An insulation detection method for a motor controller

Abstract

The present invention discloses an insulation detection method for a motor controller, which relates to the technical field of electric vehicles and includes the following steps: The DSP control board controls the turn-off of the IGBT module through the drive control board and ensures that the current of the three-phase AC motor is 0A; The DSP control board first controls the access of the low-voltage power supply and adjusts the theoretical voltage of the insulation detection module through the voltage regulation circuit; Then, the actual voltage of the insulation detection module is collected through the first sampling point A1, and the insulation resistance value of the resistor RM is calculated according to the deviation between the theoretical voltage and the actual voltage, so as to judge the insulation fault level of the three-phase AC motor; The DSP control board controls the disconnection of the low-voltage power supply and executes corresponding countermeasures according to the determined insulation fault level. The insulation detection module of the present invention can accurately detect the insulation problem at the AC end of the motor, and can quickly protect the motor controller after an insulation fault occurs at the AC end of the motor, thereby solving the problems existing in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and particularly relates to an insulation detection method for a motor controller. Background Art

[0002] With the rapid growth of the electric vehicle industry, more and more electric vehicles have entered the market. The safety issue of the whole vehicle has gradually become one of the important indicators concerned by the industry. As an important part of the safety of the electric vehicle whole vehicle, the response speed of the insulation detection system directly has a significant impact on the safety of pure electric vehicles and passengers.

[0003] The insulation detection method for pure electric vehicles usually assembles an insulation monitor on the whole vehicle to detect the insulation of the whole vehicle. However, at present, the insulation detector can only detect the insulation value of the positive and negative of the bus voltage at the high-voltage DC end with respect to the body ground of the whole vehicle. In the case where the IGBT of the motor controller is not switched, it is impossible to detect the AC insulation problem at the motor end of the drive system. Therefore, when an insulation fault occurs in the motor, the insulation detector cannot quickly protect the motor controller in time, and the system still continues to operate, eventually leading to the continuous deterioration of the fault problem, and finally causing major faults in the motor controller, such as IGBT faults and drive board faults. After the device failure of the motor controller is caused by the insulation fault at the motor end, the insulation monitor can detect it, but this has already caused a system chain fault, resulting in an increase in maintenance costs. Summary of the Invention

[0004] The present invention provides an insulation detection method for a motor controller, and its main purpose is to solve the problems existing in the prior art.

[0005] The present invention adopts the following technical solutions:

[0006] An insulation detection method for a motor controller, the motor controller includes a control module and an insulation detection module; the control module includes a DSP control board, a drive control board, an IGBT module, and a three-phase AC motor connected in sequence, and a resistor RM is provided at the grounding end of the three-phase AC motor; the insulation detection module includes a low-voltage power supply, a DCDC converter, a voltage regulating circuit, a signal processing circuit, and the DSP control board connected in sequence; a first sampling point A is provided between the voltage regulating circuit and the signal processing circuit 1 , and a second sampling point A is provided between the IGBT module and the three-phase AC motor 2 , the first sampling point A 1 is connected in series with the second sampling point A 2 ;

[0007] The insulation detection method includes the following steps:

[0008] S1. The DSP control board controls the IGBT module to turn off the tube through the drive control board and ensures that the current of the three-phase AC motor is 0A;

[0009] S2. The DSP control board first controls the access of the low-voltage power supply and adjusts the theoretical voltage of the insulation detection module through the voltage regulation circuit; then through the first sampling point A 1 collects the actual voltage of the insulation detection module and calculates the insulation resistance value of the resistor RM according to the deviation between the theoretical voltage and the actual voltage, so as to judge the insulation fault level of the three-phase AC motor;

[0010] S3. The DSP control board controls the disconnection of the low-voltage power supply and executes corresponding countermeasures according to the determined insulation fault level.

[0011] Furthermore, the insulation fault levels include first-level insulation fault, second-level insulation fault and no insulation fault; the countermeasures for the first-level insulation fault are: prohibiting the system from applying high voltage and the motor controller stops working; the countermeasures for the second-level insulation fault are: the system applies high voltage and the motor controller operates in a power-limiting mode; the countermeasures for no insulation fault are: the system applies high voltage and the motor controller works normally.

[0012] Even further, the step S2 includes the following sub-steps:

[0013] S21. The DSP control board first adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit 11 , and then through the first sampling point A 1 collects the actual voltage V of the insulation detection module 12 , and calculates the insulation resistance value R of the resistor RM at this time according to the deviation between the theoretical voltage V 11 and the actual voltage V 12 , so as to judge whether the insulation fault level of the three-phase AC motor belongs to the first-level insulation fault. If it belongs to the first-level insulation fault, execute step S3; otherwise execute step S22; 11

[0014] S22. The DSP control board first adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit 21 , and then through the first sampling point A 1 collects the actual voltage V of the insulation detection module 22 , and calculates the insulation resistance value R of the resistor RM at this time according to the deviation between the theoretical voltage V 21 and the actual voltage V 22 , so as to judge whether the insulation fault level of the three-phase AC motor belongs to the second-level insulation fault. If it belongs to the second-level insulation fault, execute step S3, otherwise execute step S23; 21

[0015] ​​S23. The DSP control board determines that there is no insulation fault in the three-phase AC motor and executes step S3.

[0016] Furthermore, the voltage regulating circuit includes a first voltage regulating circuit and a second voltage regulating circuit connected to each other; a first sampling point A is provided between the first voltage regulating circuit and the second voltage regulating circuit. 1 .

[0017] Still further, the first voltage regulating circuit includes resistors R1A, R1B, and R1C connected in series; the second voltage regulating circuit includes resistors R1D and R1E connected in series; switches K1C, K1D, and K1E are respectively provided for the resistors R1C, R1D, and R1E; in step S21, the DSP control board disconnects the switches K1C, K1D, and K1E to adjust the theoretical voltage V of the insulation detection module. 11 ; in step S22, the DSP control board closes the switch K1D and disconnects the switches K1C and K1E to adjust the theoretical voltage V of the insulation detection module. 21 .

[0018] Still further, in step S23, the DSP control board closes the switches K1C and K1D and disconnects the switch K1E to adjust the theoretical voltage V of the insulation detection module. 31 , and thereby calculates and records the insulation resistance value R under the condition of no insulation fault. 31 .

[0019] Further, the signal processing circuit includes an opto-isolation circuit, a signal amplification circuit, a filtering circuit, and a protection circuit connected in sequence.

[0020] Further, a switch K1A is provided between the DCDC converter and the voltage regulating circuit, and the DSP control board controls the connection or disconnection of the low-voltage power supply by controlling the closing or opening of the switch K1A.

[0021] Further, the control module further includes a current sampling board; current transformers are provided on the three-phase lines of the three-phase AC motor, and the DSP control board collects the information of each current transformer through the current sampling board.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The present invention deeply integrates the insulation detection module with the control module of the motor controller, and the two share a main chip, and information interaction can be carried out without a CAN bus, effectively improving the fault response speed.

[0024] 2. The insulation detection module of the present invention can accurately detect the insulation problems at the AC end of the motor, and can quickly protect the motor controller after an insulation fault occurs at the AC end of the motor, thus solving the problems existing in the prior art.

[0025] 3. The present invention classifies the insulation faults at the AC end of the motor and sets different safety management strategies according to different fault levels, thereby realizing intelligent and accurate insulation fault handling, and effectively improving the fault detection and handling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the present invention.

[0027] Figure 2 It is a control flow chart of the present invention.

[0028] In the figure: 1 - DSP control board; 2 - drive control board; 3 - IGBT module; 4 - three-phase AC motor; 5 - DCDC converter; 6 - first voltage regulating circuit; 7 - second voltage regulating circuit; 8 - signal processing circuit; 9 - current sampling board. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following describes the specific embodiments of the present invention with reference to the accompanying drawings. In order to fully understand the present invention, many details are described below, but for those skilled in the art, the present invention can be implemented without these details.

[0030] As Figure 1 shown, a motor controller integrated with an insulation detection module includes a control module and an insulation detection module; the control module includes a DSP control board 1, a drive control board 2, an IGBT module 3, and a three-phase AC motor 4 connected in sequence, and a resistor RM is provided at the grounding end of the three-phase AC motor 4; the insulation detection module includes a low-voltage power supply, a DCDC converter 5, a voltage regulating circuit, a signal processing circuit 8, and a DSP control board 1 connected in sequence; a first sampling point A is provided between the voltage regulating circuit and the signal processing circuit 8 1 , and a second sampling point A is provided between the IGBT module 3 and the three-phase AC motor 4 2 , the first sampling point A 1 and the second sampling point A 2 are connected in series with each other. The mutually connected first sampling point A 1 and the second sampling point A 2 are equipotential sampling points. Therefore, by collecting the actual voltage of the first sampling point A 1 , the insulation resistance value R of the resistor RM can be calculated, and thus it can be determined whether there is an insulation fault in the three-phase AC motor 4.

[0031] As Figure 1As shown, the signal processing circuit 8 includes an optocoupler isolation circuit, a signal amplification circuit, a filtering circuit, and a protection circuit connected in sequence. The signal at the first sampling point A 1 is isolated from low voltage and high voltage by the optocoupler isolation circuit, amplified by the signal amplification circuit, filtered by the filtering circuit, and finally processed and analyzed by the ADC sampling module of the DSP control board 1 via the protection circuit, thereby fully ensuring the accuracy and precision of sampling.

[0032] As Figure 1 shown, a switch K1A is provided between the DCDC converter 5 and the voltage regulating circuit. The switch K1A is electrically connected to the DSP control board 1. The DSP control board 1 controls the closing or opening of the switch K1A to control the access or disconnection of the low-voltage power supply. As a preferred solution: the low-voltage power supply is a 24V lead-acid battery.

[0033] As Figure 1 shown, the voltage regulating circuit includes a first voltage regulating circuit 6 and a second voltage regulating circuit 7 connected to each other; a first sampling point A 1 is provided between the first voltage regulating circuit 6 and the second voltage regulating circuit 7. Specifically, the first voltage regulating circuit 6 includes resistors R1A, R1B, and R1C connected in series; and a switch K1C electrically connected to the DSP control board 1 is provided for the resistor R1C. The second voltage regulating circuit 7 includes resistors R1D and R1E connected in series. A switch K1D electrically connected to the DSP control board 1 is provided for the resistor R1D, and a switch K1E electrically connected to the DSP control board 1 is provided for the resistor R1E. During the detection process, the DSP control board 1 controls the opening and closing of the switches K1C, K1D, and K1E to control the voltage-dividing resistors of the first voltage regulating circuit 6 and the second voltage regulating circuit 7, thereby accurately adjusting the theoretical voltage of the insulation detection module according to requirements, and further more precisely analyzing the insulation resistance value of the motor. The switches K1A, K1C, K1D, and K1E are all electronic switches with fast response speeds, which can avoid the long detection time and the poor driving experience caused thereby.

[0034] As Figure 1 shown, the control module further includes a current sampling board 9. Current transformers are provided on the three-phase lines of the three-phase AC motor 4. One end of the current sampling board 9 is connected to the current transformer, and the other end is connected to the DSP control board 1. Therefore, the DSP control board 1 collects the information of the current transformer through the current sampling board 9.

[0035] As Figure 1 shown, the control module further includes high-voltage relays K1, K2, a capacitor C1, and a resistor R1 connected to the DC bus. The capacitor C1 and the resistor R1 form a discharge circuit of the control module. Before starting the insulation detection, both the high-voltage relays K1 and K2 are disconnected, and the DSP control board 1 controls the capacitor C1 to discharge automatically, thereby ensuring that the voltage value of the capacitor C1 is 0V.

[0036] As Figure 1 and Figure 2 shown, the insulation detection method of the above motor controller includes the following core steps:

[0037] S1. The DSP control board 1 controls the IGBT module 3 to turn off the switch through the drive control board 2, and ensures that the current of the three-phase AC motor 4 is 0A;

[0038] S2. The DSP control board 1 first controls the access of the low-voltage power supply and adjusts the theoretical voltage of the insulation detection module through the voltage regulation circuit; then collects the actual voltage of the insulation detection module through the first sampling point A 1 and calculates the insulation resistance value of the resistor RM according to the deviation between the theoretical voltage and the actual voltage, so as to judge the insulation fault level of the three-phase AC motor 4;

[0039] S3. The DSP control board 1 controls the disconnection of the low-voltage power supply and executes corresponding countermeasures according to the determined insulation fault level.

[0040] As Figure 1 and Figure 2 shown, specifically, the insulation fault levels include primary insulation fault, secondary insulation fault and no insulation fault. Among them, the primary fault is the highest-level fault, and the system does not apply high voltage and needs to be maintained and inspected; the secondary insulation fault is the secondary insulation fault, and it is recommended to operate with limited power and go to the maintenance site for maintenance. Therefore, the countermeasures for the primary insulation fault are: prohibiting the system from applying high voltage and the motor controller stops working. The countermeasures for the secondary insulation fault are: the system applies high voltage and the motor controller operates in a limited power mode. The countermeasures for no insulation fault are: the system applies high voltage and the motor controller works normally.

[0041] As Figure 1 and Figure 2 shown, in order to more clearly elaborate the above insulation detection method, the following details its specific control process:

[0042] Step S100: The system key is powered on.

[0043] Step S101: The high-voltage relays K1 and K2 are not closed.

[0044] Step S102: The DSP control board 1 detects whether the voltage value of the capacitor C1 is 0V. If so, execute step S103; otherwise, perform a quick discharge until the voltage value drops to 0V.

[0045] Step S103: The drive control board 2 is not enabled, and all transistors of the IGBT module 3 are turned off.

[0046] Step S104: The DSP control board 1 determines that the current value of the three-phase AC motor 4 is 0 A through the current sampling board 9.

[0047] Step S105: The DSP control board 1 controls the DCDC converter 5 to start working and controls the switch K1A to close, thereby connecting to the low-voltage power supply.

[0048] Step S106: The DSP control board 1 adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit. 11 In this embodiment, the DSP control board 1 adjusts the theoretical voltage V of the insulation detection module by controlling the switches K1C, K1D, and K1E to be disconnected. 11 .

[0049] Step S107: The DSP control board 1 collects the actual voltage V of the insulation detection module through the first sampling point A. 1 12 .

[0050] Step S108: The DSP control board 1 calculates the insulation resistance value R of the resistor RM at this time according to the deviation between the theoretical voltage V and the actual voltage V. 11 12 11 .

[0051] Step S109: The DSP control board 1 determines whether the insulation fault level of the three-phase AC motor 4 belongs to the first-level insulation fault according to the insulation resistance value R of the resistor RM. If so, execute Step S110; otherwise, execute Step S112. 11

[0052] Step S110: The DSP control board 1 controls the switch K1A to disconnect and simultaneously controls the DCDC converter 5 to stop working, thereby disconnecting the low-voltage power supply.

[0053] Step S111: The DSP control board 1 issues a first-level insulation fault alarm to the system, prohibits the system from applying high voltage, disables the drive control board 2, and prohibits the IGBT from turning on.

[0054] Step S112: The DSP control board 1 adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit. 21 In this embodiment, the DSP control board 1 controls the switch K1D to close and controls the switches K1C and K1E to be disconnected, thereby adjusting the theoretical voltage V of the insulation detection module. 21 .

[0055] Step S113: The DSP control board 1 collects the actual voltage V of the insulation detection module through the first sampling point A. 1 22 .

[0056] Step S114: The DSP control board 1 calculates the insulation resistance value R of the resistor RM at this time according to the deviation between the theoretical voltage V 21 and the actual voltage V 22 . 21 .

[0057] Step S115: The DSP control board 1 determines whether the insulation fault level of the three-phase AC motor 4 belongs to the secondary insulation fault according to the insulation resistance value R of the resistor RM 21 . If so, step S116 is executed; otherwise, step S119 is executed.

[0058] Step S116: The DSP control board 1 controls the switch K1A to disconnect, and at the same time controls the DCDC converter 5 to stop working, thereby disconnecting the low-voltage power supply.

[0059] Step S117: The DSP control board 1 issues a secondary insulation fault alarm to the system, the system powers on high voltage, and the motor controller operates in a power-limiting mode.

[0060] Step S118: The DSP control board 1 continuously detects whether there is Hall abnormality in the three-phase current through the current detection board 9. If so, the corresponding fault handling mechanism is enabled, and step S101 is repeated for insulation detection.

[0061] Step S119: The DSP control board 1 determines that the three-phase AC motor 4 has no insulation fault. To monitor the insulation resistance value without insulation fault under different voltage division conditions, a safe and redundant detection process is set here in this embodiment: the DSP control board 1 controls the switch K1C and the switch K1D to close, and controls the switch K1E to disconnect, thereby adjusting the theoretical voltage V of the insulation detection module 31 , and calculates and records the insulation resistance value R without insulation fault accordingly 31 . The insulation resistance value R 31 provides a judgment basis for setting the standard threshold value without insulation fault.

[0062] Step S120: The DSP control board 1 controls the switch K1A to disconnect, and at the same time controls the DCDC converter 5 to stop working, thereby disconnecting the low-voltage power supply.

[0063] Step S121: The DSP control board 1 issues an information of no insulation fault to the system, the system powers on high voltage, and the motor controller operates normally.

[0064] Step S122: The DSP control board 1 continuously detects whether there is Hall abnormality in the three-phase current through the current detection board 9. If so, the corresponding fault handling mechanism is enabled, and step S101 is repeated for insulation detection.

[0065] The above are only the specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification of the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention.

Claims

1. An insulation detection method for a motor controller, characterized in that: The motor controller includes a control module and an insulation detection module; the control module includes a DSP control board, a drive control board, an IGBT module, and a three-phase AC motor connected in sequence, and a resistor RM is provided at the grounding end of the three-phase AC motor; the insulation detection module includes a low-voltage power supply, a DCDC converter, a voltage regulation circuit, a signal processing circuit, and the DSP control board connected in sequence; a first sampling point A is provided between the voltage regulation circuit and the signal processing circuit 1 , and a second sampling point A is provided between the IGBT module and the three-phase AC motor 2 , the first sampling point A 1 is connected in series with the second sampling point A 2 ; the insulation detection method includes the following steps: S1. The DSP control board controls the IGBT module to turn off through the drive control board and ensures that the current of the three-phase AC motor is 0A; S2. The DSP control board first controls the access of the low-voltage power supply and adjusts the theoretical voltage of the insulation detection module through the voltage regulation circuit; then, through the first sampling point A 1 collects the actual voltage of the insulation detection module, calculates the insulation resistance value of the resistor RM according to the deviation between the theoretical voltage and the actual voltage, and thus judges the insulation fault level of the three-phase AC motor; S3. The DSP control board controls the low-voltage power supply to disconnect and executes corresponding countermeasures according to the determined insulation fault level.

2. An insulation detection method for a motor controller according to claim 1, characterized in that: the insulation fault levels include a first-level insulation fault, a second-level insulation fault, and no insulation fault; the countermeasure for the first-level insulation fault is: prohibit the system from applying high voltage and the motor controller stops working; the countermeasure for the second-level insulation fault is: the system applies high voltage and the motor controller operates in a power-limited mode; the countermeasure for no insulation fault is: the system applies high voltage and the motor controller works normally.

3. An insulation detection method for a motor controller according to claim 2, characterized in that: the following sub-steps are included in the step S2: S21, DSP control board first adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit 11 , then through the first sampling point A 1 Collect the actual voltage V of the insulation detection module 12 , and according to the theoretical voltage V 11 The actual voltage V 12 The deviation of the insulation resistance R of the resistor RM is calculated at this time. 11 , thereby determining whether the insulation fault level of the three-phase AC motor belongs to a first-level insulation fault, if it belongs to a first-level insulation fault, executing step S3; otherwise, executing step S22; S22, DSP control board first adjusts the theoretical voltage V of the insulation detection module through the voltage regulation circuit 21 , then through the first sampling point A 1 Collect the actual voltage V of the insulation detection module 22 , and according to the theoretical voltage V 21 The actual voltage V 22 The deviation of the insulation resistance R of the resistor RM is calculated at this time. 21 , thereby determining whether the insulation fault level of the three-phase AC motor belongs to a secondary insulation fault, if it belongs to a secondary insulation fault, executing step S3, otherwise executing step S23; S23. The DSP control board determines that there is no insulation fault in the three-phase AC motor and executes step S3.

4. An insulation detection method for a motor controller according to claim 3, characterized in that: The voltage regulating circuit includes a first voltage regulating circuit and a second voltage regulating circuit connected to each other; a first sampling point A is provided between the first voltage regulating circuit and the second voltage regulating circuit 1 .

5. An insulation detection method for a motor controller according to claim 4, characterized in that: The first voltage regulating circuit includes resistors R1A, R1B, and R1C connected in series; the second voltage regulating circuit includes resistors R1D and R1E connected in series; switches K1C, K1D, and K1E are respectively provided for resistors R1C, R1D, and R1E; in step S21, the DSP control board controls switches K1C, K1D, and K1E to be turned off, thereby adjusting the theoretical voltage V of the insulation detection module 11 ; in step S22, the DSP control board controls switch K1D to be turned on and controls switches K1C and K1E to be turned off, thereby adjusting the theoretical voltage V of the insulation detection module 21 .

6. An insulation detection method for a motor controller according to claim 5, characterized in that: In step S23, the DSP control board adjusts the theoretical voltage V of the insulation detection module by controlling the closing of switch K1C and switch K1D and controlling the opening of switch K1E 31 , and thereby calculates and records the insulation resistance value R under the condition of no insulation fault 31 .

7. An insulation detection method for a motor controller according to claim 1, characterized in that: the signal processing circuit includes an opto-isolation circuit, a signal amplification circuit, a filtering circuit, and a protection circuit connected in sequence.

8. An insulation detection method for a motor controller according to claim 1, characterized in that: a switch K1A is provided between the DCDC converter and the voltage regulation circuit, and the DSP control board controls the connection or disconnection of the low-voltage power supply by controlling the closing or opening of the switch K1A.

9. An insulation detection method for a motor controller according to claim 1, characterized in that: the control module further includes a current sampling board; a current transformer is provided on each of the three-phase lines of the three-phase AC motor, and the DSP control board collects the information of each current transformer through the current sampling board.

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