A method and system for testing insulation resistance of vehicle-mounted film capacitors

Abstract

The present invention proposes a test method and system for the insulation resistance of vehicle-mounted film capacitors. The test method for the insulation resistance of vehicle-mounted film capacitors includes: charging the capacitor and recording the voltage data of the capacitor after charging is completed; obtaining the first test voltage data at the moment when the voltmeter is currently connected by disconnecting and reconnecting the test voltmeter after the capacitor is fully charged; obtaining the insulation resistance of the capacitor according to the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor. The system includes modules corresponding to the steps of the method. The core idea of ​​the method is to measure the change of capacitor voltage within a specified time by utilizing the principle of self-discharge of the capacitor after charging, and make corrections to eliminate disturbances, so as to accurately determine the insulation resistance of the capacitor.

Description

Technical Field

[0001] The invention provides a method and system for testing the insulation resistance of a vehicle-mounted film capacitor, belonging to the technical field of capacitor insulation resistance testing. Background Art

[0002] The insulation resistance measurement methods of film capacitors have always been followed by each manufacturer using the two methods described below. Although these two methods seem to be correct, the power supply is not an ideal DC power supply in the actual test process, and contains a large amount of high and low frequency AC disturbance components. Capacitors have the basic characteristics of blocking DC and passing AC. During the insulation resistance measurement process, AC disturbance has a great impact on the result, resulting in the inability to correctly obtain the insulation resistance value of the capacitor. Summary of the invention

[0003] The present invention provides a method and system for testing the insulation resistance of a vehicle-mounted film capacitor, which is used to solve the problem that the insulation resistance test methods in the above two prior arts cannot correctly obtain the insulation resistance value of the capacitor, resulting in a large error in the insulation resistance value of the capacitor. The technical solution adopted is as follows:

[0004] A method for testing the insulation resistance of a vehicle-mounted film capacitor, the method comprising:

[0005] Charging the capacitor and recording the voltage data of the capacitor after charging is completed;

[0006] After the capacitor is fully charged, the first test voltage data at the moment when the test voltmeter is connected is obtained by disconnecting and reconnecting the test voltmeter;

[0007] The insulation resistance of a capacitor is determined based on its initial voltage, discharge time, voltage after discharge, and electrostatic capacity.

[0008] Further, charging the capacitor and recording the voltage data of the capacitor after charging is completed, including:

[0009] Continuously charging the capacitor;

[0010] Monitor the charging status of the charger in real time;

[0011] The voltage data of the capacitor is recorded after the capacitor is completely charged.

[0012] Further, the capacitor is continuously charged, including:

[0013] Setting a first charging voltage value;

[0014] The capacitor is charged using the first charging voltage value so that the charge amount of the capacitor reaches a first charge amount; wherein the first charge amount is obtained by the following formula;

[0015] in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 Indicates the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor;

[0016] When the charge amount of the capacitor reaches the first charge amount, the first charging voltage value is boosted to a second charging voltage value; wherein the second charging voltage value is a charging voltage corresponding to the maximum charging efficiency of the capacitor; and at the same time, the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54;

[0017] The capacitor is charged using the second charging voltage value until the capacitor is completely charged.

[0018] The voltage boost gradient of the first charging voltage value to the second charging voltage value with unit time as the change reference time is obtained by the following formula:

[0019]

[0020] in, V t Indicates the value of the boost gradient; V 01 and V 02 Respectively represent the voltage values ​​of the capacitor corresponding to the first charge and the full charge; n It indicates the number of unit times contained in the preset maximum excessive duration allowed for boost overcharging, and the value of the unit time is 1s.

[0021] Furthermore, after the capacitor is completely charged, the first test voltage data at the moment when the test voltmeter is currently connected is obtained by disconnecting and reconnecting the test voltmeter, including:

[0022] Set a specified duration; wherein the specified duration is obtained by the following formula:

[0023]

[0024] in, T Indicates the time value corresponding to the specified duration; T 0 Indicates the theoretical discharge time from when the capacitor is fully charged to when it is empty;

[0025] After the capacitor is fully charged, disconnect the test voltmeter and start timing;

[0026] When the timing reaches a specified time, the voltmeter is connected at the end of the specified time, and the first test voltage data at the current time when the voltmeter is connected is obtained.

[0027] Furthermore, the insulation resistance of the capacitor is obtained according to the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor, including:

[0028] Testing the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor;

[0029] Extracting the corresponding parameter information of the capacitor's initial voltage, discharge time, post-discharge voltage, and electrostatic capacity; wherein the discharge time is the specified duration; and the post-discharge voltage is the first test voltage data;

[0030] Using the capacitor's CR discharge circuit, the insulation resistance is estimated by combining four parameters: initial voltage, discharge time, voltage after discharge, and electrostatic capacitance.

[0031] A testing system for the insulation resistance of a vehicle-mounted film capacitor, the testing system for the insulation resistance of a vehicle-mounted film capacitor comprising:

[0032] A charging control module, used to charge the capacitor and record the voltage data of the capacitor after charging is completed;

[0033] A reconnection control module, used to obtain the first test voltage data at the moment when the voltmeter is currently connected by disconnecting and reconnecting the test voltmeter after the capacitor is completely charged;

[0034] The insulation resistance acquisition module is used to obtain the insulation resistance of a given capacitor based on the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor.

[0035] Furthermore, the charging control module includes:

[0036] A continuous charging control module, used for continuously charging the capacitor;

[0037] Real-time monitoring module, used to monitor the charging status of the charger in real time;

[0038] The voltage data recording module is used to record the voltage data of the capacitor after the capacitor is completely charged.

[0039] Furthermore, the continuous charging control module includes:

[0040] A first voltage setting module, used to set a first charging voltage value;

[0041] A first charging control module is used to charge the capacitor using the first charging voltage value so that the charge amount of the capacitor reaches a first electric quantity; wherein the first electric quantity is obtained by the following formula;

[0042]

[0043] in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 Indicates the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor;

[0044] A boost control module is used to boost the first charging voltage value to a second charging voltage value when the charge amount of the capacitor reaches the first charge amount; wherein the second charging voltage value is the charging voltage corresponding to the maximum charging efficiency of the capacitor; and at the same time, the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54;

[0045] The second charging control module is used to charge the capacitor using a second charging voltage value until the capacitor is completely charged.

[0046] The voltage boost gradient of the first charging voltage value to the second charging voltage value with unit time as the change reference time is obtained by the following formula:

[0047]

[0048] in, V t Indicates the value of the boost gradient; V 01 and V 02 Respectively represent the voltage values ​​of the capacitor corresponding to the first charge and the full charge; nIt indicates the number of unit times contained in the preset maximum excessive duration allowed for boost overcharging, and the value of the unit time is 1s.

[0049] Furthermore, the tie-back control module includes:

[0050] The duration setting module is used to set the specified duration; wherein the specified duration is obtained by the following formula:

[0051]

[0052] in, T Indicates the time value corresponding to the specified duration; T 0 Indicates the theoretical discharge time from when the capacitor is fully charged to when it is empty;

[0053] A timing control module, used to disconnect the test voltmeter after the capacitor is fully charged and to perform timing;

[0054] The first test voltage data acquisition module is used to connect the voltmeter at the end of the specified time when the timing reaches the specified time, and obtain the first test voltage data at the current time of connecting the voltmeter.

[0055] Furthermore, the insulation resistance acquisition module includes:

[0056] The electrostatic capacity test control module is used to test the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor;

[0057] A data extraction module is used to extract the corresponding parameter information of the initial voltage, discharge time, post-discharge voltage and electrostatic capacity of the capacitor; wherein the discharge time is the specified time; and the post-discharge voltage is the first test voltage data;

[0058] The resistance acquisition execution module is used to estimate the insulation resistance by using the CR discharge circuit of the capacitor and combining four parameters: initial voltage, discharge time, post-discharge voltage, and electrostatic capacitance.

[0059] Beneficial effects of the present invention:

[0060] The present invention proposes a method and system for testing the insulation resistance of a vehicle-mounted film capacitor to avoid the influence of low-frequency voltage disturbance from the high-voltage DC power supply itself on the test results. The core idea of ​​this method is to use the principle of self-discharge of the capacitor after charging, measure the change of the capacitor voltage within a specified time, and make corrections to eliminate the disturbance, so as to accurately measure the insulation resistance of the capacitor.

[0061] The present invention proposes a method and system for testing the insulation resistance of a vehicle-mounted film capacitor, which makes full use of the self-discharge characteristics of the capacitor. After charging, the capacitor will naturally release the stored charge, causing the voltage to gradually decrease. By recording the voltage change of the capacitor within a specified time, information about the insulation resistance of the capacitor can be obtained. The test result is adjusted according to the time constant CR of the capacitor self-discharge. The purpose of this is to ensure that the test value is consistent with the actual value, because the high-voltage DC power supply may introduce low-frequency voltage disturbances, resulting in inaccurate measurements. By calculating the CR value, the calculated value of the voltage after discharge can be corrected to eliminate the influence of the disturbance, thereby obtaining an accurate insulation resistance value. The present invention proposes a method and system for testing the insulation resistance of a vehicle-mounted film capacitor, which is directly measured by professional equipment such as the VI method or the bridge method. The electrostatic capacitance is an inherent property of a capacitor and usually does not change with changes in voltage unless damage occurs. Therefore, the C value is a stable reference point that can be accurately measured.

[0062] Therefore, the present invention proposes a method and system for testing the insulation resistance of vehicle-mounted film capacitors, which fully utilizes the self-discharge characteristics and electrostatic capacitance properties of capacitors. By measuring the change of capacitor voltage and correcting the CR value, the insulation resistance of vehicle-mounted film capacitors can be accurately measured without being disturbed by the low-frequency voltage disturbance of the high-voltage DC power supply itself, effectively improving the accuracy of the test and ensuring the safety and reliability of vehicle-mounted capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 is a flow chart of the method of the present invention;

[0064] Figure 2 is a system block diagram of the system of the present invention;

[0065] Figure 3 The waveform of the method of the present invention Figure 1 ;

[0066] Figure 4 The waveform of the method of the present invention Figure 2 ;

[0067] Figure 5 1 is a circuit structure diagram of the capacitor CR discharge circuit of the present invention;

[0068] (E, high-voltage DC power supply; R, current-limiting resistor; S1, first switch; S2, second switch; C, capacitor under test; V, voltmeter). DETAILED DESCRIPTION

[0069] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0070] The embodiment of the present invention provides a method for testing the insulation resistance of a vehicle-mounted film capacitor, such as Figure 1 As shown, the test method for the insulation resistance of the vehicle-mounted film capacitor includes:

[0071] S1, charging the capacitor and recording the voltage data of the capacitor after charging is completed;

[0072] S2, after the capacitor is fully charged, the test voltmeter is disconnected and reconnected to obtain the first test voltage data at the moment when the voltmeter is currently connected;

[0073] S3. Obtain the insulation resistance of the capacitor based on the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor.

[0074] The working principle of the above technical solution is: using the principle of self-discharge of capacitors after charging, measuring the voltage change of capacitors within a specified time, and using the CR time constant of the corrected capacitor self-discharge to make the calculated value of the voltage after discharge consistent with the measured value. In this way, the CR value can be uniquely determined. On the other hand, the electrostatic capacitance C of the capacitor can be directly tested using professional equipment such as the VI method and the bridge method, and the capacitance value does not change with the voltage change (in a non-destructive state), so C can be obtained. Therefore, R (i.e. insulation resistance, IR) is also uniquely determined.

[0075] Specific testing process:

[0076] Charge the capacitor and get the charging completion status. The voltage across the capacitor reaches the test voltage and the voltage data is recorded.

[0077] Start timing after disconnecting the test voltmeter;

[0078] After the specified time has elapsed, connect the voltmeter and quickly read out the first measured data;

[0079] Test the electrostatic capacity of capacitors

[0080] According to the capacitor CR discharge circuit (capacitor CR discharge circuit as shown Figure 5 As shown), the insulation resistance is estimated by combining the initial voltage, discharge time, voltage after discharge, and electrostatic capacitance;

[0081] Close S1 / S2, E charges the capacitor through the current limiting resistor, and V reads the voltage parameter until the voltage across the capacitor is the same as the voltage across the power supply;

[0082] Record the voltage across the capacitor as the initial voltage;

[0083] Turn on S2 first, then turn on S1 (the order cannot be changed here), and start timing when S1 is turned on;

[0084] After reaching the preset discharge time, S2 is closed, and voltage measurement is started 10-50ms after S2 is closed. The first voltage read is the discharge termination voltage.

[0085] The insulation resistance of the capacitor is estimated based on the predicted electrostatic capacitance, discharge time, and discharge start / end voltage.

[0086] like Figure 3 The following is an example of calculation results: For a long-term discharge curve, you only need to know the discharge start and end voltages, discharge time, and capacitance, and then the entire discharge curve and insulation resistance can be calculated.

[0087] If it is to be used in production, the discharge time can be shortened, and rapid measurement can be performed under the condition that the voltmeter can effectively measure. Figure 4 shown.

[0088] The effect of the above technical solution is: the test method for the insulation resistance of the vehicle-mounted film capacitor proposed in this embodiment avoids the influence of the low-frequency voltage disturbance from the high-voltage DC power supply itself on the test result. The core idea of ​​this method is to measure the change of the capacitor voltage within a specified time by utilizing the principle of self-discharge after the capacitor is charged, and make corrections to eliminate the disturbance, so as to accurately measure the insulation resistance of the capacitor.

[0089] A test method for the insulation resistance of a vehicle-mounted film capacitor proposed in this embodiment makes full use of the self-discharge characteristics of the capacitor. After charging, the capacitor will naturally release the stored charge, causing the voltage to gradually decrease. By recording the voltage change of the capacitor within a specified time, information about the insulation resistance of the capacitor can be obtained. The test result is adjusted according to the time constant CR of the capacitor self-discharge. The purpose of this is to ensure that the test value is consistent with the actual value, because the high-voltage DC power supply may introduce low-frequency voltage disturbances, resulting in inaccurate measurements. By calculating the CR value, the calculated value of the voltage after discharge can be corrected to eliminate the influence of the disturbance, thereby obtaining an accurate insulation resistance value. A test method for the insulation resistance of a vehicle-mounted film capacitor proposed in this embodiment is directly measured by professional equipment such as the VI method or the bridge method. The electrostatic capacitance is an inherent property of a capacitor and usually does not change with changes in voltage unless damage occurs. Therefore, the C value is a stable reference point that can be accurately measured.

[0090] Therefore, the test method for the insulation resistance of the on-board film capacitor proposed in this embodiment makes full use of the self-discharge characteristics and electrostatic capacitance properties of the capacitor. By measuring the change of the capacitor voltage and correcting the CR value, the insulation resistance of the on-board film capacitor can be accurately measured without being disturbed by the low-frequency voltage disturbance of the high-voltage DC power supply itself. The accuracy of the test is effectively improved to ensure the safety and reliability of the on-board capacitor.

[0091] In one embodiment of the present invention, charging a capacitor and recording voltage data of the capacitor after charging is completed includes:

[0092] S101, continuously charging the capacitor;

[0093] S102, monitoring the charging status of the charger in real time;

[0094] S103, recording the voltage data of the capacitor after the capacitor is completely charged.

[0095] The capacitor is continuously charged, including:

[0096] S1011, setting a first charging voltage value;

[0097] S1012. Charge the capacitor using the first charging voltage value so that the charge amount of the capacitor reaches a first charge amount; wherein the first charge amount is obtained by the following formula;

[0098]

[0099] in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 Indicates the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor;

[0100] S1013. When the charge amount of the capacitor reaches the first charge amount, the first charging voltage value is boosted to a second charging voltage value; wherein the second charging voltage value is a charging voltage corresponding to the maximum charging efficiency of the capacitor; and the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54;

[0101] S1014. Charge the capacitor using the second charging voltage value until the capacitor is fully charged.

[0102] The voltage boost gradient of the first charging voltage value to the second charging voltage value with unit time as the change reference time is obtained by the following formula:

[0103]

[0104] in, V t Indicates the value of the boost gradient; V 01 and V 02 Respectively represent the voltage values ​​of the capacitor corresponding to the first charge and the full charge; n It indicates the number of unit times contained in the preset maximum excessive duration allowed for boost overcharging, and the value of the unit time is 1s.

[0105] The working principle of the above technical solution is: Continuous charging (S101): firstly, the capacitor is continuously charged.

[0106] Real-time monitoring of charging status (S102): The charging status of the charger is monitored in real time to understand the charging process of the capacitor.

[0107] Recording voltage data of the capacitor (S103): After the capacitor is fully charged, the voltage data of the capacitor is recorded for use in a subsequent insulation resistance test.

[0108] The following is a detailed explanation of the steps for continuous charging:

[0109] Setting a first charging voltage value (S1011): First, an initial charging voltage value is set, which is used for charging in the initial stage.

[0110] Charging to a first charge (S1012): The capacitor is charged using a first charging voltage value until the charge amount of the capacitor reaches a set first charge amount. The first charge amount is calculated by a formula, which includes factors such as the initial charge amount of the capacitor, the multiple adjustment coefficient, a constant, and the fully charged charge amount of the capacitor.

[0111] Boosting to a second charging voltage value (S1013): Once the charge amount of the capacitor reaches the first charge amount, the first charging voltage value is boosted to a second charging voltage value. The second charging voltage value is set to achieve maximum charging efficiency, and the value range of the first charging voltage value is constrained by the multiple adjustment coefficient P.

[0112] Charging until the capacitor is completely charged (S1014): charging the capacitor using the second charging voltage value until the capacitor is completely charged.

[0113] The calculation of the boost gradient (in S1013) is determined according to a certain formula, taking into account factors such as the capacitor voltage value, the number of unit times included in the preset maximum excess time allowed for boost overcharging, and the like.

[0114] The above technical solution of this embodiment gradually fills the capacitor by continuous charging and achieves maximum charging efficiency by boosting the voltage to the second charging voltage value. The calculation method of the first charging voltage value and the boost gradient ensures that the capacitor will not be overcharged during the charging process, thereby improving safety.

[0115] The effect of the above technical solution is: by boosting the voltage to the second charging voltage value to achieve maximum charging efficiency, thereby reducing charging time and energy consumption. By limiting overcharging during the charging process, the capacitor is protected from the risk of damage or overheating. By continuously charging and recording voltage data, the accuracy of insulation resistance testing can be improved to ensure reliable test results.

[0116] The above technical solution of this embodiment aims to improve the charging efficiency and test accuracy of the capacitor by accurately controlling the charging process, while protecting the safety of the capacitor. This is very useful for the insulation resistance test of the vehicle-mounted film capacitor.

[0117] At the same time, by using the above formula, the required capacitor charge (first charge) can be accurately calculated at the beginning of charging. This helps to ensure that overcharging does not occur during the charging process, thereby improving the accuracy and safety of charging. The ΔE in the formula represents the increase in the charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor. By considering the maximum charging efficiency, the charging time and energy consumption can be reduced, and the charging efficiency can be improved. The formula includes the multiple adjustment coefficient P and the constant e, which can be adjusted according to specific applications and requirements to achieve adaptive charging control. This means that the charging process can be customized according to different situations to meet specific needs. By calculating the first charge, the charging process of the capacitor can be wisely controlled to prevent overcharging, thereby reducing the potential risks of overcharging to the capacitor, such as damage or overheating. The technical effect of the above formula is to achieve precise control and maximum charging efficiency of the capacitor charging process, while taking into account adaptability, which helps to improve the efficiency and safety of charging and ensure the best performance and maintenance of the capacitor during the charging process.

[0118] On the other hand, the above formula of this embodiment can be used to calculate the rate of increase of the capacitor voltage per unit time (boost gradient). This makes it possible to accurately control the rate of increase of the voltage during the capacitor charging process to ensure that the charging is not too fast or too slow, thereby improving the controllability and stability of the charging process. The formula includes the preset maximum excessive duration of the allowed boost overcharge and the number of unit times. This means that a safe time window can be set within which the capacitor voltage can gradually increase to the target value without overcharging, thereby reducing the risk of capacitor damage or overheating. By controlling the boost gradient, the capacitor can be better protected from unnecessary voltage shocks, its service life can be extended, and its stability and reliability can be improved.

[0119] In summary, the technical solution of this embodiment provides an effective way to control the voltage boost rate during capacitor charging to ensure safe and controllable charging, reduce the risk of overcharging, and help protect and maintain the capacitor. This is very important for the charging process in applications such as automotive film capacitors.

[0120] In one embodiment of the present invention, after the capacitor is fully charged, the first test voltage data at the moment when the test voltmeter is currently connected is obtained by disconnecting and reconnecting the test voltmeter, including:

[0121] S201, setting a prescribed duration; wherein the prescribed duration is obtained by the following formula:

[0122]

[0123] in, T Indicates the time value corresponding to the specified duration; T 0 Indicates the theoretical discharge time from when the capacitor is fully charged to when it is empty;

[0124] S202, disconnecting the test voltmeter after the capacitor is fully charged, and starting timing;

[0125] S203, when the timing reaches a specified time, the voltmeter is connected at the end of the specified time, and the first test voltage data at the current time of connecting the voltmeter is obtained.

[0126] The working principle of the above technical solution is as follows: Setting a prescribed time length (S201): First, a prescribed time length is set to control the test time length. The prescribed time length is calculated by a formula, which takes into account the theoretical discharge time length (T0) of the capacitor from full charge to empty charge.

[0127] Disconnecting the test voltmeter and starting timing ( S202 ): After the capacitor is completely charged, disconnecting the test voltmeter and starting timing.

[0128] Waiting for a specified time (S203): Before the timing reaches the specified time (T), the capacitor is kept in a disconnected state. This waiting process is to simulate the test conditions of the capacitor insulation resistance.

[0129] Connecting the voltmeter and acquiring the first test voltage data (S203): When the timing reaches a specified time, the voltmeter is connected again to acquire the first test voltage data at the current moment when the voltmeter is connected.

[0130] The effect of the above technical solution is: this embodiment uses a specified waiting time (specified duration) to simulate the test conditions of the capacitor insulation resistance. During the waiting period, the capacitor is in a disconnected state and is not connected to the test voltmeter. Then, at the end of the specified duration, the voltmeter is connected again to obtain the first test voltage data of the capacitor.

[0131] The technical effect of this method is to control the timing of the test by a specified waiting time to ensure the accuracy of the test. The waiting time is calculated based on the theoretical discharge time (T0) of the capacitor from full charge to empty charge, which helps to ensure that the test conditions are consistent, thereby obtaining reliable test results. This method can avoid the influence of the low-frequency voltage disturbance of the high-voltage DC power supply on the test results, improve the accuracy and repeatability of the test, and is particularly suitable for capacitor insulation resistance testing.

[0132] In one embodiment of the present invention, the insulation resistance of a capacitor is obtained according to the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor, including:

[0133] S301, testing the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor;

[0134] S302, extracting corresponding parameter information of the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor; wherein the discharge time is the specified time; the voltage after discharge is the first test voltage data;

[0135] S303. Use the CR discharge circuit of the capacitor to estimate the insulation resistance by combining the four parameters of initial voltage, discharge time, voltage after discharge, and electrostatic capacitance.

[0136] The working principle of the above technical solution is: testing the electrostatic capacity of the capacitor (S301): first, testing the electrostatic capacity of the capacitor to obtain the electrostatic capacity value of the capacitor. Electrostatic capacity is a basic parameter of a capacitor, indicating its ability to store charge.

[0137] Extract parameter information (S302): Extract information of four parameters, namely, initial voltage, discharge time, voltage after discharge and electrostatic capacity, from the capacitor. These parameters will be used for subsequent insulation resistance calculation.

[0138] Insulation resistance calculation (S303): Using the CR discharge circuit of the capacitor and the extracted parameter information, the insulation resistance is calculated by combining the four parameters of initial voltage, discharge time, voltage after discharge and electrostatic capacitance. Insulation resistance is a key indicator of the insulation performance of the capacitor, which can be obtained by combining these parameters.

[0139] The effect of the above technical solution is: the method measures the electrostatic capacity of the capacitor and extracts parameter information, combines the CR discharge circuit, and uses parameters such as initial voltage, discharge time, voltage after discharge and electrostatic capacity to estimate the insulation resistance of the capacitor. The CR discharge circuit is a common circuit for measuring the insulation resistance of capacitors. It calculates the insulation resistance by measuring the discharge time and voltage change of the capacitor.

[0140] The technical effect of the method proposed in this embodiment is that the insulation resistance of the capacitor can be estimated by measuring simple electrostatic capacitance and several key voltage and time parameters. This can achieve a rapid assessment of the insulation performance of the capacitor without the need for complex testing equipment, thereby improving the efficiency and convenience of the test. At the same time, since insulation resistance is one of the important indicators of capacitor performance, this method helps to detect potential insulation problems early and perform maintenance.

[0141] The embodiment of the present invention provides a testing system for the insulation resistance of a vehicle-mounted film capacitor, such as Figure 2 As shown, the test system for the insulation resistance of the vehicle-mounted film capacitor includes:

[0142] A charging control module, used to charge the capacitor and record the voltage data of the capacitor after charging is completed;

[0143] A reconnection control module, used to obtain the first test voltage data at the moment when the voltmeter is currently connected by disconnecting and reconnecting the test voltmeter after the capacitor is completely charged;

[0144] The insulation resistance acquisition module is used to obtain the insulation resistance of a given capacitor based on the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor.

[0145] The working principle of the above technical solution is: using the principle of self-discharge of capacitors after charging, measuring the voltage change of capacitors within a specified time, and using the CR time constant of the corrected capacitor self-discharge to make the calculated value of the voltage after discharge consistent with the measured value. In this way, the CR value can be uniquely determined. On the other hand, the electrostatic capacitance C of the capacitor can be directly tested using professional equipment such as the VI method and the bridge method, and the capacitance value does not change with the voltage change (in a non-destructive state), so C can be obtained. Therefore, R (i.e. insulation resistance, IR) is also uniquely determined.

[0146] Specific testing process:

[0147] Charge the capacitor and get the charging completion status. The voltage across the capacitor reaches the test voltage and the voltage data is recorded.

[0148] Start timing after disconnecting the test voltmeter;

[0149] After the specified time has elapsed, connect the voltmeter and quickly read out the first measured data;

[0150] Test the electrostatic capacity of capacitors

[0151] According to the capacitor CR discharge circuit (capacitor CR discharge circuit as shown Figure 5 As shown), the insulation resistance is estimated by combining the initial voltage, discharge time, voltage after discharge, and electrostatic capacitance;

[0152] Close S1 / S2, E charges the capacitor through the current limiting resistor, and V reads the voltage parameter until the voltage across the capacitor is the same as the voltage across the power supply;

[0153] Record the voltage across the capacitor as the initial voltage;

[0154] Turn on S2 first, then turn on S1 (the order cannot be changed here), and start timing when S1 is turned on;

[0155] After reaching the preset discharge time, S2 is closed, and voltage measurement is started 10-50ms after S2 is closed. The first voltage read is the discharge termination voltage.

[0156] The insulation resistance of the capacitor is estimated based on the predicted electrostatic capacitance, discharge time, and discharge start / end voltage.

[0157] like Figure 3 The following is an example of calculation results: For a long-term discharge curve, you only need to know the discharge start and end voltages, discharge time, and capacitance, and then the entire discharge curve and insulation resistance can be calculated.

[0158] If it is to be used in production, the discharge time can be shortened, and rapid measurement can be performed under the condition that the voltmeter can effectively measure. Figure 4shown.

[0159] The effect of the above technical solution is: the test system for the insulation resistance of the vehicle-mounted film capacitor proposed in this embodiment avoids the influence of the low-frequency voltage disturbance from the high-voltage DC power supply itself on the test results. The core idea of ​​this method is to measure the change of the capacitor voltage within a specified time by utilizing the principle of self-discharge after the capacitor is charged, and make corrections to eliminate the disturbance, so as to accurately measure the insulation resistance of the capacitor.

[0160] A test system for the insulation resistance of a vehicle-mounted film capacitor proposed in this embodiment makes full use of the self-discharge characteristics of the capacitor. After charging, the capacitor will naturally release the stored charge, causing the voltage to gradually decrease. By recording the voltage change of the capacitor within a specified time, information about the insulation resistance of the capacitor can be obtained. The test result is adjusted according to the time constant CR of the capacitor self-discharge. The purpose of this is to ensure that the test value is consistent with the actual value, because the high-voltage DC power supply may introduce low-frequency voltage disturbances, resulting in inaccurate measurements. By calculating the CR value, the calculated value of the voltage after discharge can be corrected to eliminate the influence of the disturbance, thereby obtaining an accurate insulation resistance value. A test system for the insulation resistance of a vehicle-mounted film capacitor proposed in this embodiment is directly measured by professional equipment such as the VI method or the bridge method. The electrostatic capacitance is an inherent property of a capacitor and usually does not change with changes in voltage unless damage occurs. Therefore, the C value is a stable reference point that can be accurately measured.

[0161] Therefore, the test system for the insulation resistance of the on-board film capacitor proposed in this embodiment makes full use of the self-discharge characteristics and electrostatic capacitance properties of the capacitor, and can accurately measure the insulation resistance of the on-board film capacitor by measuring the change of the capacitor voltage and correcting the CR value without being disturbed by the low-frequency voltage disturbance of the high-voltage DC power supply itself, effectively improving the accuracy of the test and ensuring the safety and reliability of the on-board capacitor.

[0162] In one embodiment of the present invention, the charging control module includes:

[0163] A continuous charging control module, used for continuously charging the capacitor;

[0164] Real-time monitoring module, used to monitor the charging status of the charger in real time;

[0165] The voltage data recording module is used to record the voltage data of the capacitor after the capacitor is completely charged.

[0166] Wherein, the continuous charging control module includes:

[0167] A first voltage setting module, used to set a first charging voltage value;

[0168] A first charging control module is used to charge the capacitor using the first charging voltage value so that the charge amount of the capacitor reaches a first electric quantity; wherein the first electric quantity is obtained by the following formula;

[0169]

[0170] in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 Indicates the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor;

[0171] A boost control module is used to boost the first charging voltage value to a second charging voltage value when the charge amount of the capacitor reaches the first charge amount; wherein the second charging voltage value is the charging voltage corresponding to the maximum charging efficiency of the capacitor; and at the same time, the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54;

[0172] The second charging control module is used to charge the capacitor using a second charging voltage value until the capacitor is completely charged.

[0173] The voltage boost gradient of the first charging voltage value to the second charging voltage value with unit time as the change reference time is obtained by the following formula:

[0174]

[0175] in, V t Indicates the value of the boost gradient; V 01 and V 02 Respectively represent the voltage values ​​of the capacitor corresponding to the first charge and the full charge; n It indicates the number of unit times contained in the preset maximum excessive duration allowed for boost overcharging, and the value of the unit time is 1s.

[0176] The working principle of the above technical solution is: first, the capacitor is continuously charged. The charging state of the charger is monitored in real time to understand the charging process of the capacitor. When the capacitor is fully charged, the voltage data of the capacitor is recorded for subsequent insulation resistance testing.

[0177] The following is a detailed explanation of the steps for continuous charging:

[0178] First, an initial charging voltage value is set, which is used for charging in the initial stage.

[0179] The capacitor is charged using the first charging voltage value until the charged amount of the capacitor reaches the set first charge. The calculation of the first charge is determined by a formula, which includes factors such as the initial charge of the capacitor, the multiple adjustment coefficient, the constant, and the fully charged charge of the capacitor.

[0180] Once the charge amount of the capacitor reaches the first charge amount, the first charging voltage value is boosted to a second charging voltage value. The second charging voltage value is set to achieve maximum charging efficiency, and the value range of the first charging voltage value is constrained by the multiple adjustment coefficient P.

[0181] The capacitor is charged using the second charging voltage value until the capacitor is completely charged.

[0182] The calculation of the boost gradient is determined according to a certain formula, taking into account factors such as the capacitor voltage value, the number of unit times contained in the preset maximum excess time allowed for boost overcharging, and so on.

[0183] The above technical solution of this embodiment gradually fills the capacitor by continuous charging and achieves maximum charging efficiency by boosting the voltage to the second charging voltage value. The calculation method of the first charging voltage value and the boost gradient ensures that the capacitor will not be overcharged during the charging process, thereby improving safety.

[0184] The effect of the above technical solution is: by boosting the voltage to the second charging voltage value to achieve maximum charging efficiency, thereby reducing charging time and energy consumption. By limiting overcharging during the charging process, the capacitor is protected from the risk of damage or overheating. By continuously charging and recording voltage data, the accuracy of insulation resistance testing can be improved to ensure reliable test results.

[0185] The above technical solution of this embodiment aims to improve the charging efficiency and test accuracy of the capacitor by accurately controlling the charging process, while protecting the safety of the capacitor. This is very useful for the insulation resistance test of the vehicle-mounted film capacitor.

[0186] At the same time, by using the above formula, the required capacitor charge (first charge) can be accurately calculated at the beginning of charging. This helps to ensure that overcharging does not occur during the charging process, thereby improving the accuracy and safety of charging. The ΔE in the formula represents the increase in the charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor. By considering the maximum charging efficiency, the charging time and energy consumption can be reduced, and the charging efficiency can be improved. The formula includes the multiple adjustment coefficient P and the constant e, which can be adjusted according to specific applications and requirements to achieve adaptive charging control. This means that the charging process can be customized according to different situations to meet specific needs. By calculating the first charge, the charging process of the capacitor can be wisely controlled to prevent overcharging, thereby reducing the potential risks of overcharging to the capacitor, such as damage or overheating. The technical effect of the above formula is to achieve precise control and maximum charging efficiency of the capacitor charging process, while taking into account adaptability, which helps to improve the efficiency and safety of charging and ensure the best performance and maintenance of the capacitor during the charging process.

[0187] On the other hand, the above formula of this embodiment can be used to calculate the rate of increase of the capacitor voltage per unit time (boost gradient). This makes it possible to accurately control the rate of increase of the voltage during the capacitor charging process to ensure that the charging is not too fast or too slow, thereby improving the controllability and stability of the charging process. The formula includes the preset maximum excessive duration of the allowed boost overcharge and the number of unit times. This means that a safe time window can be set within which the capacitor voltage can gradually increase to the target value without overcharging, thereby reducing the risk of capacitor damage or overheating. By controlling the boost gradient, the capacitor can be better protected from unnecessary voltage shocks, its service life can be extended, and its stability and reliability can be improved.

[0188] In summary, the technical solution of this embodiment provides an effective way to control the voltage boost rate during capacitor charging to ensure safe and controllable charging, reduce the risk of overcharging, and help protect and maintain the capacitor. This is very important for the charging process in applications such as automotive film capacitors.

[0189] In one embodiment of the present invention, the connection back control module includes:

[0190] The duration setting module is used to set the specified duration; wherein the specified duration is obtained by the following formula:

[0191]

[0192] in, T Indicates the time value corresponding to the specified duration; T0 Indicates the theoretical discharge time from when the capacitor is fully charged to when it is empty;

[0193] A timing control module, used to disconnect the test voltmeter after the capacitor is fully charged and to perform timing;

[0194] The first test voltage data acquisition module is used to connect the voltmeter at the end of the specified time when the timing reaches the specified time, and obtain the first test voltage data at the current time of connecting the voltmeter.

[0195] The working principle of the above technical solution is as follows: first, a specified time length is set to control the test duration. This specified time length is calculated by a formula, which takes into account the theoretical discharge time (T0) of the capacitor from full charge to empty charge.

[0196] After the capacitor has finished charging, disconnect the test voltmeter and start timing.

[0197] The capacitor is kept disconnected until the timing reaches the specified time (T). This waiting process is to simulate the test conditions of the capacitor insulation resistance.

[0198] When the timing reaches the specified time, the voltmeter is connected again to obtain the first test voltage data at the current moment when the voltmeter is connected.

[0199] The effect of the above technical solution is: this embodiment uses a specified waiting time (specified duration) to simulate the test conditions of the capacitor insulation resistance. During the waiting period, the capacitor is in a disconnected state and is not connected to the test voltmeter. Then, at the end of the specified duration, the voltmeter is connected again to obtain the first test voltage data of the capacitor.

[0200] The technical effect of this method is to control the timing of the test by a specified waiting time to ensure the accuracy of the test. The waiting time is calculated based on the theoretical discharge time (T0) of the capacitor from full charge to empty charge, which helps to ensure that the test conditions are consistent, thereby obtaining reliable test results. This method can avoid the influence of the low-frequency voltage disturbance of the high-voltage DC power supply on the test results, improve the accuracy and repeatability of the test, and is particularly suitable for capacitor insulation resistance testing.

[0201] In one embodiment of the present invention, the insulation resistance acquisition module includes:

[0202] The electrostatic capacity test control module is used to test the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor;

[0203] A data extraction module is used to extract the corresponding parameter information of the initial voltage, discharge time, post-discharge voltage and electrostatic capacity of the capacitor; wherein the discharge time is the specified time; and the post-discharge voltage is the first test voltage data;

[0204] The resistance acquisition execution module is used to estimate the insulation resistance by using the CR discharge circuit of the capacitor and combining four parameters: initial voltage, discharge time, post-discharge voltage, and electrostatic capacitance.

[0205] The working principle of the above technical solution is as follows: first, the electrostatic capacitance of the capacitor is tested to obtain the electrostatic capacitance value of the capacitor. Electrostatic capacitance is a basic parameter of a capacitor, indicating its ability to store charge.

[0206] Extract information about the four parameters of initial voltage, discharge time, voltage after discharge, and electrostatic capacity from the capacitor. These parameters will be used in the subsequent insulation resistance calculation.

[0207] Using the capacitor's CR discharge circuit and extracted parameter information, the insulation resistance is calculated by combining the initial voltage, discharge time, voltage after discharge, and electrostatic capacitance. Insulation resistance is a key indicator of capacitor insulation performance and can be obtained by combining these parameters.

[0208] The effect of the above technical solution is: the method measures the electrostatic capacity of the capacitor and extracts parameter information, combines the CR discharge circuit, and uses parameters such as initial voltage, discharge time, voltage after discharge and electrostatic capacity to estimate the insulation resistance of the capacitor. The CR discharge circuit is a common circuit for measuring the insulation resistance of capacitors. It calculates the insulation resistance by measuring the discharge time and voltage change of the capacitor.

[0209] The technical effect of the method proposed in this embodiment is that the insulation resistance of the capacitor can be estimated by measuring simple electrostatic capacitance and several key voltage and time parameters. This can achieve a rapid assessment of the insulation performance of the capacitor without the need for complex testing equipment, thereby improving the efficiency and convenience of the test. At the same time, since insulation resistance is one of the important indicators of capacitor performance, this method helps to detect potential insulation problems early and perform maintenance.

[0210] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for testing the insulation resistance of a vehicle-mounted film capacitor, characterized in that: The test method for the insulation resistance of the vehicle-mounted film capacitor includes: Charging the capacitor and recording the voltage data of the capacitor after charging is completed; After the capacitor is fully charged, the first test voltage data at the moment when the test voltmeter is connected is obtained by disconnecting and reconnecting the test voltmeter; Obtain the insulation resistance of a capacitor based on its initial voltage, discharge time, voltage after discharge and electrostatic capacity; Charge the capacitor and record the voltage data of the capacitor after charging is completed, including: Continuously charging the capacitor; Monitor the charging status of the charger in real time; recording the voltage data of the capacitor after the capacitor is fully charged; Continuous charging of capacitors, including: Setting a first charging voltage value; The capacitor is charged using the first charging voltage value so that the charge amount of the capacitor reaches a first charge amount; wherein the first charge amount is obtained by the following formula; ； in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 represents the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor; When the charge amount of the capacitor reaches the first charge amount, the first charging voltage value is boosted to a second charging voltage value; wherein the second charging voltage value is a charging voltage corresponding to the maximum charging efficiency of the capacitor; and at the same time, the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54; The capacitor is charged using the second charging voltage value until the capacitor is completely charged.

2. The method for testing the insulation resistance of a vehicle-mounted film capacitor according to claim 1, characterized in that: After the capacitor is fully charged, the first test voltage data at the moment when the test voltmeter is connected is obtained by disconnecting and reconnecting the test voltmeter, including: Set a set duration; After the capacitor is fully charged, disconnect the test voltmeter and start timing; When the timing reaches a specified time, the voltmeter is connected at the end of the specified time, and the first test voltage data at the current time when the voltmeter is connected is obtained.

3. The method for testing the insulation resistance of a vehicle-mounted film capacitor according to claim 1, characterized in that: The insulation resistance of a capacitor is determined based on the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor, including: Testing the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor; Extracting the corresponding parameter information of the capacitor's initial voltage, discharge time, post-discharge voltage, and electrostatic capacity; wherein the discharge time is the specified duration; and the post-discharge voltage is the first test voltage data; Using the capacitor's CR discharge circuit, the insulation resistance is estimated by combining four parameters: initial voltage, discharge time, voltage after discharge, and electrostatic capacitance.

4. A test system for insulation resistance of vehicle-mounted film capacitors, characterized in that: The test system for the insulation resistance of a vehicle-mounted film capacitor comprises: A charging control module, used to charge the capacitor and record the voltage data of the capacitor after charging is completed; A reconnection control module, used to obtain the first test voltage data at the moment when the voltmeter is currently connected by disconnecting and reconnecting the test voltmeter after the capacitor is completely charged; The insulation resistance acquisition module is used to obtain the insulation resistance of a given capacitor according to the initial voltage, discharge time, voltage after discharge and electrostatic capacity of the capacitor; The charging control module comprises: A continuous charging control module, used for continuously charging the capacitor; Real-time monitoring module, used to monitor the charging status of the charger in real time; A voltage data recording module, used for recording voltage data of the capacitor after the capacitor is fully charged; The continuous charging control module includes: A first voltage setting module, used to set a first charging voltage value; A first charging control module is used to charge the capacitor using the first charging voltage value so that the charge amount of the capacitor reaches a first charge amount; wherein the first charge amount is obtained by the following formula; ； in, E 01 Indicates the first electrical quantity; P Indicates the multiple adjustment factor; e represents a constant; E 0 represents the initial charge of the capacitor; Δ E It indicates the increase in the amount of charge per unit time of the capacitor when charging at the charging voltage corresponding to the maximum charging efficiency of the capacitor; E Indicates the amount of electricity corresponding to a fully charged capacitor; A boost control module is used to boost the first charging voltage value to a second charging voltage value when the charge amount of the capacitor reaches the first charge amount; wherein the second charging voltage value is the charging voltage corresponding to the maximum charging efficiency of the capacitor; and at the same time, the value range of the first charging voltage value is P times the second charging voltage value, and, P The value range is 0.46-0.54; The second charging control module is used to charge the capacitor using a second charging voltage value until the capacitor is completely charged.

5. The test system for the insulation resistance of a vehicle-mounted film capacitor according to claim 4, characterized in that: The tie-back control module comprises: Duration setting module, used to set the specified duration; A timing control module, used to disconnect the test voltmeter after the capacitor is fully charged and to perform timing; The first test voltage data acquisition module is used to connect the voltmeter at the end of the specified time when the timing reaches the specified time, and obtain the first test voltage data at the current time when the voltmeter is connected.

6. The test system for the insulation resistance of a vehicle-mounted film capacitor according to claim 4, characterized in that: The insulation resistance acquisition module comprises: The electrostatic capacity test control module is used to test the electrostatic capacity of the capacitor to obtain the electrostatic capacity of the capacitor; A data extraction module is used to extract the corresponding parameter information of the initial voltage, discharge time, post-discharge voltage and electrostatic capacity of the capacitor; wherein the discharge time is the specified time; and the post-discharge voltage is the first test voltage data; The resistance acquisition execution module is used to estimate the insulation resistance by using the CR discharge circuit of the capacitor and combining four parameters: initial voltage, discharge time, post-discharge voltage, and electrostatic capacitance.

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