Insulation resistance monitoring circuit, air conditioner compressor and vehicle

Abstract

The application discloses an insulation resistance monitoring circuit, an air conditioner compressor and a vehicle, relates to the technical field of resistance monitoring, and discloses an insulation resistance monitoring circuit, which comprises an isolation voltage source, an input end of the isolation voltage source is connected with an external low-voltage power supply, and an output end of the isolation voltage source is connected with a high-voltage power supply unit; an isolated sampling subunit, an input end of the isolated sampling subunit is connected with the high-voltage power supply unit; and a control chip, which is connected with an output end of the isolated sampling subunit and a control end of the isolation voltage source, wherein a voltage value after energy storage capacitors in the high-voltage power supply unit stop charging is collected by the isolated sampling subunit and transmitted to the control chip, and the control chip monitors insulation resistance in the high-voltage power supply unit based on the voltage value and a collection time length corresponding to the voltage value. The application realizes insulation resistance monitoring on the premise that the high-voltage power supply is not connected with the high-voltage power supply unit for power-on.

Description

Technical Field

[0001] This application relates to the field of resistance monitoring technology, and in particular to an insulation resistance monitoring circuit, an air conditioning compressor, and a 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 consist 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 (vehicle body housing), 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. However, this 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, when the high-voltage power supply is connected to the high-voltage power supply unit. Therefore, a new insulation resistance monitoring circuit is urgently needed that can monitor insulation resistance without relying on the connection of the high-voltage power supply to the high-voltage power supply unit.

[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. Utility Model Content

[0005] The main purpose of this application is to provide an insulation resistance monitoring circuit, an air conditioning compressor, and a vehicle, aiming to solve the technical problem of how to achieve insulation resistance monitoring without relying on a high-voltage power supply and a high-voltage power supply unit for power connection.

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

[0007] An isolated voltage source, the input terminal of which is connected to an external low-voltage power supply, and the output terminal of which is connected to the high-voltage power supply unit;

[0008] An isolation sampling subunit, the input terminal of which is connected to the high-voltage power supply unit;

[0009] A control chip is connected to the output terminal of the isolation sampling subunit and the control terminal of the isolation voltage source. The voltage value of the energy storage capacitor in the high-voltage power supply unit after charging stops is collected by the isolation sampling subunit and transmitted to the control chip. The control chip monitors the insulation resistance in the high-voltage power supply unit based on the voltage value and the corresponding acquisition time.

[0010] In one embodiment, the insulation resistance monitoring circuit further includes:

[0011] A control switch is connected to the output terminal of the isolation voltage source and the high-voltage power supply unit. The control switch is used to control the isolation voltage source to charge or stop charging the energy storage capacitor in the high-voltage power supply unit.

[0012] In one embodiment, the isolated voltage source includes:

[0013] An isolation voltage controller, wherein the control terminal of the isolation voltage controller is connected to the control chip, and the input terminal of the isolation voltage controller is connected to the low-voltage power supply;

[0014] An isolation transformer, wherein the primary winding of the isolation transformer is connected to the output terminal of the isolation voltage controller, the primary winding is wound on the transformer core of the isolation transformer, and the first end of the secondary winding of the isolation transformer is connected to the high-voltage power supply unit;

[0015] A diode, wherein the anode of the diode is connected to the second end of the secondary coil, and the cathode of the diode is connected to the high-voltage power supply unit.

[0016] In one embodiment, the high-voltage power supply unit includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground;

[0017] The first end of the secondary coil is connected to the high-voltage positive terminal, and the cathode of the diode is connected to the ground of the housing, or...

[0018] The first end of the secondary coil is connected to the high-voltage negative terminal, and the cathode of the diode is connected to the ground of the housing, or...

[0019] The first end of the secondary coil is connected to the outer casing ground, and the cathode of the diode is connected to the high-voltage positive terminal, or...

[0020] The first end of the secondary coil is connected to the outer casing ground, and the cathode of the diode is connected to the high-voltage negative terminal.

[0021] In one embodiment, the isolated sampling subunit includes an isolated sampling operational amplifier, which includes a positive sampling terminal and a negative sampling terminal;

[0022] The positive sampling terminal is connected to the first end of the secondary coil, and the negative sampling terminal is connected to the cathode of the diode, or...

[0023] The negative sampling terminal is connected to the first end of the secondary coil, and the positive sampling terminal is connected to the cathode of the diode.

[0024] In one embodiment, the high-voltage power supply unit includes:

[0025] A first energy storage capacitor, the first end of which is connected to the high voltage positive terminal of the high voltage power supply unit, and the second end of which is connected to the ground of the outer casing of the high voltage power supply unit.

[0026] The second energy storage capacitor has its second terminal connected to the high-voltage negative terminal of the high-voltage power supply unit, and its first terminal connected to the ground of the outer casing.

[0027] A first insulation resistor, the first end of which is connected to the high voltage positive electrode, and the second end of which is connected to the ground of the outer casing;

[0028] The second insulation resistor has its second end connected to the high voltage negative electrode and its first end connected to the outer casing ground.

[0029] In one embodiment, the high-voltage power supply unit further includes:

[0030] A filter capacitor, wherein the first end of the filter capacitor is connected to the high voltage positive terminal of the high voltage power supply unit, and the second end of the filter capacitor is connected to the high voltage negative terminal of the high voltage power supply unit;

[0031] The bus resistor has its first end connected to the high-voltage positive terminal of the high-voltage power supply unit, and its second end connected to the high-voltage negative terminal of the high-voltage power supply unit.

[0032] In one embodiment, the isolated sampling subunit includes a first isolated sampling subunit and a second isolated sampling subunit;

[0033] The first isolated sampling subunit is connected to the high-voltage positive terminal of the high-voltage power supply unit and the ground of the high-voltage power supply unit's casing;

[0034] The second isolation sampling subunit is connected to the high-voltage negative terminal of the high-voltage power supply unit and the ground of the high-voltage power supply unit.

[0035] In addition, to achieve the above objectives, an air conditioning compressor is also provided, which includes a controller, a motor and a compression unit, wherein the controller is connected to the motor and the motor is connected to the compression unit, and the controller is provided with an insulation resistance monitoring circuit as described above.

[0036] In addition, to achieve the above objectives, a vehicle is also provided, the vehicle including the aforementioned air conditioning compressor.

[0037] This application provides an insulation resistance monitoring circuit, including a high-voltage power supply unit and an insulation detection unit. The insulation detection unit is connected to the high-voltage power supply unit and includes: an isolation voltage source, the input of which is connected to an external low-voltage power supply, and the output of which is connected to the high-voltage power supply unit; an isolation sampling subunit, the input of which is connected to the high-voltage power supply unit; and a control chip, the output of which is connected to the control terminal of the isolation sampling subunit and the isolation voltage source. The voltage value of the energy storage capacitor in the high-voltage power supply unit after charging stops is collected by the isolation sampling subunit and transmitted to the control chip. The control chip monitors the insulation resistance in the high-voltage power supply unit based on the voltage value and the corresponding sampling duration. This insulation resistance monitoring circuit uses the isolation voltage source and a low-voltage power supply to charge the energy storage capacitor in the high-voltage power supply unit to a first voltage level. The system simultaneously acquires the first capacitor voltage under the first state based on the isolation sampling subunit, and then controls the isolation voltage source to stop charging the energy storage capacitor when it reaches the first state based on the control chip. At a preset time threshold, it acquires the second capacitor voltage of the energy storage capacitor. Finally, the insulation resistance in the high-voltage power supply unit can be monitored based on the second capacitor voltage, the first capacitor voltage, and the preset time threshold. That is, the insulation resistance value in the high-voltage power supply unit is determined based on the two voltages (the second capacitor voltage and the first capacitor voltage) and the time (the preset time threshold). This avoids the phenomenon that the insulation resistance between the high-voltage positive terminal and the casing ground and the high-voltage negative terminal and the casing ground can only be monitored when the high-voltage power supply and the high-voltage power supply unit are connected and powered on. By monitoring the insulation resistance in the high-voltage power supply unit using the second capacitor voltage, the first capacitor voltage, and the preset time threshold, insulation resistance monitoring can be achieved without relying on the connection of the high-voltage power supply and the high-voltage power supply unit. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the first embodiment of the insulation resistance monitoring circuit of this application;

[0039] Figure 2 A schematic diagram of the existing insulation resistance monitoring circuit.

[0040] Figure 3 This is a schematic diagram of a high-voltage power supply unit in the insulation resistance monitoring circuit of this application.

[0041] Figure 4 This is a connection diagram of the insulation detection unit in the insulation resistance monitoring circuit of this application;

[0042] Figure 5 This is a connection diagram of the first embodiment of the isolation voltage source in the insulation resistance monitoring circuit of this application;

[0043] Figure 6 This is a connection diagram of the second embodiment of the isolation voltage source in the insulation resistance monitoring circuit of this application;

[0044] Figure 7 This is a connection diagram of the third embodiment of the isolation voltage source in the insulation resistance monitoring circuit of this application;

[0045] Figure 8 This is a connection diagram of the first embodiment of the insulation resistance monitoring circuit of this application;

[0046] Figure 9 This is a connection diagram of the second embodiment of the insulation resistance monitoring circuit of this application;

[0047] Figure 10 This is a connection diagram of the third embodiment of the insulation resistance monitoring circuit of this application;

[0048] Figure 11 This is an equivalent connection diagram of the insulation resistance monitoring circuit of this application;

[0049] Figure 12 This is a flowchart illustrating the insulation resistance monitoring method of this application;

[0050] Figure 13 This is a connection diagram of the fourth embodiment of the insulation resistance monitoring circuit of this application;

[0051] Figure 14 This is a connection diagram of the fifth embodiment of the insulation resistance monitoring circuit of this application;

[0052] Figure 15 This is another equivalent connection diagram of the insulation resistance monitoring circuit of this application.

[0053] 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.

[0054] Explanation of icon numbers:

[0055] 200. Low-voltage power supply; 10. Insulation detection unit; 11. Isolation voltage source; 12. Isolation sampling subunit; 13. Control chip; 20. High-voltage power supply unit; S. High-voltage switch; UDC High-voltage power supply; R P First insulation resistance; R N Second insulation resistance; R P N, bus resistance; C P First energy storage capacitor; C N Second energy storage capacitor; C X 1. Filter capacitor; D. Diode; C. Energy storage capacitor; 1A. Isolation voltage controller; 1B. Isolation transformer; S1. Control switch; X. Transformer core; Q1. Primary coil; Q2. Secondary coil. Detailed Implementation

[0056] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0057] 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.

[0058] 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 the insulation resistance, where VS1 and VS2 are the voltage values ​​collected by the isolation sampling circuits of each insulation resistor when they are connected individually. However, the above scheme can only realize insulation resistance detection when the high voltage is on. When the high voltage is off (U in the figure), the insulation resistance is not detected. DC When a branch circuit is disconnected, the circuit cannot perform insulation resistance detection, which means that the insulation resistance cannot be detected before high voltage is applied. However, if system insulation failure has already occurred before high voltage is applied, applying high voltage first and then detecting it will still pose a safety hazard to the system.

[0059] Therefore, based on the shortcomings of the above-mentioned safety upgrade methods for insulation resistance monitoring circuits, this application proposes an insulation resistance monitoring circuit: An isolated voltage source is used to charge the energy storage capacitor in the high-voltage power supply unit to a first state using a low-voltage power supply. Simultaneously, an isolated sampling subunit collects the first capacitor voltage in the first state. A control chip then controls the isolated voltage source to stop charging the energy storage capacitor when it reaches the first state, and acquires the second capacitor voltage at a preset time threshold. Finally, the insulation resistance in the high-voltage power supply unit can be monitored based on the second capacitor voltage, the first capacitor voltage, and the preset time threshold. That is, the insulation resistance value in the high-voltage power supply unit is determined based on the two voltages (the second capacitor voltage and the first capacitor voltage) and the time (the preset time threshold). This avoids the phenomenon that 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 can only be monitored when the high-voltage power supply and the high-voltage power supply unit are connected and powered on. By monitoring the insulation resistance in the high-voltage power supply unit using the second capacitor voltage, the first capacitor voltage, and the preset time threshold, insulation resistance monitoring can be achieved without relying on the connection of the high-voltage power supply and the high-voltage power supply unit.

[0060] Based on this, the embodiments of this application provide an insulation resistance monitoring circuit, referring to... Figure 1 , Figure 1 This is a schematic diagram of the first embodiment of the insulation resistance monitoring circuit of this application.

[0061] Reference Figure 1 This application provides an insulation resistance monitoring circuit 200, which includes a high-voltage power supply unit 20 and an insulation detection unit 10. The insulation detection unit 10 is connected to the high-voltage power supply unit 20 and includes:

[0062] An isolation voltage source 11 is provided, with its input terminal connected to an external low-voltage power supply 200 and its output terminal connected to a high-voltage power supply unit 20.

[0063] The isolation sampling subunit 12 is connected to the high-voltage power supply unit 20 at its input terminal.

[0064] The control chip 13 is connected to the output terminal of the isolation sampling subunit 12 and the control terminal of the isolation voltage source 11. The voltage value of the energy storage capacitor C in the high voltage power supply unit 20 after charging stops is collected by the isolation sampling subunit 12 and transmitted to the control chip 13. The control chip 13 monitors the insulation resistance in the high voltage power supply unit 20 based on the voltage value and the corresponding acquisition time.

[0065] In one embodiment, the insulation resistance monitoring circuit further includes:

[0066] Control switch S1 is connected to the output terminal of isolation voltage source 11 and high voltage power supply unit 20. Control switch S1 is used to control the isolation voltage source 22 to charge or stop charging the energy storage capacitor C in high voltage power supply unit 30.

[0067] For example, refer to Figure 3 , Figure 3 This is a schematic diagram of a high-voltage power supply unit in the insulation resistance monitoring circuit of this application. The high-voltage voltage in the high-voltage power supply unit and the low-voltage voltage in the system (such as the adjustable compressor system using the insulation resistance monitoring circuit of this embodiment) are independent voltages, do not share a common ground, and can operate at different times. Figure 3 As shown, R P and R N These are the insulation resistances of the high-voltage positive and negative terminals to the casing, distributed between the high-voltage positive and negative terminals and the casing. The high-voltage power supply unit also has a first energy storage capacitor C. P Second energy storage capacitor C N The first energy storage capacitor C P With the first insulation resistance R P Parallel connection, second energy storage capacitor C N With the second insulation resistance R N It is connected in parallel, and has a filter capacitor C between the positive and negative high voltage terminals. X and bus resistance R P N, filter capacitor C X and bus resistance R P N are connected in parallel, and the entire circuit is also connected to a three-phase inverter circuit to control the motor in the three-phase inverter circuit. Among them, the filter capacitor C... X Its function in the circuit is to provide support and voltage regulation for the inverter circuit, and to act as an EMC (Electromagnetic Compatibility) filter. The first energy storage capacitor C P Second energy storage capacitor C N Its function in the circuit is EMC filtering, and in this embodiment, it also serves as the energy storage capacitor C and the bus resistor R. P N is the total impedance of the high-voltage bus within the component. This may include discharge resistors, bus voltage sampling resistors, etc. The discharge resistor acts as a filter capacitor C in the circuit. X Provide a charge discharge path to ensure the filter capacitor C is properly positioned after a high-voltage power outage. X The stored voltage can be discharged relatively quickly. The function of the bus voltage sampling resistor in the circuit is to divide the high-voltage bus voltage proportionally to a lower amplitude before sampling.

[0068] In this embodiment, based on the high-voltage power supply unit 20, the composition of the insulation detection unit 10 is proposed, which can be referred to as follows. Figure 1The block diagram shows that the insulation detection unit 10 includes an isolation voltage source 11, an isolation sampling subunit 12, and a control chip 13. At this time, based on an external low-voltage power supply 200, the isolation voltage source 11 can supply power to the energy storage capacitor C (which can be the first energy storage capacitor C) in the high-voltage power supply unit 20. P Or the second energy storage capacitor C N At this point, insulation resistance monitoring is achieved based on the low-voltage power supply 200, which operates independently of the high-voltage power supply, to avoid the problem of monitoring insulation resistance only after each high-voltage power-on. The energy storage capacitor C can then be charged to the first state, and the first capacitor voltage in the first state can be collected by the isolation sampling subunit 12. This allows the determination of the charging termination voltage of the energy storage capacitor C. The first state refers to a user-defined state, such as a fully charged capacitor, and the first capacitor voltage refers to the voltage value collected in this first state. Based on the characteristics of the capacitor, the internal circuit can then be discharged. Specifically, the control chip 13 controls the isolation voltage source 11 to stop charging when the energy storage capacitor C is charged to the first state. Because of the internal insulation resistance, the insulation resistance consumes the charge inside the energy storage capacitor C. Since there is a discharge relationship in the RC circuit, the second capacitor voltage of the energy storage capacitor C collected by the isolation sampling subunit 12 can be obtained after a preset time threshold after charging stops. Based on the discharge start voltage (first capacitor voltage), discharge termination voltage (second capacitor voltage), and the preset time threshold, the resistance value of the insulation resistance in the RC circuit can be determined, thereby enabling the monitoring of the insulation resistance in the high-voltage power supply unit 20. It is worth noting that after the energy storage capacitor C is fully charged (the output of the isolation voltage source 11 is no longer supplying power to the high-voltage power supply unit 20), voltage values ​​can be arbitrarily collected at two time points (to avoid the time point being as close as possible to the time point of charging completion). The interval between these two time points can then be determined, and based on the two voltage values ​​and the time interval, the insulation resistance value in the high-voltage power supply unit 20 can be determined using a commonly used discharge formula, thus enabling insulation resistance monitoring in the high-voltage power supply unit 20. The discharge relationship of a capacitor in an RC circuit is a commonly used discharge formula; therefore, insulation resistance monitoring can be achieved simply by modifying the circuit without relying on a high-voltage power supply and a connection to the high-voltage power supply unit.

[0069] In one embodiment, in addition to controlling the isolation voltage source 11 to stop charging based on the control chip 13, such as the controller inside the isolation voltage source 11 disconnecting from the input or output, the start or stop of charging can also be controlled based on the control switch S1. For example, the control switch S1 can be a relay, a high-voltage MOSFET, etc., so that the energy storage capacitor C in the high-voltage power supply unit 30 can be charged or stopped by the control chip 13 or other control chips. At the same time, in order to avoid damage caused by high voltage, the selection of the control switch S1 should also pay attention to selecting a sufficient voltage rating.

[0070] In this embodiment, an insulation resistance monitoring circuit is provided, including a high-voltage power supply unit and an insulation detection unit. The insulation detection unit is connected to the high-voltage power supply unit and includes: an isolation voltage source, the input terminal of which is connected to an external low-voltage power supply, and the output terminal of which is connected to the high-voltage power supply unit; an isolation sampling subunit, the input terminal of which is connected to the high-voltage power supply unit; and a control chip, the control chip being connected to the output terminal of the isolation sampling subunit and the control terminal of the isolation voltage source. The voltage value of the energy storage capacitor in the high-voltage power supply unit after charging stops is collected by the isolation sampling subunit and transmitted to the control chip. The control chip monitors the insulation resistance in the high-voltage power supply unit based on the voltage value and the corresponding sampling duration. This insulation resistance monitoring circuit uses a low-voltage power supply to charge the energy storage capacitor in the high-voltage power supply unit to a specified value using an isolation voltage source. In one state, the first capacitor voltage in the first state is collected by the isolation sampling subunit. Then, the isolation voltage source is controlled by the control chip to stop charging the energy storage capacitor when it reaches the first state. The second capacitor voltage of the energy storage capacitor is obtained at a preset time threshold. Finally, the insulation resistance in the high-voltage power supply unit can be monitored based on the second capacitor voltage, the first capacitor voltage, and the preset time threshold. That is, the insulation resistance in the high-voltage power supply unit is determined based on the two voltages (the second capacitor voltage and the first capacitor voltage) and the time (the preset time threshold). This avoids the phenomenon that 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 can only be monitored when the high-voltage power supply is connected to the high-voltage power supply unit. By monitoring the insulation resistance in the high-voltage power supply unit through the second capacitor voltage, the first capacitor voltage, and the preset time threshold, insulation resistance monitoring can be achieved without relying on the high-voltage power supply being connected to the high-voltage power supply unit.

[0071] Furthermore, based on the first embodiment of this application described above, a second embodiment of the insulation resistance monitoring circuit of this application is proposed, with reference to... Figure 4 , Figure 4 This is a connection diagram of the insulation detection unit in the insulation resistance monitoring circuit of this application. The isolation voltage source 11 includes:

[0072] The isolation voltage controller 1A has its control terminal connected to the control chip 13 and its input terminal connected to the low-voltage power supply 200.

[0073] Isolation transformer 1B, the primary coil Q1 in isolation transformer 1B is connected to the output terminal of isolation voltage controller 1A, the primary coil Q1 is wound on the transformer core X in isolation transformer 1B, and the first end of the secondary coil Q2 in isolation transformer 1B is connected to high voltage power supply unit 20.

[0074] Diode D has its anode connected to the second terminal of the secondary coil Q2, and its cathode connected to the high-voltage power supply unit 20.

[0075] For example, the isolation voltage source 11 comprises an isolation voltage controller 1A, an isolation transformer 1B, and a diode D, thereby enabling the charging of the energy storage capacitor C in the high-voltage power supply unit 20. The isolation voltage controller 1A can be connected to the control chip 13 to control the entire isolation voltage source 11 to start or stop charging. After charging the energy storage capacitor C in the high-voltage power supply unit 20 based on the isolation voltage source 11, the voltage at the start of discharge, the voltage at the end of discharge, and the discharge duration are collected by the isolation sampling subunit 12 to determine the insulation resistance value in the high-voltage power supply unit 20, thus enabling the monitoring of the insulation resistance in the high-voltage power supply unit 20. It is worth noting that the insulation detection circuit is powered directly or indirectly by a low-voltage voltage, and its power supply does not depend on the high-voltage voltage; therefore, this circuit can operate even when the high voltage is not energized.

[0076] In one embodiment, the high-voltage power supply unit 20 includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground;

[0077] The first terminal of the secondary coil Q2 is connected to the high-voltage positive terminal, and the cathode of diode D is connected to the casing ground, or...

[0078] The first terminal of the secondary coil Q2 is connected to the high-voltage negative terminal, and the cathode D of the diode is connected to the casing ground, or...

[0079] The first terminal of the secondary coil Q2 is connected to the casing ground, and the cathode of diode D is connected to the high-voltage positive terminal, or...

[0080] The first end of the secondary coil Q2 is connected to the casing ground, and the cathode of diode D is connected to the high voltage negative terminal.

[0081] In one embodiment, the isolated sampling subunit 12 includes an isolated sampling operational amplifier, which includes a positive sampling terminal and a negative sampling terminal;

[0082] The positive sampling terminal is connected to the first end of the secondary coil Q2, and the negative sampling terminal is connected to the cathode of diode D, or...

[0083] The negative sampling terminal is connected to the first end of the secondary coil Q2, and the positive sampling terminal is connected to the cathode of diode D.

[0084] In this embodiment, the high-voltage power supply unit 20 includes a high-voltage positive terminal, a high-voltage negative terminal, and a casing ground. Specifically, the high-voltage positive terminal is the end connected to the positive terminal of the high-voltage power supply, the high-voltage negative terminal is the end connected to the negative terminal of the high-voltage power supply, and the casing ground refers to the vehicle's casing ground. Since there are capacitors that can act as energy storage capacitors and insulation resistance that needs to be monitored between the high-voltage positive terminal and the casing ground, and between the high-voltage negative terminal and the casing ground, the isolation voltage source 11 can be connected between the high-voltage positive terminal and the casing ground, or between the high-voltage negative terminal and the casing ground, and there are no requirements regarding the positive or negative terminals of the isolation voltage source 11. (See reference...) Figure 5 , Figure 5 This is a schematic diagram of the connection of the isolation voltage source in the insulation resistance monitoring circuit of this application. In the diagram, the isolation voltage source 11 is connected between the high voltage positive terminal and the casing ground, and the positive terminal of the isolation voltage source 11 is connected to the high voltage positive terminal. The control switch S1 is connected between the negative terminal of the isolation voltage source 11 and the casing ground. (See reference...) Figure 6 , Figure 6 This is a schematic diagram of the connection of the isolation voltage source in the insulation resistance monitoring circuit of this application, in which the isolation voltage source 11 is connected between the high voltage positive terminal and the casing ground, and the negative terminal of the isolation voltage source 11 is connected to the high voltage positive terminal. The control switch S1 is connected between the positive terminal of the isolation voltage source 11 and the casing ground; see reference. Figure 7 , Figure 7 This is a schematic diagram of the connection of the isolation voltage source in the insulation resistance monitoring circuit of this application in a third embodiment. In the diagram, the isolation voltage source 11 is connected between the high voltage negative terminal and the casing ground, and the negative terminal of the isolation voltage source 11 is connected to the casing ground. The control switch S1 is connected between the negative terminal of the isolation voltage source 11 and the high voltage negative terminal. The above are only some feasible embodiments of this embodiment, and other connection methods are also possible, which are not limited here.

[0085] In one embodiment, the isolation sampling subunit 12 includes an isolation sampling operational amplifier, which is a commonly used chip for collecting voltage values; no specific chip model is limited here. The isolation sampling operational amplifier can have the same positive and negative terminals as the isolation voltage source 11. That is, the positive terminal of the isolation voltage source 11 is connected to the positive sampling terminal of the isolation sampling operational amplifier, and the negative terminal of the isolation voltage source 11 is connected to the negative sampling terminal of the isolation sampling operational amplifier. In this case, the sampled voltage is positive. Conversely, if the positive terminal of the isolation voltage source 11 is connected to the negative sampling terminal of the isolation sampling operational amplifier, and the negative terminal of the isolation voltage source 11 is connected to the positive sampling terminal of the isolation sampling operational amplifier, the sampled voltage is also positive. This allows for the subsequent processing of the collected values ​​by performing absolute value processing to obtain the required value. Based on the two collected values ​​(the second capacitor voltage and the first capacitor voltage) and the time difference between the two collected values ​​(a preset time threshold), the insulation resistance in the high-voltage power supply unit can be monitored. This allows insulation resistance monitoring to be achieved without relying on the connection of the high-voltage power supply to the high-voltage power supply unit.

[0086] Furthermore, based on the first and / or second embodiments of this application described above, a third embodiment of the insulation resistance monitoring circuit of this application is proposed, with reference to... Figure 8 , Figure 8 This is a connection diagram of the first embodiment of the insulation resistance monitoring circuit of this application (the mountain-shaped symbol in the diagram represents the casing). The high-voltage power supply unit 20 includes:

[0087] First energy storage capacitor C P The first energy storage capacitor C P The first terminal is connected to the high-voltage positive terminal of the high-voltage power supply unit 20, and the first energy storage capacitor C P The second end is connected to the ground of the high-voltage power supply unit's casing;

[0088] Second energy storage capacitor C N The second energy storage capacitor C N The second terminal is connected to the high-voltage negative terminal of the high-voltage power supply unit 20, and the second energy storage capacitor C N The first end is connected to the outer casing;

[0089] First insulation resistance R P First insulation resistance R P The first terminal is connected to the high-voltage positive terminal, and the first insulation resistance R P The second end is connected to the outer casing;

[0090] Second insulation resistance R N Second insulation resistance R N The second terminal is connected to the high-voltage negative electrode, and the second insulation resistance R N The first end is connected to the outer shell.

[0091] In one embodiment, the high-voltage power supply unit 20 further includes:

[0092] Filter capacitor C X Filter capacitor C X The first terminal is connected to the high-voltage positive terminal of the high-voltage power supply unit 20, and the filter capacitor C X The second end is connected to the high-voltage negative terminal of the high-voltage power supply unit 20;

[0093] Bus resistance R P N, bus resistance R P The first terminal of N is connected to the high-voltage positive terminal of the high-voltage power supply unit 20, and the bus resistance R P The second terminal of N is connected to the high-voltage negative terminal of the high-voltage power supply unit 20.

[0094] In this embodiment, the high-voltage power supply unit 20 consists of the above circuitry, primarily for monitoring the first insulation resistance R. P Second insulation resistance R NThe resistance value is then used to determine whether the resistance values ​​of the two resistors meet the insulation resistance requirements. For example... Figure 8 As shown, a control switch S1 can be used to control the isolation voltage source 11 to start or stop charging the energy storage capacitor C in the high-voltage power supply unit 20. The energy storage capacitor C in the figure refers to the first energy storage capacitor C. P For reference Figure 9 , Figure 9 This is a connection diagram of the second embodiment of the insulation resistance monitoring circuit of this application. Two control switches S1 can be used to control the isolation voltage source 11 to start or stop charging the energy storage capacitor C in the high-voltage power supply unit 20. The energy storage capacitor C in the figure refers to the first energy storage capacitor C. P For reference Figure 10 , Figure 10 This is a connection diagram of the third embodiment of the insulation resistance monitoring circuit of this application. In this case, the voltage value collected by the isolation sampling subunit 12 can be transmitted to the control chip 13 so that the control chip 13 can monitor the first insulation resistance R. P Second insulation resistance R N The resistance value is monitored. Furthermore, the internal composition of the high-voltage power supply unit 20 is analyzed, because the filter capacitor C... X The impedance compared to the first energy storage capacitor C P Or the first insulation resistance R P Negligible resistance R between positive and negative terminals P The impedance of N compared to the first insulation resistance R P Or the second insulation resistance R N Negligible and for the first insulation resistance R P Second insulation resistance R N When the parallel resistance value is detected, the following can be obtained: Figure 11 Equivalent diagram. Figure 11 This is an equivalent connection diagram of the insulation resistance monitoring circuit of this application, namely the bus resistance R. P N and filter capacitor C X This is directly equivalent to a wire, resulting in an equivalent circuit where the insulation resistance and energy storage capacitor are connected in parallel. Based on this equivalent circuit, the first insulation resistance R is then determined. P Second insulation resistance R N The resistance value is used to monitor the insulation resistance.

[0095] In one embodiment, the entire referenceable Figure 12 , Figure 12 This is a flowchart illustrating the insulation resistance monitoring method of this application. When the high-voltage switch S is open (high voltage is not energized), the control switch S1 is closed and the isolation voltage source output is controlled to... Figure 8 For example, at this time, the isolation voltage source supplies power to the first energy storage capacitor C. PCharging, and real-time sampling of the first energy storage capacitor C through the isolation sampling subunit 12. P The voltage of the first energy storage capacitor C is detected to confirm its functionality. P Once the voltage on the circuit reaches the preset voltage, the control switch S1 is disconnected (or the output of the isolation voltage source can be stopped). After a delay of a certain duration, the first energy storage capacitor C is sampled again through the isolation sampling subunit 12. P The voltage is detected by the first energy storage capacitor C. P The discharge rate of the applied voltage is used to calculate whether the system insulation resistance is normal, and then the result is sent to the vehicle controller via a communication circuit, such as a wireless communication device. This is because, under normal circumstances, in high-voltage components including the air conditioning compressor and PTC (Positive Temperature Coefficient) heater, which are part of the aforementioned insulation resistance monitoring circuit, the first energy storage capacitor C... P Second energy storage capacitor C N It is in the nF range, and the filter capacitor C is... X It is on the order of tens of microseconds (µF), i.e., Cx >> C. N Therefore, the impedance of Cx is relative to C. N It can be ignored, and the bus resistance R P The resistance of N is typically in the tens to hundreds of kΩ range, and the first insulation resistance R P Second insulation resistance R N It is in the range of tens to thousands of MΩ, i.e., R N >>R P N, therefore R P The impedance of N compared to R N This can be ignored. Therefore, the first energy storage capacitor C can be obtained. P The equivalent circuit after charging is complete and control switch S1 is turned off is as follows: Figure 11 As shown.

[0096] Define variable Uy0 as the first energy storage capacitor C P The voltage across the capacitor at the moment charging is complete, uy(t) is the voltage across the first energy storage capacitor C. P The voltage across the capacitor is given at time t after charging is complete. The first energy storage capacitor C can be easily obtained. P The discharge formula is:

[0097]

[0098] Where RP / / N is the first insulation resistance R P Second insulation resistance R N The resistance after parallel connection, C at this time P and C N Let C and D represent the capacitance values ​​of the two energy storage capacitors, which are known values. Therefore, the capacitance C of the first energy storage capacitor after a preset time threshold t1 can be determined.P The discharge voltage Uy0 is given by the following formula:

[0099]

[0100] The value of RP / / N obtained by transforming formula (2) is:

[0101]

[0102] Under normal circumstances, the vehicle controller does not need to measure very precise insulation resistance, nor does it need to distinguish between positive and negative insulation resistance. Therefore, the first insulation resistance R can be determined based on formula (3). P Second insulation resistance R N The resistance value after parallel connection can meet the monitoring requirements (if either RP or RN is abnormally low, the total resistance RP / / N after parallel connection will also be low). Therefore, insulation resistance testing can be performed even without high voltage. An insulation resistance test can be performed before each high voltage connection to ensure the system's insulation resistance is normal, thus avoiding potential safety hazards caused by connecting high voltage when insulation is poor.

[0103] In one embodiment, reference is made to Figure 13 , Figure 13 This is a connection diagram of the fourth embodiment of the insulation resistance monitoring circuit of this application. The isolation sampling subunit 12 includes a first isolation sampling subunit and a second isolation sampling subunit.

[0104] The first isolated sampling subunit is connected to the high-voltage positive terminal of the high-voltage power supply unit 20 and the ground of the outer casing of the high-voltage power supply unit 20;

[0105] The second isolation sampling subunit is connected to the high-voltage negative terminal of the high-voltage power supply unit 20 and the outer casing ground of the high-voltage power supply unit 20.

[0106] In this embodiment, if it is necessary to calculate the accurate values ​​of RP and RN, an isolated sampling subunit can be added, such as... Figure 13 As shown. After the control switch S1 is closed, the first energy storage capacitor C needs to be activated first. P Second energy storage capacitor C N Once the voltage stabilizes after charging, the ratio of RP to (RPN+RN) can be derived through two isolated sampling channels. Then, by sampling after the specific discharge time, the parallel resistance of RP and RN can be calculated. Further reference... Figure 14 , Figure 14 This is a connection diagram of the fifth embodiment of the insulation resistance monitoring circuit of this application, which shows that synchronous charging is achieved through two control switches S1. In use... Figure 14 After charging, the equivalent diagram of discharging is as follows: Figure 15 As shown, Figure 15This is another equivalent connection diagram of the insulation resistance monitoring circuit of this application, that is, the first energy storage capacitor C can be established at this time. P Second energy storage capacitor C N The discharge equation, combined with the previous parallel resistance of RP and RN, yields two equations and two unknowns. This allows for the precise determination of the resistance values ​​of RP and RN, enabling insulation resistance monitoring based on these accurate values ​​without the need for a high-voltage power supply.

[0107] This application also provides an air conditioning compressor, which includes a controller, a motor and a compressor unit. The controller is connected to the motor and the motor is connected to the compressor unit. The controller is equipped with an insulation resistance monitoring circuit as described above.

[0108] It is worth noting that, according to the air conditioner compressor of this utility model embodiment, the controller in the air conditioner compressor executes the following program: when the energy storage capacitor is charged to the first state, the isolation voltage source is controlled to stop charging, and at a preset time threshold after the charging stops, the isolation sampling subunit acquires the second capacitor voltage of the energy storage capacitor, so as to monitor the insulation resistance in the high-voltage power supply unit based on the second capacitor voltage, the first capacitor voltage and the preset time threshold. In this way, the insulation resistance in the high-voltage power supply unit can be monitored by the second capacitor voltage, the first capacitor voltage and the preset time threshold, which can realize the insulation resistance monitoring without relying on the high-voltage power supply and the high-voltage power supply unit being connected to power.

[0109] The controller incorporates an insulation resistance monitoring circuit connected to the motor. This allows for insulation resistance monitoring even when the motor is operating at high voltage, without relying on a high-voltage power supply unit. The motor then drives the compressor to function as an air conditioning compressor. It's worth noting that the air conditioning compressor can also include other hardware, such as a housing and circuit board, to separately house the high-voltage power supply unit and insulation detection unit within the insulation resistance monitoring circuit on the circuit board. The circuit board, its circuitry, and the motor are then encapsulated within the housing to form the air conditioning compressor. The controller controls the insulation resistance monitoring circuit to monitor insulation resistance without relying on a high-voltage power supply unit. It also drives the inverter drive unit to control the motor connected to the inverter drive unit. Furthermore, the insulation resistance monitoring circuit can also be integrated into other high-voltage operating circuits, such as a PTC heater.

[0110] The device provided in this application solves the technical problem of achieving insulation resistance monitoring without relying on a high-voltage power supply and a high-voltage power supply unit for power connection. Compared with the prior art, the beneficial effects of the device provided in this application are the same as those of the insulation resistance monitoring circuit provided in the above embodiments, and will not be repeated here.

[0111] This application also provides a vehicle that includes the aforementioned air conditioning compressor.

[0112] It is worth noting that the air conditioning compressor can be installed on the vehicle to achieve insulation resistance monitoring without relying on a high-voltage power supply or connection to a high-voltage power supply unit. It is also worth noting that other hardware can be installed on the vehicle, which will not be detailed here. The entire air conditioning compressor can be installed on the vehicle or on other products; this is not a limitation.

[0113] The device provided in this application solves the technical problem of achieving insulation resistance monitoring without relying on a high-voltage power supply and a high-voltage power supply unit for power connection. Compared with the prior art, the beneficial effects of the vehicle provided in this application are the same as those of the insulation resistance monitoring circuit provided in the above embodiments, and will not be repeated here.

[0114] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. An insulation resistance monitoring circuit, characterized in that, The insulation resistance monitoring circuit includes a high-voltage power supply unit and an insulation detection unit. The insulation detection unit is connected to the high-voltage power supply unit and includes: An isolated voltage source, the input terminal of which is connected to an external low-voltage power supply, and the output terminal of which is connected to the high-voltage power supply unit; An isolation sampling subunit, the input terminal of which is connected to the high-voltage power supply unit; A control chip is connected to the output terminal of the isolation sampling subunit and the control terminal of the isolation voltage source. The voltage value of the energy storage capacitor in the high-voltage power supply unit after charging stops is collected by the isolation sampling subunit and transmitted to the control chip. The control chip monitors the insulation resistance in the high-voltage power supply unit based on the voltage value and the corresponding acquisition time.

2. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The insulation resistance monitoring circuit also includes: A control switch is connected to the output terminal of the isolation voltage source and the high-voltage power supply unit. The control switch is used to control the isolation voltage source to charge or stop charging the energy storage capacitor in the high-voltage power supply unit.

3. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The isolation voltage source includes: An isolation voltage controller, wherein the control terminal of the isolation voltage controller is connected to the control chip, and the input terminal of the isolation voltage controller is connected to the low-voltage power supply; An isolation transformer, wherein the primary winding of the isolation transformer is connected to the output terminal of the isolation voltage controller, the primary winding is wound on the transformer core of the isolation transformer, and the first end of the secondary winding of the isolation transformer is connected to the high-voltage power supply unit; A diode, wherein the anode of the diode is connected to the second end of the secondary coil, and the cathode of the diode is connected to the high-voltage power supply unit.

4. The insulation resistance monitoring circuit as described in claim 3, 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 first end of the secondary coil is connected to the high-voltage positive terminal, and the cathode of the diode is connected to the ground of the housing, or... The first end of the secondary coil is connected to the high-voltage negative terminal, and the cathode of the diode is connected to the ground of the housing, or... The first end of the secondary coil is connected to the outer casing ground, and the cathode of the diode is connected to the high-voltage positive terminal, or... The first end of the secondary coil is connected to the outer casing ground, and the cathode of the diode is connected to the high-voltage negative terminal.

5. The insulation resistance monitoring circuit as described in claim 3, characterized in that, The isolated sampling subunit includes an isolated sampling operational amplifier, which includes a positive sampling terminal and a negative sampling terminal. The positive sampling terminal is connected to the first end of the secondary coil, and the negative sampling terminal is connected to the cathode of the diode, or... The negative sampling terminal is connected to the first end of the secondary coil, and the positive sampling terminal is connected to the cathode of the diode.

6. The insulation resistance monitoring circuit as described in claim 1, characterized in that, The high-voltage power supply unit includes: A first energy storage capacitor, the first end of which is connected to the high voltage positive terminal of the high voltage power supply unit, and the second end of which is connected to the ground of the outer casing of the high voltage power supply unit. The second energy storage capacitor has its second terminal connected to the high-voltage negative terminal of the high-voltage power supply unit, and its first terminal connected to the ground of the outer casing. A first insulation resistor, the first end of which is connected to the high voltage positive electrode, and the second end of which is connected to the ground of the outer casing; The second insulation resistor has its second end connected to the high voltage negative electrode and its first end connected to the outer casing ground.

7. The insulation resistance monitoring circuit as described in claim 6, characterized in that, The high-voltage power supply unit also includes: A filter capacitor, wherein the first end of the filter capacitor is connected to the high voltage positive terminal of the high voltage power supply unit, and the second end of the filter capacitor is connected to the high voltage negative terminal of the high voltage power supply unit; The bus resistor has its first end connected to the high-voltage positive terminal of the high-voltage power supply unit, and its second end connected to the high-voltage negative terminal of the high-voltage power supply unit.

8. The insulation resistance monitoring circuit according to any one of claims 1 to 7, characterized in that, The isolation sampling subunit includes a first isolation sampling subunit and a second isolation sampling subunit; The first isolated sampling subunit is connected to the high-voltage positive terminal of the high-voltage power supply unit and the ground of the high-voltage power supply unit's casing; The second isolation sampling subunit is connected to the high-voltage negative terminal of the high-voltage power supply unit and the ground of the high-voltage power supply unit.

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

10. A vehicle, characterized in that, The vehicle includes the air conditioning compressor as described in claim 9.

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