An insulation detection and abnormal position judgment method suitable for an energy storage converter

Abstract

The application provides an insulation detection and abnormal position judgment method suitable for an energy storage converter, which comprises the following steps: step 1, after the energy storage converter AC-DC plastic casing circuit breaker is closed, the internal control system auxiliary power supply is completed; step 2, the working state of the current energy storage converter is detected, if the current is in a non-stop state or the battery voltage detection value is not greater than the set threshold value, no insulation detection related operation is performed; if the current is in a stop state and the battery voltage value is greater than the set threshold value, the next step is entered, and insulation impedance value calculation is performed; through the optimized insulation impedance detection circuit and the multiple software filtering method, whether there is insulation abnormality is detected, and whether the abnormal point is located in the converter is judged according to the DC current difference at the positive pole inlet and the negative pole outlet of the DC side.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of insulation detection, and in particular to an insulation detection and abnormal position judgment method suitable for an energy storage converter. BACKGROUND

[0002] To solve the problem that the insulation impedance value detection fluctuates greatly and is inaccurate in the existing detection method, and the insulation impedance abnormal point cannot be determined to be located inside the energy storage converter or outside the battery system. SUMMARY

[0003] In order to solve the problems in the prior art, the present application provides an insulation detection and abnormal position judgment method suitable for an energy storage converter.

[0004] In order to solve the above technical problems, the present application provides the following technical scheme:

[0005] An insulation detection and abnormal position judgment method suitable for an energy storage converter, comprising the following steps:

[0006] Step 1, after the AC-DC molded case circuit breaker of the energy storage converter is closed, the internal control system is powered off for auxiliary power supply;

[0007] Step 2, the working state of the current energy storage converter is detected, if the current is in a non-stop state or the battery voltage detection value is not greater than the set threshold value, no insulation detection related operation is performed, if the current is in a stop state and the battery voltage value is greater than the set threshold value, the next step is entered to calculate the insulation impedance value;

[0008] Step 3, the insulation impedance value calculation module is entered to calculate the insulation impedance value of the positive electrode of the battery to PE and the insulation impedance value of the negative electrode of the battery to PE;

[0009] Step 4, the smaller value between the insulation impedance values of the positive electrode and the negative electrode to PE and the impedance threshold value are judged, if the smaller impedance value is not smaller than the impedance threshold value, the insulation is normal, and the next detection is directly returned to step 2, if the smaller impedance value is smaller than the impedance threshold value, the next step is entered;

[0010] Step 5, if the insulation alarm processing method set by the system is fault shutdown, the energy storage converter directly enters the fault state, and this method will not judge the position of the abnormal point, if the insulation alarm processing method set by the system is only alarm without shutdown, the next step is continued;

[0011] Step 6, whether the system is in a charging or discharging state is detected, if not, the power instruction is continued to be waited in the current state, if yes, the next step is entered;

[0012] Step 7, entering the DC positive and negative electrode current processing module, obtaining the filtered positive and negative electrode current values Idc_Filter_P and Idc_Filter_N; calculating the difference value delta_Idc of the two values;

[0013] Step 8, if the delta_Idc is greater than the DC threshold value, it is determined that the insulation impedance abnormal point is located inside the energy storage converter; otherwise, it is determined that the insulation impedance abnormal point is located outside the energy storage converter.

[0014] As a further technical solution of the application: the insulation impedance value calculation module is realized by an insulation impedance value detection circuit, which includes resistors R1, R2, R3, R4, relay contact switches K1 and K2, one end of the resistor R1 is connected with the resistor R2 and the relay contact switch K1, the other end of the resistor R2 is connected with the battery positive electrode BAT+, the other end of the resistor R1 is connected with the relay contact switch K1 and the resistor R3, the other end of the resistor R3 is connected with the PE sampling circuit and the resistor R6, one end of the resistor R4 is connected with the resistor R5 and the relay contact switch K2, the other end of the resistor R5 is connected with the battery negative electrode BAT-, the other end of the resistor R4 is connected with the relay contact switch K2 and the other end of the resistor R6.

[0015] As a further technical solution of the application: the resistance R1 has the same resistance value as the resistance R4, the resistance R2 has the same resistance value as the resistance R5, and the resistance R3 has the same resistance value as the resistance R6.

[0016] As a further technical solution of the application: inside the energy storage converter, a Hall current sensor is installed at the outer end position of the DC load switch, respectively at the positive electrode and the negative electrode of the battery, for detecting the DC current signals flowing through the positive electrode of the energy storage converter and the negative electrode of the energy storage converter.

[0017] As a further technical solution of the application: the calculation method of the insulation impedance is as follows:

[0018] Step 3.1, in the shutdown state, if the battery voltage sampling value is greater than the set threshold value, enter the second step detection step; otherwise, do not proceed to the next step, and stop the insulation impedance value detection;

[0019] Step 3.2, disconnect the relay contact switches K1 and K2, then continuously collect the battery positive electrode-PE voltage value three times, the values are Up1_t1, Up1_t2, Up1_t3 respectively; continuously collect the battery negative electrode-PE voltage value three times, the values are Un1_t1, Un1_t2, Un1_t3 respectively, and calculate the middle values Up1_m1 and Un1_m1 in the size order of the two groups of data values respectively;

[0020] Step 3.3, step 2 is repeated k times, respectively obtaining k intermediate values, respectively Up1_m1, Up1_m2,..., Up1_mk and Un1_m1, Un1_m2,..., Un1_mk, and calculating the average value of each group and ;

[0021] Step 3.4, closing the relay contact switches K1 and K2, and then continuously collecting the positive electrode pair PE voltage value three times, the values being Up2_t1, Up2_t2, Up2_t3; continuously collecting the negative electrode pair PE voltage value three times, the values being Un2_t1, Un2_t2, Un2_t3, and respectively calculating the values Up2_m1 and Un2_m1 in the size order of the two groups of data values

[0022] Step 3.5, step 4 is repeated k times, respectively obtaining k intermediate values, respectively Up2_m1, Up2_m2,..., Up2_mk and Un2_m1, Un2_m2,..., Un2_mk, and calculating the average value of each group and ;

[0023] Step 3.6, calculating the intermediate variable R123 = R1 + R2 + R3 = R4 + R5 + R6, R23 = R2 + R3 = R5 + R6

[0024] Step 3.7, according to the formula , the total equivalent impedance value of the positive electrode pair PE is calculated

[0025] Step 3.8, according to the formula , the total equivalent impedance value of the negative electrode pair PE is calculated

[0026] Step 3.9, according to the formula , the insulation impedance value of the positive electrode pair PE is calculated

[0027] Step 3.10, according to the formula , the insulation impedance value of the negative electrode pair PE is calculated

[0028] As a further technical scheme of the application: the direct current positive and negative electrode current processing module comprises a data filter, the input signal of the data filter being the positive electrode current original value Idc_S_P and the negative electrode current original value Idc_S_N, and the output signal being the processed positive electrode current signal filtered value Idc_Filter_P and the negative electrode current filtered value Idc_Filter_N.

[0029] As a further technical scheme of the application: the current value processing procedure steps are as follows:

[0030] I. The positive and negative electrode current original values Idc_S_P and Idc_S_N obtained by sampling are respectively passed through a digital low-pass filter to obtain filtered current values Idc_DF_P and Idc_DF_N;

[0031] II. The filtered current values of step 1 are obtained three times in succession, the positive electrode is Idc_DF_P1, Idc_DF_P2, Idc_DF_P3 respectively, and the negative electrode is Idc_DF_N1, Idc_DF_N2, Idc_DF_N3 respectively. The values Idc_P_M1 and Idc_N_M1 in the middle of the size sorting of the two groups of data values are calculated respectively;

[0032] III. Step II is repeated k times to obtain k intermediate values, which are Idc_P_M1, Idc_P_M2,..., Idc_P_Mk and Idc_N_M1, Idc_N_M2,..., Idc_N_Mk respectively, and the final filtering result of the direct current side current is calculated and .

[0033] The one or more technical solutions provided in the embodiments of the application have at least the following technical effects or advantages:

[0034] The insulation impedance detection circuit optimized by the application, in cooperation with the multiple software filtering methods, detects whether there is an insulation anomaly, and judges whether the abnormal point is located inside the converter according to the difference between the direct currents at the positive electrode inlet and the negative electrode outlet of the direct current side. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is an insulation impedance value detection circuit schematic diagram;

[0036] Figure 2 It is a direct current side current data processing method schematic diagram;

[0037] Figure 3 It is an insulation detection and abnormal position judgment method flow chart. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0039] The application provides an insulation detection and abnormal position judgment method suitable for energy storage converters, which comprises the following steps:

[0040] Step 1, after the energy storage converter AC-DC molded case circuit breaker is closed, the internal control system auxiliary power supply is powered off;

[0041] Step 2, detect the current working state of the energy storage converter, if the current is in a non-stop state or the battery voltage detection value is not greater than the set threshold, do not perform insulation detection related operations; if the current is in a stop state, and the battery voltage value is greater than the set threshold, then proceed to the next step, and perform insulation impedance value calculation;

[0042] Step 3, enter the insulation impedance value calculation module, calculate the insulation impedance value of the positive electrode of the battery to PE and the insulation impedance value of the negative electrode of the battery to PE;

[0043] Step 4, judge the size of the smaller value of the insulation impedance value of the positive and negative electrodes to PE and the impedance threshold. If the smaller impedance value of the two is not less than the impedance threshold, the insulation is normal, and directly return to step 2 for next detection; if the smaller impedance value of the two is less than the impedance threshold, then proceed to the next step;

[0044] Step 5, if the insulation alarm processing method set by the system is fault shutdown, the energy storage converter directly enters the fault state, and this method will no longer judge the position of the abnormal point; if the insulation alarm processing method set by the system is only alarm without shutdown, then proceed to the next step;

[0045] Step 6, detect whether the system is in a charging or discharging state, if not, continue to wait for power instructions in the current state; if yes, proceed to the next step;

[0046] Step 7, enter the DC positive and negative electrode current processing module, obtain the filtered positive and negative electrode current values Idc_Filter_P and Idc_Filter_N; calculate the difference value delta_Idc of the two;

[0047] Step 8, if delta_Idc is greater than the DC threshold, it is determined that the insulation impedance abnormal point is located inside the energy storage converter; otherwise, it is determined that the insulation impedance abnormal point is located outside the energy storage converter.

[0048] Figure 1The schematic diagram of the insulation impedance detection circuit designed in the method is shown in the figure. BAT+ and BAT- in the figure respectively represent the positive and negative poles of the battery; R1, R2, R3, R4, R5 and R6 in the figure are resistors, wherein R1=R4, R2=R5 and R3=R6; Rp and Rn respectively represent the total equivalent resistance of the positive and negative poles of the battery to the ground PE, wherein Rp is composed of the sampling circuit impedance value R_AD_P of the positive pole of the battery to the PE and the insulation impedance value Rpx of the positive pole of the battery to the PE, and Rn is composed of the sampling circuit impedance value R_AD_N of the negative pole of the battery to the PE and the insulation impedance value Rnx of the negative pole of the battery to the PE; Up and Un respectively represent the sampling voltage values of the positive and negative poles of the battery to the PE; K1 and K2 represent controllable relay contact switches.

[0049] The calculation method of the insulation impedance is as follows:

[0050] Step 3.1, in the shutdown state, if the battery voltage sampling value is greater than the set threshold value, the second step detection step is entered. Otherwise, the next step is not performed, and the insulation impedance value detection is stopped;

[0051] Step 3.2, the relay contact switches K1 and K2 are turned off, then the battery positive pole to PE voltage value is continuously collected three times, the values are Up1_t1, Up1_t2 and Up1_t3 respectively; the battery negative pole to PE voltage value is continuously collected three times, the values are Un1_t1, Un1_t2 and Un1_t3 respectively, and the middle values Up1_m1 and Un1_m1 in the size ordering of the two groups of data values are respectively calculated;

[0052] Step 3.3, step 2 is repeated k times, and k middle values are respectively obtained, which are Up1_m1, Up1_m2,..., Up1_mk and Un1_m1, Un1_m2,..., Un1_mk, and the average values of each group are calculated and ;

[0053] Step 3.4, the relay contact switches K1 and K2 are turned on, then the battery positive pole to PE voltage value is continuously collected three times, the values are Up2_t1, Up2_t2 and Up2_t3 respectively; the battery negative pole to PE voltage value is continuously collected three times, the values are Un2_t1, Un2_t2 and Un2_t3 respectively, and the middle values Up2_m1 and Un2_m1 in the size ordering of the two groups of data values are respectively calculated;

[0054] Step 3.5, step 4 is repeated k times, and k middle values are respectively obtained, which are Up2_m1, Up2_m2,..., Up2_mk and Un2_m1, Un2_m2,..., Un2_mk, and the average values of each group are calculated and ;

[0055] Step 3.6, calculate the intermediate variable R123 = R1 + R2 + R3 = R4 + R5 + R6, R23 = R2 + R3 = R5 + R6;

[0056] Step 3.7, according to the formula Calculate the total equivalent impedance value of the positive electrode of the battery to PE;

[0057] Step 3.8, according to the formula Calculate the total equivalent impedance value of the negative electrode of the battery to PE;

[0058] Step 3.9, according to the formula Calculate the insulation impedance value of the positive electrode of the battery to PE;

[0059] Step 3.10, according to the formula Calculate the insulation impedance value of the negative electrode of the battery to PE.

[0060] Inside the energy storage converter, a Hall current sensor is installed at the outer end of the DC load switch, respectively for detecting the DC current signal flowing through the positive electrode of the energy storage converter and the DC current signal flowing through the negative electrode of the energy storage converter. Figure 2 The figure is a schematic diagram of the DC side current data processing method. In the figure, Idc_S_P and Idc_S_N are the positive electrode current raw value and the negative electrode current raw value, respectively; Idc_Filter_P and Idc_Filter_N are the final data processing completed positive electrode current filtered value and negative electrode current filtered value, respectively.

[0061] The current value processing procedure is as follows:

[0062] Ⅰ, the positive and negative electrode current raw values Idc_S_P and Idc_S_N obtained by sampling are respectively passed through a digital low-pass filter to obtain the filtered current values Idc_DF_P and Idc_DF_N;

[0063] Ⅱ, continuously obtain three times the filtered current values of step 1, the positive electrode is Idc_DF_P1, Idc_DF_P2, Idc_DF_P3, and the negative electrode is Idc_DF_N1, Idc_DF_N2, Idc_DF_N3, respectively. Calculate the values Idc_P_M1 and Idc_N_M1 in the middle of the size sorting of the two groups of data values;

[0064] Ⅲ, repeat step II k times, respectively obtain k intermediate values, respectively Idc_P_M1, Idc_P_M2,..., Idc_P_Mk and Idc_N_M1, Idc_N_M2,..., Idc_N_Mk, and calculate the final filtered result of the DC side current and .

[0065] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

[0066] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and a person skilled in the art should consider the description as a whole, and the technical solutions in each embodiment have been properly combined to form other embodiments which are easily understood by a person skilled in the art.

Claims

1. A method for insulation detection and abnormal position determination of an energy storage converter, characterized by: The following steps are involved: Step 1: After the AC and DC molded case circuit breakers of the energy storage converter are closed, the auxiliary power supply of the internal control system is completed; Step 2: Detect the current working state of the energy storage converter. If it is not in the shutdown state or the battery voltage detection value is not greater than the set threshold, no insulation detection related operations are performed; if it is in the shutdown state and the battery voltage value is greater than the set threshold, proceed to the next step to calculate the insulation resistance value; Step 3: Enter the insulation resistance value calculation module to calculate the insulation resistance value of the battery positive electrode to PE and the insulation resistance value of the battery negative electrode to PE; Step 4: Determine the smaller of the insulation resistance values ​​of the positive and negative electrodes to PE and the impedance threshold. If the smaller of the two impedance values ​​is not less than the impedance threshold, then the insulation is normal and the process returns directly to step 2 for the next test. If the smaller of the two impedance values ​​is less than the impedance threshold, then the process proceeds to the next step. Step 5: If the insulation alarm processing method set by the system is fault shutdown, the energy storage converter will directly shut down and enter the fault state. This method will no longer determine the location of the abnormal point. If the insulation alarm processing method set by the system is only alarm without shutdown, proceed to the next step. Step 6: Check whether the system is in the charging or discharging state. If not, continue to wait for power instructions in the current state; if so, proceed to the next step; Step 7: Enter the DC positive and negative current processing module to obtain the filtered positive and negative current values ​​Idc_Filter_P and Idc_Filter_N; calculate the difference between the two, delta_Idc; Step 8: If delta_Idc is greater than the DC threshold, it is determined that the abnormal point of insulation impedance is located inside the energy storage converter; otherwise, it is determined that the abnormal point of insulation impedance is located outside the energy storage converter.

2. The insulation detection and abnormal position determination method for an energy storage converter according to claim 1, characterized in that: The insulation resistance value calculation module is implemented by an insulation resistance value detection circuit, which includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a relay contact switch K1 and a relay contact switch K2. One end of the resistor R1 is connected to the resistor R2 and the relay contact switch K1, and the other end of the resistor R2 is connected to the battery positive electrode BAT+. The other end of the resistor R1 is connected to the relay contact switch K1 and the resistor R3. The other end of the resistor R3 is connected to the PE sampling circuit and the resistor R6. One end of the resistor R4 is connected to the resistor R5 and the relay contact switch K2. The other end of the resistor R5 is connected to the battery positive electrode BAT-. The other end of the resistor R4 is connected to the relay contact switch K2 and the other end of the resistor R6.

3. The insulation detection and abnormal position determination method for an energy storage converter according to claim 2, characterized in that: The resistance value of the resistor R1 is the same as that of the resistor R4 , the resistance value of the resistor R2 is the same as that of the resistor R5 , and the resistance value of the resistor R3 is the same as that of the resistor R6 .

4. The insulation detection and abnormal position determination method for an energy storage converter according to claim 2, characterized in that: Inside the energy storage converter, at the outer end of the DC load switch, a Hall current sensor is installed on the positive and negative battery lines, respectively, to detect the DC current signal flowing through the positive and negative poles of the energy storage converter.

5. The insulation detection and abnormal position determination method for an energy storage converter according to claim 3, characterized in that: The calculation method of insulation resistance is as follows: Step 3.1: In the shutdown state, if the battery voltage sampling value is greater than the set threshold, the second step of detection is entered; otherwise, the next step is not performed and the insulation resistance value detection is stopped; Step 3.

2. Disconnect the relay contact switches K1 and K2, and then continuously collect the battery positive electrode to PE voltage value three times, the values ​​are Up1_t1, Up1_t2, Up1_t3 respectively; continuously collect the battery negative electrode to PE voltage value three times each, the values ​​are Un1_t1, Un1_t2, Un1_t3 respectively, and calculate the middle values ​​Up1_m1 and Un1_m1 of the two groups of data values ​​respectively; Repeat step 3.3 and step 2 k times to obtain k intermediate values, namely Up1_m1, Up1_m2, ..., Up1_mk and Un1_m1, Un1_m2, ..., Un1_mk, and calculate the average value of each group and ; Step 3.

4. Close relay contacts K1 and K2, and then continuously collect the voltage value of the battery positive electrode to PE three times, the values ​​are Up2_t1, Up2_t2, and Up2_t3 respectively; continuously collect the voltage value of the battery negative electrode to PE three times each, the values ​​are Un2_t1, Un2_t2, and Un2_t3 respectively, and calculate the values ​​Up2_m1 and Un2_m1 in the middle of the two groups of data values. Repeat steps 3.5 and 4 k times to obtain k intermediate values, namely Up2_m1, Up2_m2, ..., Up2_mk and Un2_m1, Un2_m2, ..., Un2_mk, and calculate the average value of each group. and ; Step 3.

6. Calculate the intermediate variables R123 = R1 + R2 + R3 = R4 + R5 + R6, R23 = R2 + R3 = R5 + R6; Step 3.7: According to the formula Calculate the total equivalent impedance value of the battery positive electrode to PE; Step 3.8: According to the formula Calculate the total equivalent impedance value of the battery negative electrode to PE; Step 3.9: According to the formula Calculate the insulation resistance of the battery positive electrode to PE; Step 3.10: According to the formula Calculate the insulation resistance of the battery negative electrode to PE; R_AD_P is the impedance value of the battery positive electrode to PE sampling circuit, and R_AD_N is the impedance value of the battery negative electrode to PE sampling circuit.

6. The insulation detection and abnormal position determination method for an energy storage converter according to claim 1, characterized in that: The DC positive and negative current processing module includes a data filter, the input signals of the data filter are the positive current original value Idc_S_P and the negative current original value Idc_S_N, and the output signals are the processed positive current signal filtered value Idc_Filter_P and the negative current filtered value Idc_Filter_N.

7. The insulation detection and abnormal position determination method for an energy storage converter according to claim 6, characterized in that: The current value processing steps are as follows: Ⅰ. The sampled positive and negative current raw values ​​Idc_S_P and Idc_S_N are respectively passed through digital low-pass filters to obtain filtered current values ​​Idc_DF_P and Idc_DF_N; Ⅱ. Obtain the current values ​​after filtering in step Ⅰ three times in a row. The positive poles are Idc_DF_P1, Idc_DF_P2, and Idc_DF_P3 respectively; the negative poles are Idc_DF_N1, Idc_DF_N2, and Idc_DF_N3 respectively. Calculate the middle values ​​of the two groups of data values, Idc_P_M1 and Idc_N_M1 respectively. Ⅲ. Repeat step Ⅱ k times to obtain k intermediate values, namely Idc_P_M1, Idc_P_M2, ..., Idc_P_Mk and Idc_N_M1, Idc_N_M2, ..., Idc_N_Mk, and calculate the final filtering result of the DC side current. and .

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