference ΔUq between the actual direct-axis current Id and the expected direct-axis current Id* is calculated by the third subtraction module 5005. The fourth subtraction module 5006 subtracts the quadrature-axis current Iq* output by the conversion module 5001 from the expected quadrature-axis current Iq* to determine the difference ΔIq between the actual quadrature-axis current Iq and the expected direct-axis current Iq*.

[0054] The first calculation module 5007 receives the difference ΔUd output by the first difference module 5003 and the difference ΔUq output by the second difference module 5004, and calculates their Euclidean norm as the total voltage difference ΔU according to the following equation:

[0055]

[0056] The second calculation module 5008 receives the difference ΔId output by the third difference module 5005 and the difference ΔIq output by the fourth difference module 5006, and calculates their Euclidean norm as the total current difference ΔI according to the following equation:

[0057]

[0058] The first comparison module 5009 compares the total voltage difference ΔU output by the first calculation module 5007 with the fifth threshold TH5, and outputs a valid signal to the generation module 5015 if the total voltage difference ΔU exceeds the fifth threshold TH5. The second comparison module 5010 compares the difference ΔUd output by the first difference module 5003 with the first threshold TH1, and outputs a valid signal to the generation module 5015 if the direct-axis voltage difference ΔUd exceeds the first threshold TH1. The third comparison module 5011 compares the difference ΔUq output by the second difference module 5004 with the second threshold TH2, and outputs a valid signal to the generation module 5015 if the quadrature-axis voltage difference ΔUq exceeds the second threshold TH2. The fourth comparison module 5012 compares the total current difference ΔI output by the second calculation module 5008 with the sixth threshold TH6, and outputs a valid signal to the generation module 5015 if the total current difference ΔI exceeds the sixth threshold TH6. The fifth comparison module 5013 compares the difference ΔId output by the third difference module 5005 with the third threshold TH3, and outputs a valid signal to the generation module 5015 if the difference ΔId of the direct-axis current exceeds the third threshold TH3. The sixth comparison module 5014 compares the difference ΔIq output by the fourth difference module 5006 with the fourth threshold TH4, and outputs a valid signal to the generation module 5015 if the difference ΔIq of the quadrature-axis current exceeds the fourth threshold TH4.

[0059] Upon receiving a valid signal from at least one of the comparison modules 5009 to 5014, the generation module 5015 can generate an indication signal indicating that a first-type fault has occurred in the multiphase insulated conductor 400. Thus, the fault detection device 600 can quickly and effectively detect faults in the multiphase insulated conductor 400 without requiring any additional high-cost equipment.

[0060] Figure 6 A schematic flowchart of a fault detection method 6000 according to another embodiment of the present disclosure is shown. Method 6000 can be performed in... Figure 1 and Figure 2 The method 6000 is implemented in the scenario described above and executed by the fault detection device 600. Alternatively, the method 6000 can also be executed by the control device 500, which integrates the functionality of the fault detection device 600. For the purposes of discussion, references will be made to... Figure 1 and Figure 2 To describe method 6000.

[0061] At box 6001, fault detection device 600 acquires current sensing information representing the multiphase current flowing through multiphase insulated conductor 400. As an example, fault detection device 600 can acquire sensing results indicating the current on multiphase insulated conductor 400 from sensing device 410.

[0062] At box 6002, the fault detection device 600 determines the sum of the multiphase currents based on the acquired current sensing information. As an example, the sensed three-phase currents can be summed. Under normal operating conditions, the sum of the three-phase currents is 0, or fluctuates around 0, while in the event of a fault (such as a grounding circuit), the sum of the three-phase currents will increase significantly.

[0063] At box 6003, the fault detection device 600 determines whether the sum of the multiphase currents exceeds a predetermined current threshold. As an example, the predetermined current threshold can be a current level that indicates the occurrence of a fault, such as 20A, 30A, 40A, or 50A, and can be set according to the actual situation and the type of fault to be detected. Therefore, by comparing the sum of the multiphase currents with the predetermined current threshold, it can be determined whether a line fault has occurred.

[0064] At block 6004, in response to the sum of the multiphase currents exceeding a predetermined current threshold, the fault detection device 600 increments a count value. As an example, the fault detection device 600 can compare the sum of the multiphase currents with the predetermined current threshold. Furthermore, a counter can be provided that counts based on the result of each comparison. Once the sum of the multiphase currents exceeds the predetermined current threshold, the counter value is incremented by one. Alternatively, if the sum of the multiphase currents does not exceed the predetermined current threshold, the process returns to block 6001.

[0065] At box 6005, the fault detection device 600 determines whether the count increase within a predetermined time period exceeds a threshold. Specifically, the count increase within the predetermined time period indicates the number of times the sum of multiphase currents exceeds the threshold within a certain period. Thus, the fault detection device 600 can determine whether the sum of multiphase currents increases frequently in a short period of time. The threshold used for the count increase can be set according to the actual situation, and it is necessary to exclude situations where the increase in the sum of multiphase currents is not caused by a fault (for example, during motor control, the sum of three-phase or multiphase currents may occasionally increase). As an example, the fault detection device 600 can be equipped with a timer to determine the range of the predetermined time period, and the timer can reset the count value to zero after the predetermined time period, so that the current count value of the counter can directly represent the count increase value (i.e., the number of times the sum of multiphase currents exceeds the threshold) within the current period.

[0066] At box 6006, in response to the count increase exceeding a threshold within a predetermined time period, the fault detection device 600 generates an indication signal indicating a second type of fault in the multiphase insulated conductor 400. For example, if the count increase within the predetermined time period is excessive, it indicates that the sum of the multiphase currents has repeatedly exceeded the predetermined current threshold during this period, suggesting a fault in the multiphase insulated conductor 400. During motor control, the sum of the multiphase currents fluctuates, and may occasionally exceed the predetermined current threshold due to control-related reasons; however, this situation does not persist or occur frequently in a short period. By observing the count increase within the predetermined time period, fluctuations in the sum of the multiphase currents caused by non-fault factors can be ruled out, and the fault condition can be accurately determined. Alternatively, if the count increase within the predetermined time period does not exceed the threshold, the process returns to box 6001.

[0067] In some embodiments of this disclosure, the second type of fault includes at least one of the following: continuous short circuits in the multiphase insulated conductor 400, discontinuous multiple short circuits in the multiphase insulated conductor 400, continuous open circuits in some phases of the multiphase insulated conductor 400, and discontinuous multiple open circuits in some phases of the multiphase insulated conductor 400. For example, the conductive core of the multiphase insulated conductor 400 may be exposed due to wear, and with the oscillations during vehicle operation, the exposed conductive core may intermittently contact the vehicle's housing, causing discontinuous multiple ground faults. In this case, the fault detection device 600 can detect that the sum of the multiphase currents exceeds a threshold multiple times within a short period of time, thereby determining that a fault has occurred. Furthermore, the fault detection device 600, using the fault detection method 6000, can also detect various other short circuit and open circuit faults, such as continuous phase-to-phase open circuits or short circuits to ground.

[0068] In some embodiments of this disclosure, where the functionality of the fault detection device 600 is integrated into the control device 500, the control device 500 can control the motor drive 200 based on an indication signal indicating a second type of fault in the multiphase insulated conductor 400. For example, after determining that an open-circuit fault has occurred due to the insulated conductor falling off, the control device 500 can control the switching devices in the motor drive 200 to be in the off state, thereby stopping the power supply to the multiphase insulated conductor 400 and the motor 300.

[0069] Figure 7An exemplary internal block diagram of a fault detection device 600 implementing a fault detection method 6000 according to another embodiment of the present disclosure is shown. The following description uses a three-phase system as an example; however, embodiments of the present disclosure can also be applied to systems with other numbers of phases. The fault detection device 600 may include a summing module 7001, a first comparison module 7002, a timing module 7003, a counting module 7004, and a second comparison module 7005.

[0070] The summation module 7001 receives current sensing information representing the three-phase currents Ia, Ib, and Ic on the multi-phase insulated conductor 400, and sums the three-phase currents Ia, Ib, and Ic to output the sum of the three-phase currents Isum. The first comparison module 7002 compares the sum of the three-phase currents Isum with a predetermined current threshold THcurrent. In each comparison, if the sum of the three-phase currents Isum exceeds the predetermined current threshold THcurrent, the counting module 7004 increments the current count value by one. The timing module 7003 resets itself and resets the count value of the counting module 7004 to zero after a predetermined time period. Thus, the current count value of the counting module 7004 can effectively represent the number of times the sum of the three-phase currents Isum exceeds the predetermined current threshold THcurrent within a predetermined time period. The second comparison module 7005 compares the current count value of the counting module 7004 with a counting threshold THcount. If the current count value of the counting module 7004 exceeds the counting threshold THcount, it indicates that the sum of the three-phase currents has increased frequently in a short period of time. As a result, the second comparison module 7005 can generate an indication signal that the multi-phase insulated conductor 400 has a second type of fault.

[0071] Figure 8 A schematic waveform diagram of the multiphase current and the sum of the multiphase currents is shown in the case of a short-circuit fault in the multiphase insulated conductor 400. In the case where the multiphase insulated conductor 400 is a three-phase conductor, Figure 8 The waveform above represents the waveform of the three-phase current flowing through the three-phase conductors, and Figure 8The waveform below shows the waveform of the sum of the three-phase currents. Before 73800s, the multiphase insulated conductor 400 was operating normally without fault, and under these conditions, the sum of the three-phase currents was essentially zero. After 73800s, the multiphase insulated conductor 400 broke and intermittently contacted the vehicle body due to vehicle vibrations, causing a short circuit to ground. In the waveform below, the sum of the three-phase currents increased frequently within a short period of time after 73800s. The fault detection device 600 determines the sum of the three-phase currents and judges whether the sum of the three-phase currents exceeded a threshold too many times within a certain period. For example, if the fault detection device 600 detects that the sum of the three-phase currents exceeded a predetermined current threshold of 40A more than 4 times within a predetermined period, it can determine that a short circuit fault has occurred in the multiphase insulated conductor 400.

[0072] Furthermore, the steps in fault detection method 4000 and the steps in fault detection method 6000 can be executed in parallel or sequentially. In some embodiments, Figure 4 Boxes 4002 and 4003 in the middle can be Figure 6 Execution follows box 6006. In some embodiments, Figure 6 Boxes 6002 to 6006 in the middle can be Figure 4 Execution follows box 4003. In some embodiments, Figure 4 Boxes 4002 and 4003 in the text can be used with Figure 6 Boxes 6002 to 6006 in the code are executed in parallel.

[0073] Specifically, fault detection method 4000 involves detecting faults by performing a rationality check through monitoring controlled electrical quantities such as AC and DC axis electrical quantities, while fault detection method 6000 involves detecting faults by monitoring changes in the sum of multiphase currents. To improve detection effectiveness, a rationality check can be performed after detecting changes in the sum of multiphase currents, or after performing a rationality check, or both can be performed in parallel. The detection process of fault detection method 4000 is either a one-time event or performed at certain time intervals, therefore it may not detect multiple short circuits within a short period of time, such as discontinuous multiple short circuits caused by worn insulated wires intermittently contacting the vehicle body due to oscillations. Furthermore, the detection process of fault detection method 6000 depends on a significant change in the sum of multiphase currents caused by a fault; however, if a fault condition such as the multiphase insulated wire 400 detaching from the motor 300 occurs, the sum of multiphase currents will always be zero, resulting in the failure to detect the detachment fault. Therefore, by combining fault detection method 4000 and fault detection method 6000, fault monitoring of the line can be more comprehensive, thereby ensuring the safety of the line. Furthermore, the first type of faults covered by fault detection method 4000 and the second type of faults covered by fault detection method 6000 both involve many of the same faults. For these faults, the two detection schemes can be used to cross-verify during the detection process to prevent missed or false alarms, thereby improving the accuracy of fault detection.

[0074] Figure 9 A schematic block diagram of a fault detection apparatus 900 according to an embodiment of the present disclosure is shown. The apparatus 900 can be implemented as follows: Figure 1 and Figure 2 Fault detection equipment 600. For example... Figure 9 As shown, the device 900 includes an acquisition unit 901 configured to acquire current sensing information representing a multiphase current flowing through a multiphase insulated conductor 400 connected between the motor drive device 200 and the motor 300. The device 900 also includes a determination unit 902 configured to determine the actual value of a controllable electrical quantity of the motor 300 based on the acquired current sensing information. Furthermore, the device 900 includes a generation unit 903 configured to generate an indication signal indicating a first-type fault in the multiphase insulated conductor 400 based on the difference between the determined actual value and the expected value of the controllable electrical quantity.

[0075] Figure 10 A schematic block diagram of a fault detection apparatus 1000 according to another embodiment of the present disclosure is shown. The apparatus 1000 can be implemented as follows: Figure 1 and Figure 2Fault detection equipment 600. For example... Figure 10 As shown, the device 1000 includes an acquisition unit 1001 configured to acquire current sensing information representing multiphase current flowing through a multiphase insulated conductor 400 connected between the motor drive device 200 and the motor 300. The device 1000 also includes a determination unit 1002 configured to determine the sum of the multiphase currents based on the acquired current sensing information. The device 1000 further includes a counting unit 1003 configured to increment a count value in response to the sum of the multiphase currents exceeding a current threshold. Furthermore, the device 1000 includes a generation unit 1004 configured to generate an indication signal indicating a second type of fault in the multiphase insulated conductor 400 in response to the count increment exceeding a threshold within a predetermined time period.

[0076] Those skilled in the art will understand that the various steps of the methods disclosed above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using device-executable program code, which can then be stored in a storage device for execution by the computing device. Alternatively, they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this disclosure is not limited to any particular combination of hardware and software.

[0077] It should be understood that although several devices or sub-devices of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more devices described above can be embodied in one device. Conversely, the features and functions of one device described above can be further divided and embodied by multiple devices.

[0078] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A fault detection method, comprising: Acquire (4001) current sensing information, the current sensing information representing the multiphase current flowing through a multiphase insulated conductor (400), the multiphase insulated conductor (400) being connected between the motor drive device (200) and the motor (300); The actual value of the electrical quantity to be controlled in the motor (300) is determined based on the acquired current sensing information (4002); as well as Based on the difference between the actual value and the expected value of the determined electrical quantity to be controlled, an indication signal indicating that the multiphase insulated conductor (400) has a first type of fault is generated (4003).

2. The fault detection method according to claim 1, wherein the electrical quantity to be controlled includes at least one of the direct-axis voltage, quadrature-axis voltage, direct-axis current and quadrature-axis current of the motor (300).

3. The fault detection method according to claim 1 or 2 further includes: The sum of the multiphase currents (6002) is determined based on the acquired current sensing information; In response to the sum of the multiphase currents exceeding a current threshold, the count value is incremented (6004); and In response to the count value increasing beyond a threshold within a predetermined time period, an indication signal indicating a second type of fault is generated (6006) in the multiphase insulated conductor (400).

4. The fault detection method according to claim 3, The first type of fault includes at least one of the following: continuous short circuits in the multiphase insulated conductor (400), and continuous open circuits in the multiphase insulated conductor (400); and The second type of fault includes at least one of the following: continuous short circuits in the multiphase insulated conductor (400), multiple discontinuous short circuits in the multiphase insulated conductor (400), continuous open circuits in some phases of the multiphase insulated conductor (400), and multiple discontinuous open circuits in some phases of the multiphase insulated conductor (400).

5. The fault detection method according to claim 1 or 3 further includes: The motor drive device (200) is controlled based on the indication signal.

6. The fault detection method according to claim 2, wherein generating (4003) an indication signal indicating that the multiphase insulated conductor (400) has a first type of fault based on the difference between the actual value and the expected value of the determined electrical quantity to be controlled includes: An indication signal indicating a first-type fault in the multiphase insulated conductor (400) is generated based on at least one of the following: The difference between the determined direct-axis voltage and the desired direct-axis voltage exceeds a first threshold. The difference between the determined cross-axis voltage and the desired cross-axis voltage exceeds the second threshold. The difference between the determined direct-axis current and the desired direct-axis current exceeds the third threshold. The difference between the determined cross-axis current and the desired cross-axis current exceeds the fourth threshold. The total voltage difference is determined based on the difference between the determined direct-axis voltage and the desired direct-axis voltage and the difference between the determined quadrature-axis voltage and the desired quadrature-axis voltage, and the total voltage difference exceeds a fifth threshold. as well as The total current difference is determined based on the difference between the determined direct-axis current and the desired direct-axis current, and the difference between the determined quadrature-axis current and the desired quadrature-axis current, and the total current difference exceeds a sixth threshold.

7. The fault detection method according to claim 6, The total voltage difference includes the Euclidean norm of the difference between the determined direct-axis voltage and the desired direct-axis voltage, and the difference between the determined quadrature-axis voltage and the desired quadrature-axis voltage. The total current difference includes the Euclidean norm of the difference between the determined direct-axis current and the desired direct-axis current, and the difference between the determined quadrature-axis current and the desired quadrature-axis current.

8. A fault detection method, comprising: Acquire (6001) current sensing information, the current sensing information representing multiphase current flowing through a multiphase insulated conductor (400), the multiphase insulated conductor (400) being connected between a motor drive device (200) and a motor (300); The sum of the multiphase currents (6002) is determined based on the acquired current sensing information; In response to the sum of the multiphase currents exceeding a current threshold, the count value is incremented (6004); and In response to the count value increasing beyond a threshold within a predetermined time period, an indication signal indicating a second type of fault is generated (6006) in the multiphase insulated conductor (400).

9. The fault detection method according to claim 8, wherein the second type of fault includes at least one of the following: continuous short circuits in the multiphase insulated conductor (400), multiple discontinuous short circuits in the multiphase insulated conductor (400), continuous open circuits in some phases of the multiphase insulated conductor (400), and multiple discontinuous open circuits in some phases of the multiphase insulated conductor (400).

10. The fault detection method according to claim 8, further comprising: The motor drive device (200) is controlled based on the indication signal.

11. A device (900) for fault detection, comprising: The acquisition unit (901) is configured to acquire current sensing information representing a multiphase current flowing through a multiphase insulated conductor (400) connected between a motor drive device (200) and a motor (300). The determining unit (902) is configured to determine the actual value of the electrical quantity to be controlled of the motor (300) based on the acquired current sensing information; as well as The generation unit (903) is configured to generate an indication signal indicating that a first type of fault has occurred in the multiphase insulated conductor (400) based on the difference between the actual value and the expected value of the determined electrical quantity to be controlled.

12. A device (1000) for fault detection, comprising: The acquisition unit (1001) is configured to acquire current sensing information, which represents a multiphase current flowing through a multiphase insulated conductor (400) connected between a motor drive device (200) and a motor (300). The determining unit (1002) is configured to determine the sum of the multiphase currents based on the acquired current sensing information; The counting unit (1003) is configured to increment the count value in response to the sum of the multiphase currents exceeding a current threshold; and The generation unit (1004) is configured to generate an indication signal indicating that the multiphase insulated conductor (400) has a second type of fault in response to the count value increasing by more than a threshold within a predetermined time period.

13. A fault detection device (600) adapted to be coupled to a motor (300) and a multiphase insulated wire (400) connected between a motor drive (200) and the motor (300), the fault detection device being configured to perform a fault detection method according to any one of claims 1 to 8.

14. A vehicle comprising: A motor drive unit (200), a motor (300), and a multiphase insulated wire (400) connecting the motor drive unit (200) and the motor (300); and The fault detection device (600) according to claim 13.

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