Insulation resistance monitoring circuit and method, air conditioner compressor and vehicle

Abstract

The invention relates to the technical field of resistance monitoring, and discloses an insulation resistance monitoring circuit and method, an air conditioner compressor and a vehicle, the circuit comprises a high-voltage power supply unit, a motor control unit, an insulation detection unit and an external high-voltage power supply, the motor control unit and the insulation detection unit are connected with the high-voltage power supply unit, and the motor control unit comprises a driving chip connected with upper and lower bridge switch tubes; controlling the motor control unit to be in a first acquisition state, a second acquisition state and a third acquisition state; the insulation detection unit comprises a resistance voltage division subunit connected with the high-voltage power supply unit; the voltage sampling subunit is connected with the resistance voltage dividing subunit and is used for acquiring a first voltage value in a first acquisition state, a second voltage value in a second acquisition state and a third voltage value in a third acquisition state; and the control chip is connected with the voltage sampling subunit and is used for monitoring insulation resistance in the high-voltage power supply unit and the motor control unit based on the first voltage value, the second voltage value and the third voltage value. The functionality of the insulation resistance monitoring circuit is improved.

Description

Technical Field

[0001] This invention relates to the field of resistance monitoring technology, and in particular to an insulation resistance monitoring circuit, method, air conditioning compressor, and vehicle. Background Technology

[0002] As high-voltage power supply units are used more and more widely, users are also putting forward higher requirements for the insulation resistance monitoring circuits in high-voltage power supply units.

[0003] Traditional insulation resistance monitoring circuits typically employ a resistor divider circuit and an isolation sampling circuit, located separately between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground (or vehicle body housing) of the high-voltage power supply unit. This allows for monitoring the insulation resistance between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground, respectively, when the high-voltage power supply unit is connected to the high-voltage power supply. However, this type of insulation resistance monitoring circuit has a significant drawback: it can only monitor the insulation resistance between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground. In other words, because it can only monitor the insulation resistance between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground, the functionality of this insulation resistance monitoring circuit is limited.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide an insulation resistance monitoring circuit, method, air conditioning compressor, and vehicle, aiming to solve the technical problem of low functionality in insulation resistance monitoring circuits.

[0006] To achieve the above objectives, the present invention provides an insulation resistance monitoring circuit, which includes a high-voltage power supply unit, a motor control unit, and an insulation detection unit. The high-voltage power supply unit is connected to the insulation detection unit, the motor control unit, and an external high-voltage power supply. The motor control unit includes:

[0007] The lower bridge switch and the upper bridge switch are respectively connected to the high-voltage power supply unit and the upper bridge switch, and the upper bridge switch is connected to the high-voltage power supply unit.

[0008] A driver chip is connected to the control terminal of the lower bridge switch and the control terminal of the upper bridge switch. The driver chip is used to control the motor control unit to be in a first acquisition state where both the upper bridge switch and the lower bridge switch are off, a second acquisition state where both the upper bridge switch and the lower bridge switch are on, and a third acquisition state where both the upper bridge switch and the lower bridge switch are off.

[0009] The insulation detection unit includes:

[0010] A voltage divider unit with a resistance, the input of which is connected to the high-voltage power supply unit;

[0011] A voltage sampling subunit, wherein the input terminal of the voltage sampling subunit is connected to the output terminal of the resistor voltage divider subunit, and the voltage sampling subunit is used to collect a first voltage value in the first sampling state, a second voltage value in the second sampling state, and a third voltage value in the third sampling state based on the resistor voltage divider subunit;

[0012] A control chip is connected to the output terminal of the voltage sampling subunit. The control chip is used to monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value and the third voltage value.

[0013] In one embodiment, the upper bridge switch includes a first switch, a second switch, and a third switch, and the lower bridge switch includes a fourth switch, a fifth switch, and a sixth switch.

[0014] The drain of the first switching transistor is connected to the drain of the second switching transistor, the drain of the third switching transistor, the positive terminal of the high-voltage power supply, and the first insulation resistor in the high-voltage power supply unit.

[0015] The source of the fourth switch is connected to the source of the fifth switch, the source of the sixth switch, the negative terminal of the high-voltage power supply, and the second insulation resistor in the high-voltage power supply unit.

[0016] The source of the first switch is connected to the drain of the fourth switch as the midpoint of the first bridge arm, the source of the second switch is connected to the drain of the fifth switch as the midpoint of the second bridge arm, and the source of the third switch is connected to the drain of the sixth switch as the midpoint of the third bridge arm.

[0017] In one embodiment, the motor control unit further includes:

[0018] A voltage sensing resistor, the second end of which is connected to the negative terminal of the high-voltage power supply, and the first end of which is connected to the midpoint of the first bridge arm, the midpoint of the second bridge arm, or the midpoint of the third bridge arm.

[0019] The third insulation resistor is connected to the external motor and the outer casing of the high-voltage power supply unit. The first input phase of the motor is connected to the midpoint of the first bridge arm, the second input phase of the motor is connected to the midpoint of the second bridge arm, and the third input phase of the motor is connected to the midpoint of the third bridge arm.

[0020] In one embodiment, the resistive voltage divider subunit includes:

[0021] Multiple voltage divider resistors are connected in sequence. The first end of the first voltage divider resistor is connected to the high-voltage power supply unit, and the second end of the last voltage divider resistor is connected to the high-voltage power supply unit. The first end of the output resistor in the voltage divider resistor is connected to the input end of the voltage sampling subunit.

[0022] In one embodiment, the high-voltage power supply unit includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground;

[0023] The high-voltage positive electrode is connected to the first terminal of the first voltage-dividing resistor in the voltage divider unit, and the outer casing ground is connected to the second terminal of the last voltage-dividing resistor in the voltage divider unit, or...

[0024] The high-voltage negative terminal is connected to the first end of the first voltage divider resistor in the voltage divider unit, and the outer casing ground is connected to the second end of the last voltage divider resistor in the voltage divider unit.

[0025] In one embodiment, the high-voltage power supply unit includes:

[0026] A first insulation resistor, the first end of which is connected to the upper bridge switch tube, the positive terminal of the high voltage power supply and the high voltage positive terminal, and the second end of which is connected to the casing ground;

[0027] The second insulation resistor has its second end connected to the lower bridge switch, the negative terminal of the high voltage power supply, and the high voltage negative terminal, and its first end connected to the housing ground.

[0028] Furthermore, to achieve the above objectives, the present invention also provides a method for monitoring the insulation resistance of an air conditioner compressor. This method is applied to the aforementioned insulation resistance monitoring circuit and includes the following steps:

[0029] The voltage values ​​collected by the voltage sampling subunit are obtained, wherein the voltage values ​​include a first voltage value of the motor control unit in a first sampling state, a second voltage value in a second sampling state, and a third voltage value in a third sampling state;

[0030] The insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit are monitored based on the first voltage value, the second voltage value, and the third voltage value.

[0031] In one embodiment, the step of monitoring the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value, and the third voltage value includes:

[0032] Determine the preset sampling ratio coefficient, the total resistance value of the resistive voltage divider subunit, the first resistance value of the voltage detection resistor in the motor control unit, and the voltage value of the high-voltage power supply;

[0033] A first current equation is established based on the first voltage value, the sampling ratio coefficient, the total resistance value, the first resistance value, and the voltage value;

[0034] A second current equation is established based on the second voltage value, the sampling scale factor, the total resistance value, and the voltage value;

[0035] A third current equation is established based on the third voltage value, the sampling ratio coefficient, the total resistance value, and the voltage value. The first current equation, the second current equation, and the third current equation are all current equations established with respect to the resistance values ​​of the first and second insulation resistors in the high-voltage power supply unit and the resistance value of the third insulation resistor in the motor control unit.

[0036] The first resistance value of the first insulation resistor, the second resistance value of the second insulation resistor, and the third resistance value of the third insulation resistor are determined based on the first current equation, the second current equation, and the third current equation.

[0037] In addition, to achieve the above objectives, the present invention also provides an air conditioning compressor, which includes a controller, a motor and a compression unit, wherein the controller is provided with an insulation resistance monitoring circuit;

[0038] The controller is connected to the motor, and the motor is connected to the compression unit;

[0039] The controller is used to perform the steps of the insulation resistance monitoring method described above.

[0040] This application also provides a vehicle, the vehicle comprising:

[0041] An air conditioning compressor, which is also used to perform the steps of the above-described insulation resistance monitoring method.

[0042] This invention provides an insulation resistance monitoring circuit. The circuit controls the motor control unit to be in a first acquisition state where both the upper and lower bridge switches are off, a second acquisition state where both the upper and lower bridge switches are off, and a third acquisition state where both the upper and lower bridge switches are on, through a driver chip. Then, based on the voltage sampling subunit, the circuit collects the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state. Finally, the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit can be monitored based on the first, second, and third voltage values. This avoids the situation in existing technologies where only the insulation resistance between the high-voltage positive electrode and the casing ground, and the insulation resistance between the high-voltage negative electrode and the casing ground, can be monitored. This insulation resistance monitoring circuit monitors resistance by acquiring the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state, thus realizing a new insulation resistance monitoring method. On the other hand, it can monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value, and the third voltage value, thereby improving the functionality of the insulation resistance monitoring circuit by monitoring the insulation resistance in the motor control unit. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of one module of the insulation resistance monitoring circuit of this application;

[0045] Figure 2 This is a schematic diagram of one module of an existing insulation resistance monitoring circuit;

[0046] Figure 3 This is a connection diagram of an existing motor control circuit;

[0047] Figure 4 A schematic diagram of a connection scenario for an existing insulation resistance monitoring circuit;

[0048] Figure 5 This is a schematic diagram of another connection scenario for an existing insulation resistance monitoring circuit;

[0049] Figure 6 This is a circuit connection diagram of the first embodiment of the insulation resistance monitoring circuit of this application;

[0050] Figure 7 This is a circuit connection diagram of the second embodiment of the insulation resistance monitoring circuit of this application;

[0051] Figure 8 This is a schematic diagram of the high-voltage acquisition in the insulation resistance monitoring circuit of this application;

[0052] Figure 9 This is a schematic diagram of the circuit connection of the voltage divider subunit in the insulation resistance monitoring circuit of this application;

[0053] Figure 10 This is a first equivalent schematic diagram of the insulation resistance monitoring circuit of this application;

[0054] Figure 11 This is a second equivalent schematic diagram of the insulation resistance monitoring circuit of this application;

[0055] Figure 12 This is a third equivalent schematic diagram of the insulation resistance monitoring circuit of this application;

[0056] Figure 13 This is a schematic diagram of the structure of an air conditioning compressor in the hardware operating environment involved in the embodiments of the present invention;

[0057] Figure 14 This is a flowchart illustrating the first embodiment of the insulation resistance monitoring method of the present invention;

[0058] Figure 15 This is a schematic diagram illustrating the implementation process of the insulation resistance monitoring method of the present invention;

[0059] Figure 16 This is a schematic diagram of the air conditioner compressor module of the present invention.

[0060] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0061] Explanation of icon numbers:

[0062] 200. High-voltage power supply; 30. Insulation detection unit; 31. Resistance voltage divider subunit; 32. Voltage sampling subunit; 33. Control chip; 10. High-voltage power supply unit; S. High-voltage switch; U DC High-voltage power supply; R P First insulation resistance; R N20. Second insulation resistance; R0. Voltage detection resistor; RX. Output resistor; R1. Voltage divider resistor; 20. Motor control unit; 21. Upper bridge switch transistor; 22. Lower bridge switch transistor; 23. Driver chip; Q1-Q6. First switch transistor-sixth switch transistor; RM. Third insulation resistance. Detailed Implementation

[0063] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0064] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0065] A commonly used insulation resistance monitoring circuit consists of a resistor divider circuit and an isolation sampling circuit installed between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground, respectively. This allows for monitoring of the insulation resistance between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground, when the high-voltage power supply is connected to the high-voltage power supply unit. (Refer to...) Figure 2 , Figure 2 This is a schematic diagram of the framework of an existing insulation resistance monitoring circuit, where R P R N These are the insulation resistances of the high-voltage positive and negative terminals to the chassis (body), respectively. By controlling the opening and closing of the two high-voltage switches S, and sampling and calculating the voltages VS1 and VS2 under various switching states, the insulation resistance R to be measured can be deduced. P and R N The resistance values ​​are used to monitor insulation resistance, where VS1 and VS2 are the voltage values ​​collected by the isolation sampling circuits when the two insulation resistors are connected individually. However, this solution can only monitor the insulation resistance between the high-voltage positive terminal and the casing ground, and the insulation resistance between the high-voltage negative terminal and the casing ground, and cannot monitor the insulation resistance in other locations, resulting in low functionality of the insulation resistance monitoring circuit. Furthermore, this solution requires two sets of switches and two sets of isolation sampling circuits to achieve the above functions, significantly increasing the required circuit area and cost, which is disadvantageous for the design of high-voltage devices such as air conditioning compressors.

[0066] Therefore, based on the shortcomings of the above insulation resistance monitoring methods, the insulation resistance monitoring circuit of this application is proposed. The main solution of the embodiment of this application is: to collect the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state through the insulation resistance monitoring circuit to perform resistance monitoring, thereby realizing a new insulation resistance monitoring method. On the other hand, the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit can be monitored based on the first voltage value, the second voltage value, and the third voltage value, thereby improving the functionality of the insulation resistance monitoring circuit by monitoring the insulation resistance in the motor control unit.

[0067] Based on this, embodiments of this application provide a control device for a parallel power module, referring to... Figure 1 , Figure 1 This is a schematic diagram of one module of the insulation resistance monitoring circuit of this application.

[0068] Reference Figure 1 This application provides an insulation resistance monitoring circuit, including a high-voltage power supply unit 10, a motor control unit 20, and an insulation detection unit 30. The high-voltage power supply unit 10 is connected to the insulation detection unit 30, the motor control unit 20, and an external high-voltage power supply 200. The motor control unit 20 includes:

[0069] The lower bridge switch tube 22 and the upper bridge switch tube 21 are respectively connected to the high voltage power supply unit 10 and the upper bridge switch tube 21, and the upper bridge switch tube 21 is connected to the high voltage power supply unit 10.

[0070] The driver chip 23 is connected to the control terminal of the lower bridge switch 22 and the control terminal of the upper bridge switch 21. The driver chip 23 is used to control the motor control unit 20 to be in a first acquisition state where both the upper bridge switch 21 and the lower bridge switch 22 are off, a second acquisition state where both the upper bridge switch 21 and the lower bridge switch 22 are off, and a third acquisition state where both the upper bridge switch 21 and the lower bridge switch 22 are on.

[0071] Insulation detection unit 30 includes:

[0072] The input terminal of the voltage divider unit 31 is connected to the high-voltage power supply unit 10.

[0073] The voltage sampling subunit 32 has its input terminal connected to the output terminal of the resistor voltage divider subunit 31. The voltage sampling subunit 32 is used to collect the first voltage value in the first sampling state, the second voltage value in the second sampling state, and the third voltage value in the third sampling state based on the resistor voltage divider subunit 31.

[0074] The control chip 33 is connected to the output terminal of the voltage sampling subunit 32. The control chip 33 is used to monitor the insulation resistance in the high voltage power supply unit 10 and the insulation resistance in the motor control unit 20 based on the first voltage value, the second voltage value and the third voltage value.

[0075] For example, for high-voltage devices containing a three-phase motor, the insulation resistance between the motor windings and the casing (hereinafter referred to as motor insulation windings) also needs to be tested. (Refer to...) Figure 3 , Figure 3 This is a connection diagram of an existing motor control circuit. RM represents the motor insulation winding (because the resistance between the three-phase windings, i.e., the internal resistance of the motor, is very small, the insulation resistance of the three-phase windings to the motor housing is shown as a single resistance in the diagram). (Refer to...) Figure 4 , Figure 4 This is a schematic diagram of a connection scenario for an existing insulation resistance monitoring circuit, specifically the entire high-voltage device containing a three-phase motor. The power switching transistors Q1 to Q6 can be either MOSFETs (Metal Oxide Semiconductor Field-Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors). Further, refer to... Figure 5 , Figure 5 This is a schematic diagram of another connection scenario for an existing insulation resistance monitoring circuit. When power switches Q1 to Q6 are off, the power switches only retain the characteristics of freewheeling diodes and are forward-biased. However, if continued use is attempted under these conditions... Figure 2 The insulation resistance monitoring method cannot detect even if the motor insulation winding RM is abnormally low, thus preventing the insulation resistance monitoring circuit from monitoring the motor insulation winding RM.

[0076] In this embodiment, to achieve insulation resistance monitoring at different locations (at least including the insulation resistance in the high-voltage power supply unit 10 and the motor control unit 20) using fewer resistor divider circuits and isolation sampling circuits, an insulation resistance monitoring circuit of this embodiment is proposed. This insulation resistance monitoring circuit uses only one set of resistor divider subunits 22 and voltage sampling subunits 23, combined with the on / off control of the switching transistors in the motor control unit 20, to monitor the insulation resistance in the high-voltage power supply unit 10 and the motor control unit 20. This reduces the cost and area occupied by the insulation resistance monitoring circuit, while also improving its functionality. (See reference...) Figure 6 , Figure 6 This is a circuit connection diagram of the first embodiment of the insulation resistance monitoring circuit of this application, combined with... Figure 6The monitoring principle of the entire insulation resistance monitoring circuit is explained as follows: The lower bridge switch 22 in the motor control unit 20 is connected to the high-voltage power supply unit 10 and the upper bridge switch 21 respectively. The upper bridge switch 21 is connected to the high-voltage power supply unit 10. That is, Q1, Q2, and Q3 in the figure are the upper bridge switch 21, and Q4, Q5, and Q6 are the lower bridge switch 22. Then, the driver chip 23 in the motor control unit 20 controls the motor control unit 20 to be in the first acquisition state where all upper bridge switches 21 are off and all lower bridge switches 22 are off (i.e., all Q1-Q6 are off), the second acquisition state where all upper bridge switches 21 are off and lower bridge switches 22 are on (i.e., all Q1-Q3 are off and at least one Q4-Q6 is on), and the third acquisition state where upper bridge switches 21 are on and lower bridge switches 22 are off (i.e., all Q4-Q6 are off and at least one Q1-Q3 is on). In other words, the driver chip 23 can control the entire insulation resistance monitoring circuit to be in three different connection states. At this point, the first voltage value, the second voltage value, and the third voltage value under three different states can be collected based on the voltage sampling subunit 32 of the insulation detection unit 30. Finally, based on the three voltage values, three sets of equations established for the three sampling states can be determined. Then, by solving the unknowns in the sets of equations, the resistance value of the insulation resistance in the high-voltage power supply unit 10 (taking the case where there are only two insulation resistances in the conventional high-voltage power supply unit 10 as an example) and the resistance value of the insulation resistance in the motor control unit 20 (taking the case where there is only one insulation resistance in the conventional motor control unit 20 as an example) can be determined.

[0077] It is worth noting that the insulation resistance in the high-voltage power supply unit 10 and the insulation resistance in the motor control unit 20 are unknowns to be solved. Other parameters in the circuit can be determined based on sampling or actual settings, such as the first voltage value, the second voltage value, the third voltage value, the resistance of the voltage divider subunit 31, and the resistance of the voltage detection resistor. Furthermore, the insulation resistance monitoring circuit can be set to the first, second, and third acquisition states solely based on the switching control of the switching transistor in the motor control unit 20. Then, the voltage sampling subunit 32 can collect the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state. Finally, three equations can be established based on the three voltage values ​​to determine whether the insulation resistance in the high-voltage power supply unit 10 and the motor control unit 20 is within the set range, thereby reducing the cost of the insulation resistance monitoring circuit. Another point is that the entire insulation resistance monitoring circuit can realize the insulation resistance detection function between the high-voltage positive and negative poles of the high-voltage power supply unit 10 and the casing, and also realize the insulation resistance detection function in the motor control unit 20.

[0078] In this embodiment, an insulation resistance monitoring circuit is provided. This circuit controls the motor control unit to be in a first acquisition state where both the upper and lower bridge switches are off, a second acquisition state where both the upper and lower bridge switches are off, and a third acquisition state where both the upper and lower bridge switches are on, through a driver chip. Then, based on the voltage sampling subunit, the circuit collects the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state. Finally, the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit can be monitored based on the first, second, and third voltage values. This avoids the situation in existing technologies where only the insulation resistance between the high-voltage positive electrode and the casing ground, and the insulation resistance between the high-voltage negative electrode and the casing ground, can be monitored. This insulation resistance monitoring circuit monitors resistance by acquiring the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state, thus realizing a new insulation resistance monitoring method. On the other hand, it can monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value, and the third voltage value, thereby improving the functionality of the insulation resistance monitoring circuit by monitoring the insulation resistance in the motor control unit.

[0079] Furthermore, based on the first embodiment of the insulation resistance monitoring circuit, a second embodiment of this application is proposed, wherein the resistance voltage divider subunit 31 includes:

[0080] Multiple voltage divider resistors R1 are connected in sequence. The first end of the first voltage divider resistor R1 is connected to the high voltage power supply unit 10, and the second end of the last voltage divider resistor R1 is connected to the high voltage power supply unit 10. The first end of the output resistor RX in the voltage divider resistor R1 is connected to the input terminal of the voltage sampling subunit 32.

[0081] In this embodiment, the voltage divider subunit 31 includes multiple voltage divider resistors R1 connected in series. One of the voltage divider resistors R1 is an output resistor RX. The first end of the output resistor RX is connected to the input terminal of the voltage sampling subunit 32 to output the sampled voltage to the voltage sampling subunit 32. The function of the voltage divider subunit 31 is to prevent the output voltage from being too large and exceeding the voltage of the voltage sampling subunit 32. If the voltage division ratio of the entire voltage divider subunit 31 is set to M, it ensures that the sampled output voltage VN does not exceed the upper limit of the voltage allowed by the voltage sampling subunit 32. It is worth noting that the sampling capability of the voltage sampling subunit 32 can also be changed to directly sample the voltage of the entire voltage divider subunit 31. If the upper limit of the voltage allowed by the voltage sampling subunit 32 is VM, to ensure that VM≥VN, consider the most extreme case: the insulation resistance of the high-voltage negative electrode is zero, i.e., R... N=0, at this time, VN = M*V DC Therefore, it is only necessary to ensure that VM ≥ M * V DC That is, select M≥V DC By using / VM, the output voltage VN can be guaranteed to not exceed the upper limit of the sampling circuit's allowed voltage, thus ensuring the accuracy of the data acquisition.

[0082] In one embodiment, reference is made to Figure 7 , Figure 7 This is a circuit connection diagram of the second embodiment of the insulation resistance monitoring circuit of this application. The entire circuit can be divided into high-voltage and low-voltage circuits. The low-voltage circuit supplies power to various components and units, such as control unit 1, the isolation communication unit, and control unit 2 and drive circuit in the high-voltage circuit. The high-voltage power supply refers to the power supply to the inverter, which in turn drives the motor, such as the voltage of a three-phase motor. The high-voltage and low-voltage circuits are separated by isolation devices. Further details can be found in... Figure 8 , Figure 8 This diagram illustrates the acquisition of high-voltage voltage in the insulation resistance monitoring circuit of this application. The voltage value of the high-voltage power supply can be stored in the control unit 2 of the high-voltage circuit via an internal resistor divider circuit and sampling circuit for later retrieval. It is worth noting that the above is only a schematic diagram of the external connection of the insulation resistance monitoring circuit; other connection diagrams are also possible. No limitation is placed on the external connection of the insulation resistance monitoring circuit here. It is worth noting that reference can be made to... Figure 9 , Figure 9 This is a circuit connection diagram of the voltage divider subunit in the insulation resistance monitoring circuit of this application. The voltage divider subunit 31 can be... Figure 9 The connection diagram can also be used for other pressure divider instruments, and is not limited here.

[0083] In one embodiment, the high-voltage power supply unit 10 includes a high-voltage positive terminal, a high-voltage negative terminal, and a housing ground;

[0084] The high-voltage positive terminal is connected to the first terminal of the first voltage-dividing resistor R1 in the voltage divider unit 31, and the outer casing ground is connected to the second terminal of the last voltage-dividing resistor R1 in the voltage divider unit 31, or...

[0085] The high-voltage negative terminal is connected to the first end of the first voltage divider resistor R1 in the voltage divider unit 31, and the outer casing ground is connected to the second end of the last voltage divider resistor R1 in the voltage divider unit 31.

[0086] Furthermore, the high-voltage power supply unit 10 includes:

[0087] First insulation resistance R P The first end of the first insulation resistor RP is connected to the positive terminal of the upper bridge switch tube 21, the high voltage power supply 200, and the high voltage positive terminal, and the second end of the first insulation resistor RP is connected to the casing ground.

[0088] The second insulation resistor RN has its second end connected to the lower bridge switch 22, the negative terminal of the high voltage power supply 200, and the high voltage negative terminal. The first end of the second insulation resistor RN is connected to the casing ground.

[0089] In this embodiment, the high-voltage power supply unit 10 includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground. That is, the resistor voltage divider subunit 31 can be connected between the high-voltage positive terminal and the casing ground, or between the high-voltage negative terminal and the casing ground. However, if it is necessary to collect the voltage value of the high-voltage negative terminal, the collected voltage can be isolated or processed as an absolute value.

[0090] Furthermore, based on the first and / or second embodiments of the insulation resistance monitoring circuit, a third embodiment of this application is proposed, wherein the upper bridge switch 21 includes a first switch Q1, a second switch Q2 and a third switch Q3, and the lower bridge switch 22 includes a fourth switch Q4, a fifth switch Q5 and a sixth switch Q6;

[0091] The drain of the first switch Q1, the drain of the second switch Q2, the drain of the third switch Q3, the positive terminal of the high-voltage power supply 200, and the first insulation resistor R in the high-voltage power supply unit 10. P connect;

[0092] The source of the fourth switch Q4, the source of the fifth switch Q5, the source of the sixth switch Q6, the negative terminal of the high-voltage power supply 200, and the second insulation resistor R in the high-voltage power supply unit 10. N connect;

[0093] The source of the first switch Q1 is connected to the drain of the fourth switch Q4 as the midpoint of the first bridge arm. The source of the second switch Q2 is connected to the drain of the fifth switch Q5 as the midpoint of the second bridge arm. The source of the third switch Q3 is connected to the drain of the sixth switch Q6 as the midpoint of the third bridge arm.

[0094] Furthermore, the motor control unit 20 also includes:

[0095] Voltage sensing resistor R0, the second end of voltage sensing resistor R0 is connected to the negative terminal of high voltage power supply 200, and the first end of voltage sensing resistor R0 is connected to the midpoint of the first bridge arm, the midpoint of the second bridge arm or the midpoint of the third bridge arm.

[0096] The third insulation resistor RM is connected to the outer casing ground of the external motor and high-voltage power supply unit 10. The first input phase of the motor is connected to the midpoint of the first bridge arm, the second input phase of the motor is connected to the midpoint of the second bridge arm, and the third input phase of the motor is connected to the midpoint of the third bridge arm.

[0097] For example, the upper bridge switch 21 includes a first switch Q1, a second switch Q2, and a third switch Q3, and the lower bridge switch 22 includes a fourth switch Q4, a fifth switch Q5, and a sixth switch Q6. Their connection method can be the same as the three-phase circuit in a commonly used three-phase motor, and is not limited here. Regarding the voltage detection resistor R0, when the air conditioner compressor (taking the high-voltage device with the insulation resistance monitoring circuit as an example) has a phase voltage sampling requirement, the existing phase voltage sampling resistor can be directly used to replace R0. This achieves both the function of R0 in insulation resistance detection and its own phase voltage sampling function. When the air conditioner compressor does not have a phase voltage sampling requirement, R0 can be directly implemented using a series resistor (ensuring its withstand voltage is sufficient). It is worth noting that the total resistance value R1 of the resistor divider circuit and the resistance value of the voltage detection resistor R0 should be selected to be relatively large, close to the order of magnitude of RP, RN, and RM, to avoid affecting the detection accuracy.

[0098] In one embodiment, when all switching transistors Q1-Q6 are off, the equivalent circuit of the entire insulation resistance monitoring circuit can be referred to Figure 10 , Figure 10 This is a first equivalent schematic diagram of the insulation resistance monitoring circuit of this application. When all switching transistors Q1-Q3 are off and at least one of Q4-Q6 is on, the equivalent circuit of the entire insulation resistance monitoring circuit can be referred to. Figure 11 , Figure 11 This is a second equivalent schematic diagram of the insulation resistance monitoring circuit of this application. When all switching transistors Q4-Q6 are off and at least one of Q1-Q3 is on, the equivalent circuit of the entire insulation resistance monitoring circuit can be referred to... Figure 12 , Figure 12 This is the third equivalent schematic diagram of the insulation resistance monitoring circuit of this application. Based on the three circuit diagrams, the current equation is established as follows:

[0099]

[0100] When power switches Q1-Q6 are closed, the first voltage value is VS0*M. When power switches Q1-Q3 are closed and at least one of Q4-Q6 is open, the second voltage value is VS1*M. When power switches Q4-Q6 are closed and at least one of Q1-Q3 is open, the third voltage value is VS4*M. RP1 is the result of the first insulation resistance RP connected in parallel with the total resistance R1 in the voltage divider unit (RP1 = RP*R1 /

[0101] (RP+R1)). Among them, VS0*M, VS1*M, VS4*M, VDC, and R0 are all known. Solving equation (1) yields a unique solution for RP1, RN, and RM, as shown in equation (2):

[0102]

[0103] Then, from equation (3), RP can be calculated:

[0104] RP = (1 / RP1 - 1 / R1) -1 (3)

[0105] This allows us to calculate the insulation resistance between the high voltage positive and negative terminals and the casing, as well as the insulation resistance between the three-phase windings of the motor and the casing, thereby improving the functionality of the insulation resistance monitoring circuit.

[0106] In yet another embodiment, reference is made to... Figure 13 , Figure 13 This is a schematic diagram of the structure of an air conditioning compressor in the hardware operating environment involved in the embodiments of the present invention.

[0107] like Figure 13 As shown, the air conditioner compressor may include: a processor 0003, such as a central processing unit (CPU), a communication bus 0001, an acquisition interface 0002, a processing interface 0004, and a memory 0005. The communication bus 0001 is used to enable communication between these components. The acquisition interface 0002 may include an information acquisition device or acquisition unit, such as a computer; optionally, the acquisition interface 0002 may also include a standard wired interface or a wireless interface. The processing interface 0004 may optionally include a standard wired interface or a wireless interface. The memory 0005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 0005 may also be a storage device independent of the aforementioned processor 0003.

[0108] Those skilled in the art will understand that Figure 13 The structure shown does not constitute a limitation on the air conditioning compressor and may include more or fewer components than illustrated, or combine certain components, or have different component arrangements. Figure 13 As shown, the memory 0005, which serves as a computer storage medium, may include an operating system, an acquisition interface module, a processing interface module, and an insulation resistance monitoring program executed by the air conditioning compressor.

[0109] exist Figure 13In the air conditioner compressor shown, the communication bus 0001 is mainly used to realize the connection and communication between components; the acquisition interface 0002 is mainly used to connect to the backend server and communicate data with the backend server; the processing interface 0004 is mainly used to connect to the deployment end (user end) and communicate data with the deployment end; the processor 0003 and the memory 0005 in the air conditioner compressor of the present invention can be set in the air conditioner compressor. The air conditioner compressor calls the insulation resistance monitoring program stored in the memory 0005 through the processor 0003 and executes the insulation resistance monitoring circuit provided in the embodiment of the present invention.

[0110] Based on the above hardware structure, an embodiment of the insulation resistance monitoring method of the present invention is proposed. In one embodiment of the present invention, as follows... Figure 13 As shown, Figure 13 This is a schematic flowchart of the insulation resistance monitoring method of the present invention. The insulation resistance monitoring method is applied to the above-mentioned insulation resistance monitoring circuit, and the insulation resistance monitoring method includes:

[0111] Step S10: Obtain the voltage value collected by the voltage sampling subunit, wherein the voltage value includes the first voltage value of the motor control unit in the first sampling state, the second voltage value in the second sampling state, and the third voltage value in the third sampling state;

[0112] In this embodiment, during insulation resistance monitoring, the voltage sampling subunit in the insulation resistance monitoring circuit collects voltage values ​​under different states. These voltage values ​​include a first voltage value in the first sampling state, a second voltage value in the second sampling state, and a third voltage value in the third sampling state. This represents different ways the motor control unit in the insulation resistance monitoring circuit controls the switching transistor to turn on and off, connecting resistors R0 and RM. After voltage division by the resistor voltage divider subunit, the voltage sampling subunit samples the voltage values ​​under the three states. These three voltage values ​​are then used to determine whether the insulation resistance in the high-voltage power supply unit and the motor control unit meets the requirements, thus achieving insulation resistance monitoring in both units. It is worth noting that insulation resistance monitoring can be performed with high voltage applied and before the motor starts operating (to avoid sampling errors caused by rapid switching of the switching transistor during motor operation), or by defining trigger conditions for monitoring; this is not limited here.

[0113] Step S20: Monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value and the third voltage value.

[0114] In this embodiment, after determining the three voltage values, the insulation resistance in the high-voltage power supply unit and the motor control unit is monitored based on these three voltage values. The main process involves establishing three equations based on the three voltage values, with only three unknowns: the resistance values ​​of the two insulation resistors in the high-voltage power supply unit and the insulation resistance value in the motor control unit. These equations and unknowns are then solved to determine the resistance values ​​of the three insulation resistors. These values ​​are then compared with preset resistance values ​​to determine if the preset resistance requirement is met. For example, if the insulation resistance value is greater than A, the user is informed that the insulation resistance monitoring result meets the requirement; otherwise, the result is determined to be unsatisfactory. The user is then prompted accordingly, or the high-voltage power supply is directly stopped to ensure power supply safety. The entire insulation resistance monitoring method is applied to an insulation resistance monitoring circuit. Through the design of the insulation resistance monitoring circuit, two sets of resistor voltage divider circuits and isolation sampling circuits are not required. Ultimately, the insulation resistance in the high-voltage power supply unit and the motor control unit can be monitored based on three voltage values, thereby reducing the cost of the insulation resistance monitoring circuit and improving its functionality.

[0115] This embodiment provides an insulation resistance monitoring method applied to an insulation resistance monitoring circuit. By controlling the motor control unit to a first acquisition state where both upper and lower bridge switches are off, a second acquisition state where both upper and lower bridge switches are off, and a third acquisition state where both upper and lower bridge switches are on, the method acquires a first voltage value in the first acquisition state, a second voltage value in the second acquisition state, and a third voltage value in the third acquisition state. Ultimately, the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit can be monitored based on the first, second, and third voltage values. This avoids the situation in existing technologies where only the insulation resistance between the high-voltage positive electrode and the casing ground, and the insulation resistance between the high-voltage negative electrode and the casing ground, can be monitored. This insulation resistance monitoring circuit monitors resistance by acquiring the first voltage value in the first acquisition state, the second voltage value in the second acquisition state, and the third voltage value in the third acquisition state, thus realizing a new insulation resistance monitoring method. On the other hand, it can monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value, and the third voltage value, thereby improving the functionality of the insulation resistance monitoring circuit by monitoring the insulation resistance in the motor control unit.

[0116] In one embodiment, based on the first embodiment of the insulation resistance monitoring method, a second embodiment of this application is proposed, comprising the steps of monitoring the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit according to a first voltage value, a second voltage value, and a third voltage value, including:

[0117] Step S21: Determine the preset sampling ratio coefficient, the total resistance value of the resistor divider subunit, the first resistance value of the voltage detection resistor in the motor control unit, and the voltage value of the high voltage power supply.

[0118] Step S22: Establish the first current equation based on the first voltage value, sampling ratio coefficient, total resistance value, first resistance value, and voltage value;

[0119] Step S23: Establish the second current equation based on the second voltage value, sampling ratio coefficient, total resistance value, and voltage value;

[0120] Step S24: Establish a third current equation based on the third voltage value, sampling ratio coefficient, total resistance value and voltage value. The first current equation, the second current equation and the third current equation are all current equations established about the resistance values ​​of the first insulation resistance and the second insulation resistance in the high voltage power supply unit and the resistance value of the third insulation resistance in the motor control unit.

[0121] Step S25: Determine the first resistance value of the first insulation resistor, the second resistance value of the second insulation resistor, and the third resistance value of the third insulation resistor based on the first current equation, the second current equation, and the third current equation.

[0122] In this embodiment, when monitoring the insulation resistance in the high-voltage power supply unit and the motor control unit, the controller will first determine the preset sampling ratio coefficient, the total resistance value of the voltage divider subunit, the first resistance value of the voltage detection resistor in the motor control unit, and the voltage value of the high-voltage power supply. The sampling ratio coefficient refers to the ratio of voltage division sampling in the voltage divider subunit, i.e., M mentioned above. The total resistance value refers to the sum of all resistances in the voltage divider subunit, i.e., R1 mentioned above. The first resistance value refers to the resistance value of the voltage detection resistor in the motor control unit, i.e., R0 mentioned above. The voltage value refers to the voltage value of the high-voltage power supply, i.e., VDC mentioned above. Combined with the three known voltages VS0, VS1, and VS4, the three formulas of formula (1) can be established, i.e., the three current equations. Finally, the unknowns RP, RN, and RM can be solved based on the three current formulas, i.e., the first resistance value of the first insulation resistance, the second resistance value of the second insulation resistance, and the third resistance value of the third insulation resistance can be determined, so as to determine whether the entire high-voltage power supply unit is safe based on the three insulation resistance values, i.e., to realize insulation resistance monitoring. Further, refer to Figure 15 , Figure 15The diagram illustrates the implementation process of the insulation resistance monitoring method of the present invention. When high voltage is detected, the monitoring process is started based on the requirement (insulation resistance monitoring requirement). The switching transistors Q1-Q6 are controlled to be in three states (first to third acquisition states), and the output voltages VS0*M, VS1*M and VS4*M of the resistive voltage divider subunit are acquired and obtained after a delay. The order of the three controls is not limited. Then, based on the output voltages VS0*M, VS1*M and VS4*M and other known quantities, the insulation resistance values ​​in the high-voltage power supply unit and the motor control unit are calculated. That is, the calculation is performed by the above formulas (1)-(3), and finally the first resistance value of the first insulation resistance, the second resistance value of the second insulation resistance and the third resistance value of the third insulation resistance are obtained. It is determined whether the three resistance values ​​are within the defined safe range (or the preset resistance value requirement mentioned above). When they are within the safe range, the communication circuit will send the sampling result to the vehicle controller (at this time, it is assumed that the insulation resistance monitoring circuit is set in the air conditioning compressor in the vehicle, or it can be in other high-voltage devices, which is not limited here). At this time, the motor enters the normal working state, that is, the motor starts normally. Conversely, when it is not within the safe range, the communication circuit will send the fault to the vehicle controller. At this time, the motor enters the fault state, that is, the motor cannot be started before the fault is cleared, so as to realize insulation resistance monitoring and ensure power supply safety.

[0123] Corresponding to the above embodiments, the present invention also proposes an air conditioning compressor.

[0124] The air conditioner compressor of this embodiment includes a controller, a motor and a compressor unit, wherein the controller is provided with an insulation resistance monitoring circuit;

[0125] The controller is connected to the motor, and the motor is connected to the compression unit;

[0126] The controller is used to perform the steps of the insulation resistance monitoring circuit described above.

[0127] According to an embodiment of the present invention, when the controller in the air conditioner compressor executes a program, the above-mentioned insulation resistance monitoring method is implemented. The method monitors the resistance by collecting a first voltage value in a first acquisition state, a second voltage value in a second acquisition state, and a third voltage value in a third acquisition state, thereby realizing a new insulation resistance monitoring method. On the other hand, the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit can be monitored based on the first voltage value, the second voltage value, and the third voltage value. By monitoring the insulation resistance in the motor control unit, the functionality of the insulation resistance monitoring circuit is improved.

[0128] The controller incorporates an insulation resistance monitoring circuit connected to the motor. This allows for the monitoring of insulation resistance in the high-voltage power supply unit and the motor control unit, ensuring safe high-voltage operation. The motor drives the compressor section to function as an air conditioning compressor. It's worth noting that the air conditioning compressor may also include other hardware, such as a housing and circuit board. The high-voltage power supply unit, motor control unit, and insulation detection unit within the insulation resistance monitoring circuit can be separately arranged on the circuit board, and the circuit board, its circuit units, and the motor can be encapsulated within the housing to form the air conditioning compressor. The controller controls the insulation resistance monitoring circuit to monitor the insulation resistance in the high-voltage power supply unit and the motor control unit, and also drives the motor control unit to control the motor. It's also worth noting that the controller can be integrated with the control chip in the insulation resistance monitoring circuit into a single controller, reducing the number of controllers required. The insulation resistance monitoring circuit can also be integrated into other high-voltage operating circuits, such as PTC (Positive Temperature Coefficient) heaters.

[0129] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0130] The vehicle in this embodiment of the invention includes an air conditioning compressor, which is used to perform the steps of the above-described insulation resistance monitoring method.

[0131] The air conditioning compressor can be installed in the vehicle. An insulation resistance monitoring method and circuit within the compressor can be used to monitor the insulation resistance in the high-voltage power supply unit and the motor control unit, thereby improving the functionality of the insulation resistance monitoring circuit. It is worth noting that other hardware can also be installed in the vehicle; these will not be detailed here. The entire air conditioning compressor can be installed in the vehicle or in other products; this is not a limitation.

[0132] The present invention also provides an air conditioning compressor, as shown in the reference. Figure 16 , Figure 16 This is a schematic diagram of an air conditioner compressor module of the present invention, wherein the air conditioner compressor includes:

[0133] The information acquisition module A01 is used to acquire the voltage value collected by the voltage sampling subunit, wherein the voltage value includes a first voltage value of the motor control unit in a first acquisition state, a second voltage value in a second acquisition state, and a third voltage value in a third acquisition state;

[0134] The resistance monitoring module A02 is used to monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value and the third voltage value.

[0135] The methods executed by the above-mentioned program modules can be referred to in the various embodiments of the optimization method of internal linkage of the present invention, and will not be repeated here.

[0136] The present invention also provides a storage medium.

[0137] The present invention stores an insulation resistance monitoring program executed by an air conditioner compressor on a storage medium. When the insulation resistance monitoring program is executed by a processor, it implements the steps of the insulation resistance monitoring circuit as described above.

[0138] The method implemented when the insulation resistance monitoring program running on the processor is executed can be referred to in various embodiments of the insulation resistance monitoring method of the present invention, and will not be repeated here.

[0139] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0140] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0141] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An insulation resistance monitoring circuit, characterized in that, The insulation resistance monitoring circuit includes a high-voltage power supply unit, a motor control unit, and an insulation detection unit. The high-voltage power supply unit is connected to the insulation detection unit, the motor control unit, and an external high-voltage power supply. The motor control unit includes: The lower bridge switch and the upper bridge switch are respectively connected to the high-voltage power supply unit and the upper bridge switch, and the upper bridge switch is connected to the high-voltage power supply unit. A driver chip is connected to the control terminal of the lower bridge switch and the control terminal of the upper bridge switch. The driver chip is used to control the motor control unit to be in a first acquisition state where both the upper bridge switch and the lower bridge switch are off, a second acquisition state where both the upper bridge switch and the lower bridge switch are on, and a third acquisition state where both the upper bridge switch and the lower bridge switch are off. The insulation detection unit includes: A voltage divider unit with a resistance, the input of which is connected to the high-voltage power supply unit; A voltage sampling subunit, wherein the input terminal of the voltage sampling subunit is connected to the output terminal of the resistor voltage divider subunit, and the voltage sampling subunit is used to collect a first voltage value in the first sampling state, a second voltage value in the second sampling state, and a third voltage value in the third sampling state based on the resistor voltage divider subunit; A control chip is connected to the output terminal of the voltage sampling subunit. The control chip is used to monitor the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value and the third voltage value.

2. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The upper bridge switch includes a first switch, a second switch, and a third switch, and the lower bridge switch includes a fourth switch, a fifth switch, and a sixth switch. The drain of the first switching transistor is connected to the drain of the second switching transistor, the drain of the third switching transistor, the positive terminal of the high-voltage power supply, and the first insulation resistor in the high-voltage power supply unit. The source of the fourth switch is connected to the source of the fifth switch, the source of the sixth switch, the negative terminal of the high-voltage power supply, and the second insulation resistor in the high-voltage power supply unit. The source of the first switch is connected to the drain of the fourth switch as the midpoint of the first bridge arm, the source of the second switch is connected to the drain of the fifth switch as the midpoint of the second bridge arm, and the source of the third switch is connected to the drain of the sixth switch as the midpoint of the third bridge arm.

3. The insulation resistance monitoring circuit as described in claim 2, characterized in that, The motor control unit also includes: A voltage sensing resistor, the second end of which is connected to the negative terminal of the high-voltage power supply, and the first end of which is connected to the midpoint of the first bridge arm, the midpoint of the second bridge arm, or the midpoint of the third bridge arm. The third insulation resistor is connected to the external motor and the outer casing of the high-voltage power supply unit. The first input phase of the motor is connected to the midpoint of the first bridge arm, the second input phase of the motor is connected to the midpoint of the second bridge arm, and the third input phase of the motor is connected to the midpoint of the third bridge arm.

4. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The resistive voltage divider subunit includes: Multiple voltage divider resistors are connected in sequence. The first end of the first voltage divider resistor is connected to the high-voltage power supply unit, and the second end of the last voltage divider resistor is connected to the high-voltage power supply unit. The first end of the output resistor in the voltage divider resistor is connected to the input end of the voltage sampling subunit.

5. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The high-voltage power supply unit includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground; The high-voltage positive electrode is connected to the first terminal of the first voltage-dividing resistor in the voltage divider unit, and the outer casing ground is connected to the second terminal of the last voltage-dividing resistor in the voltage divider unit, or... The high-voltage negative terminal is connected to the first end of the first voltage divider resistor in the voltage divider unit, and the outer casing ground is connected to the second end of the last voltage divider resistor in the voltage divider unit.

6. The insulation resistance monitoring circuit as described in claim 5, characterized in that, The high-voltage power supply unit includes: A first insulation resistor, the first end of which is connected to the upper bridge switch transistor, the positive terminal of the high voltage power supply and the high voltage positive terminal, and the second end of which is connected to the ground of the casing; The second insulation resistor has its second end connected to the lower bridge switch, the negative terminal of the high voltage power supply, and the high voltage negative terminal, and its first end connected to the housing ground.

7. A method for monitoring insulation resistance, characterized in that, The insulation resistance monitoring method is applied to the insulation resistance monitoring circuit as described in any one of claims 1 to 6, and the insulation resistance monitoring method includes the following steps: The voltage values ​​collected by the voltage sampling subunit are obtained, wherein the voltage values ​​include a first voltage value of the motor control unit in a first sampling state, a second voltage value in a second sampling state, and a third voltage value in a third sampling state; The insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit are monitored based on the first voltage value, the second voltage value, and the third voltage value.

8. The insulation resistance monitoring method as described in claim 7, characterized in that, The step of monitoring the insulation resistance in the high-voltage power supply unit and the insulation resistance in the motor control unit based on the first voltage value, the second voltage value, and the third voltage value includes: Determine the preset sampling ratio coefficient, the total resistance value of the resistive voltage divider subunit, the first resistance value of the voltage detection resistor in the motor control unit, and the voltage value of the high-voltage power supply; A first current equation is established based on the first voltage value, the sampling ratio coefficient, the total resistance value, the first resistance value, and the voltage value; A second current equation is established based on the second voltage value, the sampling scale factor, the total resistance value, and the voltage value; A third current equation is established based on the third voltage value, the sampling ratio coefficient, the total resistance value, and the voltage value. The first current equation, the second current equation, and the third current equation are all current equations established with respect to the resistance values ​​of the first and second insulation resistors in the high-voltage power supply unit and the resistance value of the third insulation resistor in the motor control unit. The first resistance value of the first insulation resistor, the second resistance value of the second insulation resistor, and the third resistance value of the third insulation resistor are determined based on the first current equation, the second current equation, and the third current equation.

9. An air conditioning compressor, characterized in that, The air conditioning compressor includes a controller, a motor, and a compressor unit, wherein the controller is provided with an insulation resistance monitoring circuit as described in any one of claims 1 to 6; The controller is connected to the motor, and the motor is connected to the compression unit; The controller is used to perform the steps of the insulation resistance monitoring method as described in any one of claims 7 to 8.

10. A vehicle, characterized in that, The vehicle includes an air conditioning compressor, which is used to perform the steps of the insulation resistance monitoring method as described in any one of claims 7 to 8.

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