A Y-capacitor analog test circuit, method, system, and apparatus

Abstract

This application provides a Y-capacitor simulation test circuit, method, system, and apparatus, relating to the field of circuit technology. The Y-capacitor simulation test circuit includes: an interlock contactor, a capacitor switching unit, a capacitance detection unit, and a controller. The capacitor switching unit includes multiple switching switches connected in parallel and multiple Y capacitors connected in series with each switching switch. The interlock contactor is connected to the capacitor switching unit, which is also connected to the capacitance detection unit. The capacitance detection unit is further connected to the controller, which is also connected to the multiple switching switches and the interlock contactor of the capacitor switching unit. The controller is also used to receive capacitor switching commands. This application can improve the accuracy of the Y-capacitor value required for fault simulation.

Description

Technical Field

[0001] This invention relates to the field of circuit technology, and more specifically, to a Y capacitor analog test circuit, method, system, and apparatus. Background Technology

[0002] In recent years, with the rapid expansion of the electric vehicle market, the resulting safety issues have become increasingly prominent.

[0003] Y-capacitors, as a common component in electric vehicles, are used not only between the positive and negative terminals and ground wire of the charging pile output, but also between the positive and negative terminals of the power battery and the metal casing of the battery pack, or between the entire vehicle body.

[0004] To ensure charging safety and the insulation detection function of electric vehicles, the capacitance value of the Y capacitor must not exceed the requirements of international standards. In order to simulate the faults caused by the Y capacitor during the charging process, different Y capacitor values ​​need to be switched. The accuracy of the switched Y capacitor values ​​plays a crucial role in fault simulation. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a Y-capacitor simulation test circuit, method, system, and apparatus to improve the accuracy of the Y-capacitor value required for fault simulation.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:

[0007] In a first aspect, embodiments of this application provide a Y capacitor simulation test circuit, which includes: an interlock contactor, a capacitor switching unit, a capacitance detection unit, and a controller. The capacitor switching unit includes multiple switching switches connected in parallel and multiple Y capacitors connected in series with the switching switches.

[0008] The interlock contactor is connected to the capacitor switching unit, the capacitor switching unit is also connected to the capacitance detection unit, the capacitance detection unit is also connected to the controller, the controller is also connected to the plurality of switching switches of the capacitor switching unit and the interlock contactor, and the controller is also used to receive capacitor switching commands.

[0009] Optionally, the Y-capacitor simulation test circuit further includes: a soft-start unit;

[0010] The interlock contactor is connected to the capacitor switching unit through the soft-start unit, and the controller is also connected to the soft-start unit.

[0011] Optionally, the Y-capacitor simulation test circuit further includes: a discharge unit;

[0012] The discharge unit is connected in parallel with the capacitor switching unit, and the controller is also connected to the discharge unit.

[0013] Optionally, the Y-capacitor simulation test circuit further includes: a fuse;

[0014] The interlock contactor is connected to the capacitor switching unit via the fuse.

[0015] Optionally, the soft-start unit includes: a soft-start contactor and a soft-start resistor;

[0016] The interlock contactor is connected to the capacitor switching unit through the soft-start contactor, the soft-start resistor is connected in parallel across the two ends of the soft-start contactor, and the controller is also connected to the soft-start contactor.

[0017] Optionally, the discharge unit includes: a discharge contactor and a discharge resistor;

[0018] The discharge contactor and the discharge resistor are connected in series and then in parallel with the capacitor switching unit. The controller is also connected to the discharge contactor.

[0019] Optionally, the capacitance detection unit is a multivibrator, the input of which is connected to the capacitor switching unit, and the output of which is connected to the first input of the controller.

[0020] Secondly, embodiments of this application also provide a Y-capacitor simulation test method, applied to a controller in a Y-capacitor simulation test circuit as described in any of the first aspects, the method comprising:

[0021] Receive capacitor switching command, the capacitor switching command includes: initial switching capacitor value;

[0022] The capacitor switching unit is controlled to switch capacitors according to the initial switching capacitor value.

[0023] The actual switching capacitance value of the capacitor switching unit is sent by the capacitance detection unit;

[0024] The initial switching capacitor value is calibrated based on the actual switching capacitor value until the actual switching capacitor value meets the preset switching threshold.

[0025] Optionally, calibrating the initial switching capacitor value based on the actual switching capacitor value until the actual switching capacitor value of the capacitor switching unit meets the preset switching threshold includes:

[0026] If the actual switching capacitor value does not meet the preset switching threshold, the initial switching capacitor value is calibrated based on the initial switching capacitor value and the actual switching capacitor value to obtain the target switching capacitor value.

[0027] The capacitor switching unit is controlled to switch capacitors according to the target switching capacitor value until the actual switching capacitor value meets the preset switching threshold.

[0028] Optionally, if the Y-capacitor simulation test circuit includes a soft-start unit, and the method further includes controlling the capacitor switching unit to switch according to the target switching capacitor value until the actual switching capacitor value meets the preset switching threshold:

[0029] The interlock contactor is closed, and the soft-start contactor of the soft-start unit is opened, so that the charging power supply pre-charges the Y capacitor in the capacitor switching unit through the soft-start resistor of the soft-start unit.

[0030] After the Y capacitor is pre-charged, the soft-start contactor of the soft-start unit is closed.

[0031] Optionally, if the Y-capacitor simulation test circuit includes a discharge unit, the method further includes:

[0032] According to the received switching stop command, the interlock contactor is controlled to open, and the discharge contactor to the discharge unit is controlled to close, so as to discharge the Y capacitor in the capacitor switching unit through the discharge resistor of the discharge unit.

[0033] Thirdly, embodiments of this application also provide a Y-capacitor simulation test system, the Y-capacitor simulation test system comprising: a host computer and a Y-capacitor simulation test circuit as described in any of the first aspects, the host computer being connected to a controller in the Y-capacitor simulation test circuit, and being used to send capacitor switching instructions and switching stop instructions to the controller, the controller being used to execute the Y-capacitor simulation test method as described in any of the second aspects.

[0034] Fourthly, embodiments of this application also provide a Y-capacitor simulation test device, the Y-capacitor simulation test device comprising: a power conversion module and a Y-capacitor simulation test circuit as described in any of the first aspects;

[0035] The input terminal of the power conversion module is connected to the mains power supply. The positive and negative output terminals of the power conversion module are respectively connected to the capacitor switching unit of the Y capacitor simulation test circuit through power supply contactors to provide charging power to the capacitor switching unit.

[0036] The beneficial effects of this application are:

[0037] This application provides a Y-capacitor simulation test circuit, method, system, and apparatus. The controller and capacitance detection module detect and judge the capacitance value switched in the circuit. The controller controls the capacitor switching unit to continuously calibrate the capacitance value switched to the circuit until the actual switched capacitance value meets the switching requirements of fault simulation, thereby improving the accuracy and precision of the switched capacitance value and accurately simulating faults. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 Schematic diagram of the Y-capacitor analog test circuit provided in the embodiments of this application Figure 1 ;

[0040] Figure 2 Schematic diagram of the Y-capacitor analog test circuit provided in the embodiments of this application Figure 2 ;

[0041] Figure 3 The circuit schematic diagram of the Y-capacitor simulation test circuit provided in the embodiments of this application;

[0042] Figure 4 This is a schematic diagram of the working principle of the soft-start unit provided in the embodiments of this application;

[0043] Figure 5 This is a schematic diagram of the working principle of the discharge unit provided in the embodiments of this application;

[0044] Figure 6 The circuit schematic of the capacitance detection unit provided in the embodiments of this application;

[0045] Figure 7 A flowchart illustrating the Y-capacitance simulation test method provided in this application embodiment. Figure 1 ;

[0046] Figure 8 A flowchart illustrating the Y-capacitance simulation test method provided in this application embodiment. Figure 2 ;

[0047] Figure 9 This is a schematic block diagram of the Y-capacitor simulation test system provided in the embodiments of this application;

[0048] Figure 10 This is a schematic block diagram of the Y-capacitor simulation test device provided in an embodiment of this application. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0050] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0051] Furthermore, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0053] Please refer to Figure 1 The schematic diagram of the Y-capacitor analog test circuit provided in the embodiments of this application is shown below. Figure 1 ,like Figure 1 As shown, the Y capacitor simulation test circuit includes: an interlock contactor 11, a capacitor switching unit 12, a capacitance detection unit 13, and a controller 14. The capacitor switching unit 12 includes multiple switching switches connected in parallel and multiple Y capacitors connected in series with the switching switches.

[0054] Interlock contactor 11 is connected to capacitor switching unit 12, capacitor switching unit 12 is also connected to capacitance detection unit 13, capacitance detection unit 13 is also connected to controller 14, controller 14 is also connected to multiple switching switches of capacitor switching unit 12 and interlock contactor 11, controller 14 is also used to receive capacitor switching commands.

[0055] In this embodiment, in order to ensure the normal operation of the Y capacitor simulation test circuit, a charging power supply is required to power the Y capacitor simulation test circuit so that the capacitor switching unit 12 can be charged by the charging power supply. Specifically, the charging power supply is connected to the capacitor switching unit 12 through the interlock contactor 11 to provide charging current for the Y capacitor in the capacitor switching unit 12.

[0056] Y capacitors, as a type of safety capacitor, can generally be connected across the live wire L or neutral wire N and the ground wire PE. In this embodiment, the positive output terminal DC+ or the negative output terminal DC- of the charging power supply is connected to one end of multiple switching switches in the capacitor switching unit 12 through the interlock contactor 11, and the other end of the multiple switching switches is connected to the ground wire PE through a Y capacitor.

[0057] In some embodiments, multiple Y capacitors can be connected to the ground wire PE via another interlocking contactor 11.

[0058] The interlock contactor 11 is closed by the controller 14 after the capacitor value of the capacitor switching unit 12 is successfully switched, so as to charge the Y capacitor switched in the capacitor switching unit 12 through the charging power supply. The interlock contactor 11 is also opened by the controller 14 after the capacitor switching unit 12 is finished, so as to discharge the Y capacitor switched in the capacitor switching unit 12 and avoid the safety hazards caused by excessive energy on the Y capacitor.

[0059] The first input terminal of the controller 14 is used to connect to the host computer to receive the capacitor switching command sent by the host computer. The capacitor switching command is used to indicate the initial switching capacitor value to be switched. The controller 14 controls some of the switching switches in the capacitor switching unit 12 to close according to the capacitor switching command, so as to switch the Y capacitor connected to the closed switching switch into the loop.

[0060] The output of capacitor switching unit 12 is connected to the input of capacitance detection unit 13 so that the capacitance detection unit 13 can detect the actual switching capacitance value of capacitor switching unit 12. The output of capacitance detection unit 13 is connected to the second input of controller 14 so that the actual switching capacitance value can be sent to controller 14. Controller 14 can then determine whether the actual switching capacitance value meets the switching requirements based on the initial switching capacitance value and the actual switching capacitance value. If not, the initial switching capacitance value is calibrated based on the initial switching capacitance value and the actual switching capacitance value to obtain the target switching capacitance value. Controller 14 then re-controls the partial switching switches in capacitor switching unit 12 to close based on the target switching capacitance value. Controller 14 then determines whether the actual switching capacitance value detected by capacitance detection unit 13 meets the switching requirements again, and continuously calibrates until the switching requirements are met.

[0061] The Y-capacitor simulation test circuit provided in the above embodiment detects and judges the capacitor value switched in the loop through the controller and the capacitance detection module. The controller controls the capacitor switching unit to continuously calibrate the capacitor value switched to the loop until the actual switched capacitor value meets the switching requirements of fault simulation, thereby improving the accuracy and precision of the switched capacitor value and accurately simulating faults.

[0062] To ensure the safety of the Y-capacitor analog test circuit, embodiments of this application also provide various protection units. The following, in conjunction with... Figure 2 The implementation methods of various protection units provided in the embodiments of this application will be described.

[0063] Please refer to Figure 2 The schematic diagram of the Y-capacitor analog test circuit provided in the embodiments of this application is shown below. Figure 2 ,like Figure 2 As shown, the Y capacitor simulation test circuit also includes: a soft start unit 15, an interlock contactor 11 connected to a capacitor switching unit 12 via the soft start unit 15, and a controller also connected to the soft start unit 15.

[0064] In this embodiment, the soft-start unit 15 is connected between the interlock contactor 11 and the capacitor switching unit 12. When the controller 14 controls the interlock contactor 11 to close and the charging power supply charges the Y capacitor switched in the capacitor switching unit 12, the soft-start unit 15 first pre-charges the switched Y capacitor so that the voltage across the switched Y capacitor is equal to the voltage between the positive output terminal DC+ or the negative output terminal DC- of the charging power supply and the ground line PE. The soft-start unit 15 can limit the charging circuit at the moment the Y capacitor is switched to the circuit, and avoid the charging current at the moment the Y capacitor is switched to the circuit being too large, which may damage the Y capacitor.

[0065] Specifically, after the controller 14 determines that the actual switching capacitor value of the capacitor switching unit 12 meets the switching requirements, it controls the soft start unit 15 to enter the soft start charging mode and controls the interlock contactor 11 to close, so that the charging power supply pre-charges the Y capacitor switched in the circuit through the soft start unit. When the pre-charging is completed, the controller 14 controls the soft start unit 15 to exit the soft start charging mode, and the charging power supply directly charges the Y capacitor switched in the circuit.

[0066] The Y capacitor simulation test circuit provided in the above embodiment controls the charging power supply to pre-charge the Y capacitor switched in the circuit through the soft start unit, which limits the charging circuit at the moment the Y capacitor is switched in the circuit, avoids the excessive charging current at the moment the Y capacitor is switched in the circuit from damaging the Y capacitor, and improves the safety of the Y capacitor simulation test circuit.

[0067] In one possible implementation, such as Figure 2As shown, the Y capacitor simulation test circuit also includes: a discharge unit 16, which is connected in parallel with the capacitor switching unit 12, and the controller 14 is also connected to the discharge unit 16.

[0068] In this embodiment, the discharge unit 16 is connected in parallel across the two ends of the capacitor switching unit 12 so that after the capacitor switching unit 12 stops switching, the discharge unit 16 discharges the Y capacitor, thus avoiding the risk of electric shock caused by the Y capacitor being charged.

[0069] Specifically, under normal conditions, the discharge unit 16 is in the off state. The controller 14 is also used to receive the switching stop command sent by the host computer. When the controller 14 determines that it is necessary to stop switching the Y capacitor in the loop according to the switching stop command, the controller 14 controls the discharge unit 16 to be turned on so that the Y capacitor can be discharged through the discharge unit 16.

[0070] The Y capacitor simulation test circuit provided in the above embodiment discharges the Y capacitor in the capacitor switching unit by connecting a discharge unit in parallel across the capacitor switching unit after the switching is completed, thereby avoiding the risk of electric shock caused by the Y capacitor being charged and improving the safety of the Y capacitor simulation test circuit.

[0071] In one possible implementation, such as Figure 2 As shown, the Y capacitor simulation test circuit also includes: a fuse 17; and an interlock contactor 11 connected to the capacitor switching unit 12 via the fuse 17.

[0072] In this embodiment, a fuse 17 is provided between the charging power supply and the capacitor switching unit 12 to provide short-circuit protection for the Y capacitor analog test circuit when a short-circuit fault occurs in the Y capacitor analog test circuit.

[0073] In some embodiments, when the Y capacitor analog test circuit includes a soft-start unit, the fuse 17 is connected between the interlock contactor 11 and the soft-start unit 15.

[0074] The Y-capacitor simulation test circuit provided in the above embodiment provides short-circuit protection for the Y-capacitor simulation test circuit when a short-circuit fault occurs, by setting a fuse between the charging power supply and the capacitor switching unit. This prevents overcurrent caused by the short-circuit fault from damaging the Y-capacitor simulation test circuit and improves the safety of the Y-capacitor simulation test circuit.

[0075] The following combination Figure 3 The specific implementation of the Y-capacitor analog test circuit provided in the embodiments of this application will be described.

[0076] Please refer to Figure 3 The diagram shows the circuit schematic of the Y-capacitor simulation test circuit provided in the embodiments of this application. Figure 3 As shown, the interlocking contactor 11 between the positive output terminal DC+ or the negative output terminal DC- of the charging power supply and the capacitor switching unit 12 is contactor K11, the interlocking contactor 11 between the ground wire PE and the capacitor switching unit 12 is contactor K12, and the fuse 17 between contactor K11 and the capacitor switching unit 12 is fuse F1.

[0077] For example, since the maximum instantaneous operating current of the Y capacitor analog test circuit is approximately within 1A, the fuse F1 is selected as 1A.

[0078] like Figure 3 As shown, the capacitor switching unit 12 includes multiple switching switches K1-K10 connected in parallel, and multiple Y capacitors Y1-Y10 connected in series with the switching switches K1-K10 respectively. The Y capacitors Y1-Y10 can achieve capacitor switching values ​​in the range of 0.01uF-10uF, with a step of 0.01uF and an accuracy of 5%.

[0079] After receiving the initial switching capacitor value sent by the host computer, or after determining the target switching capacitor value according to the capacitance detection unit, the controller 14 controls some of the switching switches K1-K10 to close, so that the sum of the capacitance values ​​of the Y capacitors connected to the closed switching switches is equal to the initial switching capacitor value or the target switching capacitor value.

[0080] It should be noted that the number of Y capacitors and the capacitance value of each Y capacitor can be selected according to actual needs. The example given in this embodiment is just one example.

[0081] For example, please refer to Figure 4 The diagram below illustrates the working principle of the soft-start unit provided in this embodiment of the application. Figure 3 and Figure 4 As shown, the soft start unit 15 includes: a soft start contactor K13 and a soft start resistor R1; the contactor K11 is connected to the capacitor switching unit 12 through the soft start contactor K13, the soft start resistor R1 is connected in parallel across the two ends of the soft start contactor K13, and the controller 14 is also connected to the soft start contactor K13.

[0082] In this embodiment, before the Y capacitor switched in the capacitor switching unit 12 is connected between the positive output terminal DC+ or the negative output terminal DC- of the charging power supply and the ground line PE, the controller 14 controls the contactor K11 to close and controls the soft-start contactor K13 to open, connecting the soft-start resistor R1 in series with the switched Y capacitor. The soft-start unit 15 enters the soft-start charging mode, and the charging power supply pre-charges the switched Y capacitor through the soft-start resistor R1. After the Y capacitor is pre-charged, the controller 14 controls the soft-start contactor K13 to close, short-circuiting the soft-start resistor R1. The soft-start unit 15 exits the soft-start charging mode, and the Y capacitor switched in the capacitor switching unit 12 is directly connected between the positive output terminal DC+ or the negative output terminal DC- of the charging power supply and the ground line PE.

[0083] The process of pre-charging the Y capacitor through the soft-start unit 15 takes about 10ms, and the instantaneous maximum current of pre-charging is less than 1A, ensuring the safety of the Y capacitor.

[0084] For example, please refer to Figure 5 The diagram below shows the working principle of the discharge unit provided in the embodiments of this application. Figure 3 and Figure 5 As shown, the discharge unit 16 includes a discharge contactor K14 and a discharge resistor R2; the discharge contactor K14 and the discharge resistor R2 are connected in series and then connected in parallel with the capacitor switching unit 12, and the controller 14 is also connected to the discharge contactor K14.

[0085] In this embodiment, after receiving the switching stop command, the controller 14 needs to discharge the Y capacitor to ensure the safety of the Y capacitor simulation test circuit and avoid safety hazards caused by accidental contact due to the charge on the Y capacitor.

[0086] Specifically, contactors K11 and K12 are interlocked with discharge contactor K14. When charging the Y capacitor, controller 14 controls contactors K11 and K12 to close and controls discharge contactor K14 to open. When discharging the Y capacitor, controller 14 controls contactors K11 and K12 to open and controls discharge contactor K14 to close. After discharge contactor K14 is closed, the charge on the Y capacitor is discharged through discharge resistor R2. After the discharge is completed, discharge contactor K14 is controlled to open.

[0087] The discharge time of the Y capacitor through the discharge unit is approximately 10ms.

[0088] Please refer to Figure 6 Here is a circuit schematic diagram of the capacitance detection unit provided in an embodiment of this application, as shown below. Figure 6As shown, the capacitance detection unit 13 is a multivibrator composed of a 555 timer, a first timing resistor R11, a second timing resistor R12, and a timing capacitor C.

[0089] The multivibrator has 8 ports. The low-level trigger terminal (port 2) of the multivibrator is connected to the high-level trigger terminal (port 6) as the input terminal of the multivibrator and connected to the output terminal of the capacitor switching unit 12. The output terminal (port 3) of the multivibrator is connected to the controller 14.

[0090] The multivibrator detects the output voltage of the capacitor switching unit 12 and outputs the oscillation frequency based on the first timing resistor R11, the second timing resistor R12 and the timing capacitor C. The controller 14 can calculate the actual switching capacitance value of the capacitor switching unit 12 based on the oscillation frequency. The capacitance value detection accuracy of the multivibrator is 5%.

[0091] Based on the Y-capacitor simulation test circuit provided in the above embodiments, this application also provides a Y-capacitor simulation test method for a controller applied in the above-mentioned Y-capacitor simulation test circuit.

[0092] Please refer to Figure 7 The following is a flowchart illustrating the Y-capacitance simulation test method provided in the embodiments of this application. Figure 1 ,like Figure 7 As shown, the method may include:

[0093] S10: Receive capacitor switching command, which includes the initial switching capacitor value.

[0094] S20: Control the capacitor switching unit to switch according to the initial switching capacitor value.

[0095] S30: Receive the actual switching capacitance value of the capacitor switching unit sent by the capacitance detection unit.

[0096] S40: The initial switching capacitor value is calibrated according to the actual switching capacitor value until the actual switching capacitor value meets the preset switching threshold.

[0097] In this embodiment, the controller is connected to the host computer to receive the capacitor switching command sent by the host computer. The capacitor switching command is used to indicate the initial switching capacitor value to be switched. The controller controls some switching switches in the capacitor switching unit to close according to the capacitor switching command, so as to switch the Y capacitor connected to the closed switching switch into the loop.

[0098] The capacitance detection unit is connected to the capacitor switching unit to detect the actual switched capacitance value of the capacitor switching unit and send the actual switched capacitance value to the controller. The controller determines whether the actual switched capacitance value meets the preset switching threshold. If it does not meet the threshold, the initial switched capacitance value is calibrated, and the capacitor switching unit is re-switched according to the calibrated initial switched capacitance value. The controller then determines whether the new actual switched capacitance value meets the preset switching threshold again. This process is repeated until the actual switched capacitance value meets the preset switching threshold.

[0099] In one possible implementation, please refer to Figure 8 The following is a flowchart illustrating the Y-capacitance simulation test method provided in the embodiments of this application. Figure 2 ,like Figure 8 As shown, the process of S40 above, which calibrates the initial switching capacitor value based on the actual switching capacitor value until the actual switching capacitor value meets the preset switching threshold, may include:

[0100] S41: If the actual switching capacitor value does not meet the preset switching threshold, the initial switching capacitor value is calibrated based on the initial switching capacitor value and the actual switching capacitor value to obtain the target switching capacitor value.

[0101] S42: Control the capacitor switching unit to switch according to the target switching capacitor value until the actual switching capacitor value meets the preset switching threshold.

[0102] In this embodiment, the controller determines whether the actual switching capacitor value meets the preset switching threshold based on the initial switching capacitor value and the actual switching capacitor value. If it does not meet the threshold, the controller calibrates the initial switching capacitor value based on the initial switching capacitor value and the actual switching capacitor value to obtain the target switching capacitor value. The controller then controls the partial switching switches in the capacitor switching unit to close again based on the target switching capacitor value, and determines whether the preset switching threshold is met based on the actual switching capacitor value detected again by the capacitance detection unit. The controller then continuously calibrates until the preset switching threshold is met.

[0103] In some embodiments, the preset switching threshold is an error threshold between the initial switching capacitor value and the actual switching capacitor value. Based on the error between the initial and actual switching capacitor values, the switching capacitor value is calibrated multiple times until the error meets the preset switching threshold. If the error after multiple calibrations still does not meet the preset switching threshold, calibration is stopped, and an alarm signal is sent to the host computer to indicate that the capacitor error is unqualified.

[0104] For example, the calibration process is explained by taking a preset switching threshold where the error between the initial switching capacitor value and the actual switching capacitor value is ±10%.

[0105] Specifically, based on the initial switching capacitor value C 初 and the actual switching capacitor value C实 Calculate the cutting error value ΔC, the cutting error η = ΔC / C 初 *100%, if the switching error η>±10%, it is determined that the switching value does not meet the preset switching threshold. The initial switching capacitor value is compensated, and the compensated target switching capacitor value C=C 初 +ΔC, the controller directs the capacitor switching unit to switch to the target switching capacitance value, and the capacitance detection unit re-detects the actual switching capacitance value C. 实 And based on the initial switching capacitor value C 初 And the new actual switching capacitor value C 实 Recalculate the switching error value ΔC. If the switching error η≦±10%, the switching capacitor value is deemed qualified. Otherwise, perform calibration again. If calibration is performed within the specified number of times until the switching error η≦±10%, the calibration is deemed successful. If the number of calibrations exceeds the specified number of times, but the switching error η>±10%, the calibration is deemed unqualified and the switching capacitor value is deemed unqualified.

[0106] The Y-capacitor simulation test method provided in the above embodiment detects and judges the initial switching capacitor value and the actual switching capacitor value through the controller and the capacitance detection module. When the actual switching capacitor value does not meet the switching requirements, the controller controls the capacitor switching unit to continuously calibrate the capacitor value switched to the circuit until the actual switching capacitor value meets the switching requirements of the fault simulation, thereby improving the accuracy and precision of the switching capacitor value and accurately simulating the fault.

[0107] In one possible implementation, if the Y-capacitor simulation test circuit includes a soft-start unit, after the capacitor switching unit is controlled to switch according to the target switching capacitor value until the actual switching capacitor value meets the preset switching value, the method may further include:

[0108] The control interlock contactor is closed, and the control soft start contactor of the soft start unit is opened, so that the charging power supply pre-charges the Y capacitor in the capacitor switching unit through the soft start resistor of the soft start unit; after the Y capacitor is pre-charged, the control soft start contactor of the soft start unit is closed.

[0109] In this embodiment, after the controller determines that the actual switching capacitor value of the capacitor switching unit meets the switching requirements, it controls the soft-start contactor to open, so that the soft-start resistor is connected in series with the switched Y capacitor. The soft-start unit enters the soft-start charging mode and controls the interlock contactor to close, so that the charging power supply pre-charges the switched Y capacitor in the circuit through the soft-start resistor. After the pre-charging is completed, the controller controls the soft-start contactor to close, short-circuiting the soft-start resistor. The soft-start unit exits the soft-start charging mode, and the switched Y capacitor in the capacitor switching unit is directly connected between the positive output terminal DC+ or the negative output terminal DC- of the charging power supply and the ground line PE. The charging power supply directly charges the switched Y capacitor in the circuit.

[0110] The Y capacitor simulation test method provided in the above embodiment controls the charging power supply to pre-charge the Y capacitor switched in the circuit through the slow-start resistor in the slow-start unit, limiting the charging circuit at the moment the Y capacitor is switched in the circuit, avoiding damage to the Y capacitor caused by excessive charging current at the moment the Y capacitor is switched in the circuit, and improving the safety of the Y capacitor simulation test circuit.

[0111] In one possible implementation, if the Y-capacitor simulation test circuit includes a discharge unit, the method may further include:

[0112] According to the received switching stop command, the interlock contactor is controlled to open, and the discharge contactor to the discharge unit is controlled to close, so as to discharge the Y capacitor in the capacitor switching unit through the discharge resistor of the discharge unit.

[0113] In this embodiment, after receiving the switching stop command, the controller needs to discharge the Y capacitor. The controller controls the interlock contactor to open to disconnect the charging voltage provided by the charging power supply, and controls the discharge contactor to close. After the discharge contactor is closed, the charge on the Y capacitor is discharged through the discharge resistor R2. After the discharge is completed, the controller controls the discharge contactor to open.

[0114] The Y capacitor simulation test method provided in the above embodiments discharges the Y capacitor in the capacitor switching unit through the discharge resistor of the discharge unit after the switching is completed, thereby avoiding the risk of electric shock caused by the Y capacitor being charged and improving the safety of the Y capacitor simulation test circuit.

[0115] Based on the above embodiments, this application also provides a Y capacitance simulation test system. Please refer to... Figure 9 The diagram below shows the principle block diagram of the Y-capacitor simulation test system provided in the embodiments of this application. Figure 9 As shown, the Y capacitor simulation test system includes: a host computer 10 and a Y capacitor simulation test circuit 20. The host computer 100 is connected to the controller 14 in the Y capacitor simulation test circuit 20 and is used to send capacitor switching commands and switching stop commands to the controller 14.

[0116] In this embodiment, the host computer 10 sends a capacitor switching command to the controller 14, causing the controller 14 to control the capacitor switching unit 12 to switch the capacitor and execute the steps S10-S50 described above, calibrating the switched capacitor value and controlling the soft start unit 15 to perform a soft start. The host computer 10 sends a switching stop command to the controller 14, causing the controller 14 to control the discharge unit 16 to discharge the Y capacitor.

[0117] Based on the above embodiments, this application also provides a Y capacitance simulation testing device. Please refer to... Figure 10 This is a schematic block diagram of the Y-capacitance simulation test device provided in the embodiments of this application, as shown below. Figure 10 As shown, the Y-capacitor simulation test device includes: a power conversion module 30 and a Y-capacitor simulation test circuit 20.

[0118] The three wires L1, L2 and L3 of the power conversion module 30 are connected to the mains power supply through contactors K0-1, K02- and K0-3 respectively. The positive output terminal DC+ and the negative output terminal DC- of the power conversion module 30 are connected to the capacitor switching unit of the Y capacitor simulation test circuit 20 through power supply contactors to provide charging power to the capacitor switching unit.

[0119] In this embodiment, the Y capacitor simulation test device is installed in the charging pile. The power conversion module 30 is used to convert the AC power from the grid power supply into DC power. The positive output terminal DC+ and the negative output terminal DC- of the power conversion module 30 are connected to the charging interface of the electric vehicle to charge the electric vehicle.

[0120] The Y-capacitor simulation test circuit 20 is connected between the positive output terminal DC+ or the negative output terminal DC- of the power conversion module 30 and the ground wire PE. If the power supply contactor of the positive output terminal DC+ of the power conversion module 30 is closed, the capacitor switching unit is provided with charging power through the positive output terminal DC+ of the power conversion module 30; if the power supply contactor of the negative output terminal DC- of the power conversion module 30 is closed, the capacitor switching unit is provided with charging power through the negative output terminal DC- of the power conversion module 30.

[0121] It should be noted that the Y capacitor simulation test circuit is used to simulate Y capacitor faults during the charging process. When the charging pile or electric vehicle detects a simulated Y capacitor fault, it controls the charging switches K10 and K20 to disconnect, thereby stopping the charging of the electric vehicle.

[0122] In some embodiments, such as Figure 10 As shown, the Y-capacitor simulation test device also includes an insulation resistance simulation test circuit 40. The positive output terminal DC+ and the negative output terminal DC- of the power conversion module 30 are respectively connected to the insulation resistance simulation test circuit through a power supply contactor, and are used to simulate and test the insulation resistance of electric vehicles.

[0123] In some embodiments, such as Figure 10 As shown, the Y-capacitor simulation test device also includes: an unbalanced bridge circuit 50 and an AC injection circuit 60. The unbalanced bridge circuit 50 provides the unbalanced bridge method, and the AC injection circuit 60 provides the AC injection method. The unbalanced bridge method and the AC injection method are two methods for insulation testing of electric vehicles.

[0124] In some embodiments, such as Figure 10As shown, a unidirectional conducting device is connected between the positive output terminal DC+ of the power conversion module and the charging interface of the electric vehicle. A switch KD1 is connected in parallel with the unidirectional conducting device. When the electric vehicle is being charged through the charging pile, the unidirectional conducting device is turned on. When the electric vehicle needs to discharge, the switch KD1 is turned on to discharge in reverse. For example, the unidirectional conducting device can be a diode D1.

[0125] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A Y-capacitor analog test circuit, characterized by, The Y-capacitor analog test circuit comprises an interlocking contactor, a capacitor switching unit, a capacitance detection unit and a controller, wherein The capacitor switching unit comprises a plurality of switching switches arranged in parallel and a plurality of Y-capacitors connected in series with the switching switches respectively; The interlocking contactor is connected to the capacitor switching unit, the capacitor switching unit is further connected to the capacitance detection unit, the capacitance detection unit is further connected to the controller, the controller is further connected to the plurality of switching switches of the capacitor switching unit and the interlocking contactor, the controller is further configured to receive a capacitor switching instruction, the capacitor switching instruction is used to indicate an initial switching capacitance value to be switched, and the controller controls the switching of part of the switching switches in the capacitor switching unit according to the capacitor switching instruction; The capacitance detection unit detects an actual switching capacitance value of the capacitor switching unit and sends the actual switching capacitance value to the controller, the controller calibrates the initial switching capacitance value according to the initial switching capacitance value and the actual switching capacitance value to obtain a target switching capacitance value, and controls the switching of part of the switching switches in the capacitor switching unit according to the target switching capacitance value, and the controller judges whether the switching requirement is met according to the actual switching capacitance value detected by the capacitance detection unit again until the actual switching capacitance value meets a preset switching threshold; The capacitance detection unit is a multivibrator composed of a 555 timer, a first timing resistor, a second timing resistor and a timing capacitor, an input end of the multivibrator is connected to the capacitor switching unit, and an output end of the multivibrator is connected to a first input end of the controller; the multivibrator detects an output voltage of the capacitor switching unit and outputs an oscillation frequency according to the first timing resistor, the second timing resistor and the timing capacitor, and the controller calculates the actual switching capacitance value of the capacitor switching unit according to the oscillation frequency.

2. The Y-capacitor analog test circuit of claim 1, wherein, The Y-capacitor analog test circuit further comprises a slow-start unit; The interlocking contactor is connected to the capacitor switching unit through the slow-start unit, and the controller is further connected to the slow-start unit.

3. The Y-capacitor analog test circuit of claim 1, wherein, The Y-capacitor analog test circuit further comprises a bleeder unit; The bleeder unit is connected to the capacitor switching unit in parallel, and the controller is further connected to the bleeder unit.

4. The Y-capacitor analog test circuit of claim 1, wherein, The Y-capacitor analog test circuit further comprises a safety tube; The interlocking contactor is connected to the capacitor switching unit through the safety tube.

5. The Y-capacitor analog test circuit of claim 2, wherein, The slow-start unit comprises a slow-start contactor and a slow-start resistor; The interlocking contactor is connected to the capacitor switching unit through the slow-start contactor, the slow-start resistor is connected across the slow-start contactor in parallel, and the controller is further connected to the slow-start contactor.

6. The Y-capacitor analog test circuit of claim 3, wherein, The bleeder unit comprises a bleeder contactor and a bleeder resistor; The bleeder contactor and the bleeder resistor are connected in series and connected to the capacitor switching unit in parallel, and the controller is further connected to the bleeder contactor.

7. A Y-capacitor analog test method, characterized by, The controller applied to the Y-capacitor analog test circuit in any one of claims 1-6, the method comprises: Receiving a capacitance switching instruction, the capacitance switching instruction comprising: an initial switching capacitance value; Controlling the capacitance switching unit to switch according to the initial switching capacitance value; Receiving an actual switching capacitance value of the capacitance switching unit sent by a capacitance value detection unit; Calibrating the initial switching capacitance value according to the actual switching capacitance value until the actual switching capacitance value meets a preset switching threshold; The capacitance value detection unit is a multivibrator composed of a 555 timer, a first timing resistor, a second timing resistor, and a timing capacitor, and the actual switching capacitance value of the capacitance switching unit sent by the capacitance value detection unit comprises: Receiving an oscillation frequency output by the multivibrator, the multivibrator outputs the oscillation frequency by detecting an output voltage of the capacitance switching unit and according to the first timing resistor, the second timing resistor, and the timing capacitor; Calculating the actual switching capacitance value according to the oscillation frequency; The calibration of the initial switching capacitance value according to the actual switching capacitance value until the actual switching capacitance value of the capacitance switching unit meets the preset switching threshold comprises: If the actual switching capacitance value does not meet the preset switching threshold, calibrating the initial switching capacitance value according to the initial switching capacitance value and the actual switching capacitance value to obtain a target switching capacitance value; Controlling the capacitance switching unit to switch according to the target switching capacitance value until the actual switching capacitance value meets the preset switching threshold.

8. The method of claim 7, wherein, If the Y capacitor analog test circuit comprises a slow start unit, after the capacitance switching unit is controlled to switch according to the target switching capacitance value until the actual switching capacitance value meets the preset switching threshold, the method further comprises: Controlling the interlock contactor to close and controlling a slow start contactor of the slow start unit to open, so that the charging power source pre-charges the Y capacitor in the capacitance switching unit through a slow start resistor of the slow start unit; After the Y capacitor pre-charging is completed, controlling the slow start contactor of the slow start unit to close.

9. The method of claim 7, wherein, If the Y capacitor analog test circuit comprises a bleeder unit, the method further comprises: According to the received switching stop instruction, controlling the interlock contactor to open and controlling a bleeder contactor of the bleeder unit to close, so as to discharge the Y capacitor in the capacitance switching unit through a bleeder resistor of the bleeder unit.

10. A Y-capacitor analog test system, characterized by, The Y capacitor analog test system comprises an upper computer and the Y capacitor analog test circuit according to any one of claims 1-6, the upper computer is connected to a controller in the Y capacitor analog test circuit, and is used to send a capacitance switching instruction and a switching stop instruction to the controller, and the controller is used to execute the Y capacitor analog test method according to any one of claims 7-9.

11. A Y-capacitor analog test apparatus, characterized by, The Y capacitor analog test device comprises a power conversion module and the Y capacitor analog test circuit according to any one of claims 1-6. The input end of the power conversion module is connected with a power grid power supply, and the positive output end and the negative output end of the power conversion module are respectively connected with a capacitor switching unit of the Y capacitor analog test circuit through power supply contactors, so as to provide a charging power supply for the capacitor switching unit.

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