Capacitor durability test series control circuit

Abstract

A capacitor durability test series control circuit relates to the technical field of capacitor test. Comprising multiple paths of durability test control circuits which are arranged in sequence, each path of durability test control circuit is used for connecting two tested capacitors in pairs, and the two tested capacitors in pairs are connected in series reversely; the durability test control circuit comprises a capacitance test direct current power supply, a capacitance test alternating current power supply, a direct current monitoring unit and an alternating current and direct current control unit. The capacitance test direct current power supply is connected with a tested capacitor through the direct current monitoring unit and the alternating current and direct current control unit. The direct current monitoring unit is used for leakage current detection and discharge control of the two corresponding tested capacitors, and the alternating current and direct current control unit is used for controlling whether the two corresponding tested capacitors are connected or not to carry out a durability test. According to the utility model, open circuit and short circuit states of each pair of capacitors are monitored in the whole process, and fault capacitors are eliminated, so that the test can be continuously and effectively carried out.

Description

TECHNICAL FIELD

[0001] The utility model relates to capacitor test technical field, concretely is a kind of capacitor durability test series connection control circuit. BACKGROUND

[0002] Capacitor durability test refers to the environmental conditions and specified test time, to the capacitor for continuous electrical load and temperature effect, to assess its long-term stability and reliability of a test method.This test is carried out on capacitor test and evaluation, to determine whether it meets predetermined technical requirements and quality standards.

[0003] According to the Electronic Industries Association standard-EIA IS-749, the measured capacitor is connected in series in a defined manner, and the test method in the industry is to divide the capacitor into 11 pairs of capacitors, each pair is connected in reverse series by two capacitors, and the positive and negative ends of each capacitor are connected in parallel with the positive and negative ends of the DC power supply through inductance, AC voltage is applied to the head and tail of the 11 pairs of series capacitors, and then put into high-temperature oven for test.

[0004] The above test scheme has the following shortcomings: 1, test fixture needs to be full of 11 pairs of capacitors, otherwise manual short-circuiting is needed to achieve the closed-loop operation of the circuit;2, leakage current of each pair of capacitors cannot be monitored during test;3, short-circuit state of each pair of capacitors cannot be monitored during test;4, the whole test cannot continue when one capacitor is open during test;5, each pair of capacitors cannot be discharged individually after test. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a kind of capacitor durability test series connection control circuit, can effectively solve the problems in background art.

[0006] The technical scheme for realizing the above-mentioned purpose is: a kind of capacitor durability test series connection control circuit, characterized by: including the durability test control circuit of multiple ways in turn, each way durability test control circuit is used to connect two measured capacitors in pairs, two measured capacitors in pairs are connected in reverse series;

[0007] The durability test control circuit includes capacitor test DC power supply, capacitor test AC power supply, DC monitoring unit, AC / DC control unit, and capacitor test DC power supply is connected with measured capacitor through DC monitoring unit and AC / DC control unit respectively;

[0008] The AC / DC control unit includes on-off control switch and relay gating module, and the on-off control switch is used to control the relay gating module, and the on-off control switch is connected with the DC monitoring unit;

[0009] The two measured capacitors in reverse series of each durability test circuit are connected in reverse series in turn and connected at two ends of the capacitor test AC power supply, and the relay selection module of each durability test control circuit is connected in parallel at the positive electrode end of the corresponding two measured capacitors in reverse series.

[0010] The DC monitoring unit is used for leakage current detection and discharge control of the corresponding two measured capacitors, and the AC / DC control unit is used for controlling whether the corresponding two measured capacitors are connected for durability test.

[0011] Further, the DC monitoring unit comprises a 12V DC power supply, resistors R1, R2, R3, R4, R5, R6, R9, R10, a triode Q2, a relay J1, a thermistor RYM2, capacitors C1, C3, C4, diodes D4, D9, an inductor L2, and a voltage stabilizing tube D5.

[0012] One end of the resistors R5 and R9 is connected in parallel and serves as an output start 1 for inputting low or high level signals, the other end of the resistor R5 is connected to the positive electrode of the 12V DC power supply and the negative electrode of the diode D4, the positive electrode of the diode D4 is connected to the collector of the triode Q2, the emitter of the triode Q2 is connected to the negative electrode of the 12V DC power supply and one end of the resistor R10, and the other end of the resistor R10 is connected to the other end of the resistor R9 and the base of the triode Q2.

[0013] The coil of the relay J1 is connected in parallel at two ends of the diode D4, one end of the capacitor C1, the 4th pin and the 7th pin of the relay, and one end of the capacitor C4 are connected in parallel as a DC output 1 middle, the DC output 1 middle is connected to the negative electrode of the two measured capacitors, the other end of the capacitor C1 is connected to the 3rd pin and the 6th pin of the relay J1, the other end of the capacitor C4 is connected to the 5th pin and the 8th pin of the relay J1, the 4th pin and the 3rd pin and the 7th pin and the 6th pin of the relay J1 are respectively normally closed contacts, and the 4th pin and the 5th pin and the 7th pin and the 8th pin of the relay J1 are respectively normally open contacts.

[0014] One end of the resistor R1 is connected to the 3rd pin of the relay J1, and the other end is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the positive electrode of the capacitor test DC power supply.

[0015] One end of the thermistor RYM2 is connected to the 8th pin of the relay J1, and the other end is connected to one end of the inductor L2, the other end of the inductor L2 is connected to the negative electrode of the diode D9, one end of the resistor R6 and R3, and the positive electrode of the capacitor C3, the positive electrode of the diode D9, the other end of the resistor R6, and the negative electrode of the capacitor C3 are connected to the negative electrode of the capacitor test DC power supply, the other end of the resistor R3 is connected to one end of the resistor R4, the positive electrode of the voltage stabilizing tube D5 is connected to the negative electrode of the capacitor test DC power supply, and the negative electrode of the voltage stabilizing tube D5 is connected to the other end of the resistor R4 and serves as a leakage signal output.

[0016] Further, the relay selection module comprises a relay J2, a pressure sensitive resistor RYM1, a capacitor C2, inductors L1 and L3, and a switch control circuit comprising a triode Q3, a diode D8, resistors R11 and R12.

[0017] One end of the resistor R11 is connected to the anode of the diode D4 in the DC monitoring unit, and the other end is connected to one end of the resistor R12 and the base of the triode Q3, respectively.

[0018] One end of the capacitor C2 and the 4th pin and the 7th pin of the relay J2 are connected in parallel, and an AC interface AC1 is arranged, the other end of the capacitor C2 is connected to one end of the pressure sensitive resistor RYM1, the 5th pin and the 8th pin of the relay J2 are connected in parallel and are connected to the other end of the pressure sensitive resistor RYM1, and an AC interface AC2 is arranged, one end of the inductors L1 and L3 is connected to the positive pole of the capacitor test DC power supply, the other end of the inductor L1 is connected to the 5th pin of the relay J2, the other end of the inductor L3 is connected to the 7th pin of the relay J2, and the 4th pin and the 5th pin and the 7th pin and the 8th pin of the relay J2 are common open contacts.

[0019] Further, the relay selection module further comprises resistors R7 and R8, a capacitor C10, a photoelectric element U2, diodes D1, D2, D6, D7 and D10, a voltage stabilizing tube D3 and a 3.3V DC power supply.

[0020] The negative pole of the diode D1 and the positive pole of the diode D2 are connected to the AC interface AC2, the positive pole of the diode D1 is connected to the positive pole of the diode D6, the negative pole of the diode D2 is connected to the negative pole of the diode D7 and the negative pole of the voltage stabilizing tube D3, respectively, the negative pole of the diode D6 and the positive pole of the diode D7 are connected in parallel and are connected to the connection point between the capacitor C2 and the pressure sensitive resistor RYM1.

[0021] One end of the resistor R7 and the negative pole of the diode D10 are connected to the 1st pin of the input end of the photoelectric element U2, the other end of the resistor R7 is connected to the positive pole of the voltage stabilizing tube D3, the positive pole of the diode D6 and the positive pole of the diode D10 are connected and are connected to the 2nd pin of the input end of the photoelectric element U2, the 3rd pin of the output end of the photoelectric element U2 is connected to one end of the capacitor C10 and the negative pole of the 12V DC power supply, respectively, the other end of the capacitor C10 is connected to the 4th pin of the output end of the photoelectric element U2 and one end of the resistor R8, and serves as an open circuit signal output end, and the other end of the resistor R8 is connected to the positive pole of the 3.3V DC power supply.

[0022] The beneficial effects of the utility model are as follows:

[0023] The utility model discloses freely select the quantity of the measured capacitor, reduced manual operation makes the equipment more intelligent, overcome the technical defects of the prior art in the capacitor less than the capacitor of setting quantity, need manual short -circuit clamp to reach the closed loop work of circuit.

[0024] The utility model discloses whole process monitoring every pair of capacitor's open -circuit, short -circuit state, and rejecting the fault capacitor makes the test can continue effectively carries out.

[0025] The utility model discloses the leakage current of the measured capacitor is important to ensure system stability and product quality and reliability, the utility model can gather the leakage current state of every pair of measured capacitor in the whole process of test, provides more comprehensive data support for test result.

[0026] The utility model discloses the two measured capacitors of corresponding connection of every way durability test control circuit can be discharged separately, overcome the technical defects in the prior art, need after the test stops, discharge operation is carried out to all capacitors in series loop, and discharge time reduces 20% or more, provides the guarantee for personnel operation safety. DRAWINGS

[0027] Figure 1 It is the principle diagram of the utility model

[0028] Figure 2 It is the circuit diagram of durability test series control circuit of the utility model;

[0029] Figure 3 It is the circuit diagram of DC monitoring unit;

[0030] Figure 4 It is the circuit diagram of AC and DC control unit;

[0031] Figure 5 It is the measured capacitor series connection state schematic diagram;

[0032] Figure 6 It is the principle diagram of discharge circuit of the utility model;

[0033] Figure 7 It is the control principle diagram of the utility model working state. DETAILED DESCRIPTION

[0034] As Figures 1-5 The utility model discloses freely select the quantity of the measured capacitor, reduced manual operation makes the equipment more intelligent, overcome the technical defects of the prior art in the capacitor less than the setting quantity, need manual short -circuit clamp to reach the closed loop work of circuit.

[0035] The durability test control circuit comprises a capacitor test DC power supply 1, a capacitor test AC power supply 2, a DC monitoring unit 3, and an AC / DC control unit 4.

[0036] The DC monitoring unit 3 comprises a 12V DC power supply, resistors R1, R2, R3, R4, R5, R6, R9, R10, a transistor Q2, a relay J1, a thermistor RYM2, capacitors C1, C3, C4, a transistor Q2, diodes D4, D9, an inductor L2, and a voltage stabilizing tube D5.

[0037] One end of the resistors R5 and R9 is connected in parallel and serves as an output start 1 for inputting a low or high level signal, the other end of the resistor R5 is connected to the positive pole of the 12V DC power supply and the negative pole of the diode D4, the positive pole of the diode D4 is connected to the collector of the transistor Q2, the emitter of the transistor Q2 is connected to the negative pole of the 12V DC power supply and one end of the resistor R10, and the other end of the resistor R10 is connected to the other end of the resistor R9 and the base of the transistor Q2;

[0038] The coil of the relay J1 is connected in parallel across the diode D4, one end of the capacitor C1, the 4th and 7th pins of the relay, and one end of the capacitor C4 are connected in parallel as a DC output 1 middle, the DC output 1 middle is connected to the negative poles of the two measured capacitors, the other end of the capacitor C1 is connected to the 3rd and 6th pins of the relay J1, the other end of the capacitor C4 is connected to the 5th and 8th pins of the relay J1, the 4th and 3rd pins and the 7th and 6th pins of the relay J1 are normally closed contacts, and the 4th and 5th pins and the 7th and 8th pins of the relay J1 are normally open contacts;

[0039] One end of the resistor R1 is connected to the 3rd pin of the relay J1, and the other end is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the positive pole of the capacitor test DC power supply.

[0040] One end of the thermistor RYM2 is connected to the 8th pin of the relay J1, and the other end is connected to one end of the inductor L2, the other end of the inductor L2 is connected to the negative pole of the diode D9, one end of the resistors R6 and R3, and the positive pole of the capacitor C3, the positive pole of the diode D9, the other end of the resistor R6, and the negative pole of the capacitor C3 are connected to the negative pole of the capacitor test DC power supply (i.e. GND in Figure 2 The other end of the resistor R3 is connected to one end of the resistor R4, the positive pole of the voltage stabilizing tube D5 is connected to the negative pole of the capacitor test DC power supply, the negative pole of the voltage stabilizing tube D5 is connected to the other end of the resistor R4 and serves as a leakage signal output.

[0041] The AC / DC control unit 4 comprises a on-off control switch 4.1 and a relay gating module 4.2, the relay gating module 4.2 comprises a relay J2, a pressure sensitive resistor RYM1, inductors L1 and L3, a capacitor C2, resistors R7 and R8, a capacitor C10, a photo coupler U2, diodes D1, D2, D6, D7, D10, a voltage stabilizing tube D3, and a 3.3V DC power supply; the switch control circuit comprises a triode Q3, a diode D8, resistors R11 and R12.

[0042] One end of the resistor R11 is connected to the anode of the diode D4 in the DC monitoring unit, and the other end is connected to one end of the resistor R12 and the base of the triode Q3, respectively; the collector of the triode Q3 is connected to the anode of the diode D8; the cathode of the diode D8 is connected to the anode of the 12V DC power supply; the emitter of the triode Q3 is connected to the cathode of the 12V DC power supply and the other end of the resistor R12, respectively; the coil of the relay J2 is connected in parallel to the diode D8.

[0043] One end of the capacitor C2, the 4th pin and the 7th pin of the relay J2 are connected in parallel, and an AC interface AC1 is arranged; the other end of the capacitor C2 is connected to the pressure sensitive resistor RYM1; the 5th pin and the 8th pin of the relay J2 are connected in parallel, and the other end of the pressure sensitive resistor RYM1 is connected to the AC interface AC2; one end of the inductors L1 and L3 is connected to the anode of the capacitor test DC power supply, the other end of the inductor L1 is connected to the 5th pin of the relay J2, the other end of the inductor L3 is connected to the 7th pin of the relay J2, and the 4th pin and the 5th pin, and the 7th pin and the 8th pin of the relay J2 are common open contacts.

[0044] The cathode of the diode D1 and the anode of the diode D2 are connected to the AC interface AC2; the anode of the diode D1 is connected to the anode of the diode D6; the cathode of the diode D2 is connected to the cathode of the diode D7 and the cathode of the voltage stabilizing tube D3, respectively; the cathode of the diode D6 and the anode of the diode D7 are connected in parallel, and are connected to the connection point between the capacitor C2 and the pressure sensitive resistor RYM1.

[0045] The 1st pin of the input end of the photo coupler U2 is connected to one end of the resistor R7 and the cathode of the diode D10, respectively; the other end of the resistor R7 is connected to the anode of the voltage stabilizing tube D3; the anode of the diode D6 and the anode of the diode D10 are connected to the 2nd pin of the input end of the photo coupler U2; the 3rd pin of the output end of the photo coupler U2 is connected to one end of the capacitor C10 and the cathode of the 12V DC power supply, respectively; the other end of the capacitor C10 is connected to the 4th pin of the output end of the photo coupler U2 and one end of the resistor R8, and serves as an open circuit signal output end; the other end of the resistor R8 is connected to the anode of the 3.3V DC power supply.

[0046] The output end of the alternating current interface AC1 in the first durability test control circuit, the alternating current interface AC2 in the eleventh durability test control circuit and the output end of the capacitor test alternating current power supply 2 are connected, the alternating current interface AC2 in the first durability test control circuit is connected with the alternating current interface AC1 in the second durability test control circuit, the alternating current interface AC2 in the second durability test control circuit is connected with the alternating current interface AC1 in the third durability test control circuit, the alternating current interface AC2 in the third durability test control circuit is connected with the alternating current interface AC1 in the fourth durability test control circuit, the alternating current interface AC2 in the fourth durability test control circuit is connected with the alternating current interface AC1 in the fifth durability test control circuit, the alternating current interface AC2 in the fifth durability test control circuit is connected with the alternating current interface AC1 in the sixth durability test control circuit, the alternating current interface AC2 in the sixth durability test control circuit is connected with the alternating current interface AC1 in the seventh durability test control circuit, the alternating current interface AC2 in the seventh durability test control circuit is connected with the alternating current interface AC1 in the eighth durability test control circuit, the alternating current interface AC2 in the eighth durability test control circuit is connected with the alternating current interface AC1 in the ninth durability test control circuit, the alternating current interface AC2 in the ninth durability test control circuit is connected with the alternating current interface AC1 in the tenth durability test control circuit, and the alternating current interface AC2 in the tenth durability test control circuit is connected with the alternating current interface AC1 in the eleventh durability test control circuit.

[0047] The durability test of each circuit is connected in turn in reverse series to the two ends of the capacitor test alternating current power supply, and the relay selection module of each durability test control circuit is connected in parallel to the positive electrode end of the two measured capacitors in reverse series.

[0048] As shown in Figure 7 In the actual working process of the utility model, the leakage signal output and the open circuit signal output end of each durability test control circuit are connected with the input end of the single-chip microcomputer respectively, the output start 1 is connected with the output end of the single-chip microcomputer, and the specific working process is as follows:

[0049] When the number of test capacitors is exactly eleven pairs, the two test capacitors corresponding to the first durability test control circuit are C20 and C21, the two test capacitors corresponding to the second durability test control circuit are C22 and C23, the two test capacitors corresponding to the third durability test control circuit are C26 and C27, the two test capacitors corresponding to the fourth durability test control circuit are C28 and C29, the two test capacitors corresponding to the fifth durability test control circuit are C30 and C31, the two test capacitors corresponding to the sixth durability test control circuit are C34 and C35, the two test capacitors corresponding to the seventh durability test control circuit are C37 and C38, the two test capacitors corresponding to the eighth durability test control circuit are C41 and C42, the two test capacitors corresponding to the ninth durability test control circuit are C43 and C44, the two test capacitors corresponding to the tenth durability test control circuit are C45 and C46, and the two test capacitors corresponding to the eleventh durability test control circuit are C49 and C50.

[0050] The AC1 in the first durability test control circuit is an alternating current interface AC1. Figure 3 The AC1 in the first durability test control circuit is an alternating current interface AC1. Figure 3 The AC2 in the first durability test control circuit is an alternating current interface AC2.

[0051] When starting the test, the output start 1 of each durability test control circuit inputs a high-level signal, the triode Q2 is turned on, the size of the base current is limited by the resistor R10 to prevent excessive current from damaging the triode Q2, the relay J1 is attracted, the 4, 5 pins and the 7, 8 pins of the relay J1 are turned on (C4 plays a role in protecting the relay at this time), the direct current leakage current passes through the relay J1 to the thermistor RYM2 (protection when the test capacitor is short-circuited for a long time), then passes through the inductor L2 to isolate the alternating component, passes through the capacitor C3 for filtering, passes through the resistor R6 for leakage current sampling (leakage current signal 1), the resistors R3 and R4 play a current limiting role, and the voltage stabilizing tube D5 protects the leakage current signal 1 and outputs a leakage detection signal. The short-circuit detection of the test capacitor is actually to detect the size of the leakage current value to determine whether it is short-circuited.

[0052] At this time, the base input of the transistor Q3 of each durability test control circuit is low level, the transistor Q3 is not conducting, the relay J2 is not attracted, the AC power of the capacitor test is formed into a series loop through the AC interface AC1 in the first durability test control circuit, the measured capacitors C20, C21, C22, C23, C26, C27, C28, C29, C30, C31, C34, C35, C37, C38, C41, C42, C43, C44, C45, C46, C49, C50 and the AC interface AC2 in the eleventh durability test control circuit, and the positive pole of the capacitor test DC power supplies DC voltage to the measured capacitors through the inductors L1 and L3, so that the AC and DC superposition is realized on the measured capacitors, the inductors L1 and L3 are used to prevent the AC from entering the capacitor test DC power supply, and the varistor RYM1 protects the AC input.

[0053] The diodes D1, D2, D6 and D7 form a rectifier bridge, and the AC is formed into DC after passing through the rectifier bridge. When the circuit is not opened, the light coupling U2 is not conducting due to the blocking of the circuit by the voltage stabilizing tube D3, the open circuit signal output end outputs high level, and the relay enable module of the AC control unit is not started. When the circuit is opened, the voltage stabilizing tube D3 is conducting, the light coupling U2 is conducting, the open circuit signal output end outputs low level, the output start 1 of the corresponding circuit is given low level, and the relay enable module J2 of the AC control unit is closed. The circuit is short-circuited through the relay, and the current does not pass through the measured capacitors.

[0054] During the test, the leakage current is detected throughout the process. When the leakage current is greater than the determination value, the durability test control circuit of the circuit determines that it is short-circuited. The single-chip microcomputer controls the output start 1 of the circuit to change from high level to low level, the DC monitoring unit is switched to the discharge circuit, the transistor Q2 is not conducting, the relay J1 is not attracted, the positive pole of the corresponding measured capacitor is connected to the discharge resistor R1 and R2 through the normally closed end of the relay J1, and then to the positive pole of the measured capacitor, forming a discharge circuit, as shown in the specific Figure 6 The electricity on the measured capacitor starts to discharge through the circuit, the capacitor C1 protects the relay J1, the base input of the transistor Q3 is high level, the transistor Q3 is conducting, the relay J2 is attracted, and the measured capacitor is short-circuited.

[0055] Similarly, during the test, when the circuit is opened, the open circuit signal output end of the durability test control circuit outputs low level. At this time, the single-chip microcomputer controls the output start 1 of the corresponding durability test control circuit to be given low level, the relay enable module J2 of the AC control unit is closed, and the measured capacitor is short-circuited. The current does not pass through the measured capacitor of the durability test control circuit.

[0056] The above-mentioned example adopts eleven-way endurance test control circuit, when the actual test capacitor is less than eleven pairs, for example, only five pairs, the input high level signal of the first five-way endurance test control circuit can be controlled by the single-chip microcomputer; the input low level signal of the remaining six-way endurance test control circuit, the corresponding DC monitoring unit is switched to the discharge circuit, the triode Q2 is not conducted, the relay J1 is not attracted, the corresponding connected negative pole of the measured capacitor passes through the normally closed end of the relay J1 to the discharge resistance R1, R2 and then to the positive pole of the measured capacitor, forming a discharge circuit, the electricity on the measured capacitor starts to discharge through the circuit, and the capacitor C1 plays a role of protecting the relay J1.

[0057] The six-way endurance test control circuit not connected with the measured circuit inputs high level to the base of the triode Q3, the triode Q3 is conducted, and the relay J2 is attracted, so that the series capacitor loop of the measured capacitor is closed through the relay J2 in the AC-DC control unit.

[0058] When the test is finished, the output start 1 input low level, the triode Q2 is not conducted, the relay J1 is not attracted, the triode Q3 in the AC-DC control unit is conducted, the relay J2 is attracted, AC1 is connected with AC2 through the closed contact of the relay J2, the negative pole of the measured capacitor passes through the 4, 3 pins and 7, 6 pins of the relay J1 to the discharge resistance R1, R2 and then to the positive pole of the measured capacitor, forming a discharge circuit, so that the electricity on the measured capacitor starts to discharge through the circuit when the power supply is not working. The capacitor C1 plays a role of protecting the relay.

[0059] The number of the measured capacitors can be freely selected by the high and low level of the given output start signal, and the purpose of the series loop is achieved.

Claims

1. A capacitor endurance test series control circuit, characterized by: The durability test control circuit comprises a plurality of durability test control circuits arranged in sequence, each of which is used for connecting two measured capacitors in a pair, and the two measured capacitors in the pair are connected in reverse series; The durability test control circuit comprises a capacitor test DC power supply, a capacitor test AC power supply, a DC monitoring unit and an AC / DC control unit, and the capacitor test DC power supply is connected with the measured capacitors through the DC monitoring unit and the AC / DC control unit; The AC / DC control unit comprises an on-off control switch and a relay gating module, and the on-off control switch is used for controlling the relay gating module and is connected with the DC monitoring unit; The measured capacitors connected in reverse series in each durability test circuit are connected in reverse series in sequence at two ends of the capacitor test AC power supply, and the relay gating modules of the durability test control circuits are connected in parallel at positive poles of the two measured capacitors connected in reverse series. The DC monitoring unit is used for leakage current detection and discharge control of the two measured capacitors, and the AC / DC control unit is used for controlling whether the two measured capacitors are connected for durability test.

2. The series connection control circuit for a capacitor endurance test according to claim 1, characterized by: The DC monitoring unit comprises a 12V DC power supply, resistors R1, R2, R3, R4, R5, R6, R9, R10, a transistor Q2, a relay J1, a thermistor RYM2, capacitors C1, C3, C4, diodes D4, D9, an inductor L2 and a voltage stabilizing tube D5. One end of the resistors R5 and R9 is connected in parallel and serves as an output start 1 for inputting a low-level or high-level signal, the other end of the resistor R5 is connected with the positive pole of the 12V DC power supply and the negative pole of the diode D4, the positive pole of the diode D4 is connected with the collector of the transistor Q2, the emitter of the transistor Q2 is connected with the negative pole of the 12V DC power supply and one end of the resistor R10, and the other end of the resistor R10 is connected with the other end of the resistor R9 and the base of the transistor Q2. The coil of the relay J1 is connected in parallel at two ends of the diode D4, one end of the capacitor C1, the 4th pin and the 7th pin of the relay and one end of the capacitor C4 are connected in parallel as a DC output 1, the DC output 1 is connected with the negative poles of the two measured capacitors, the other end of the capacitor C1 is connected with the 3rd pin and the 6th pin of the relay J1, the other end of the capacitor C4 is connected with the 5th pin and the 8th pin of the relay J1, the 4th pin and the 3rd pin and the 7th pin and the 6th pin of the relay J1 are respectively normally closed contacts, and the 4th pin and the 5th pin and the 7th pin and the 8th pin of the relay J1 are respectively normally open contacts; One end of the resistor R1 is connected with the 3rd pin of the relay J1, and the other end of the resistor R1 is connected with one end of the resistor R2, and the other end of the resistor R2 is connected with the positive pole of the capacitor test DC power supply. One end of the thermistor RYM2 is connected to the 8th pin of the relay J1, and the other end is connected to one end of the inductor L2, the other end of the inductor L2 is connected to the negative electrode of the diode D9, one end of the resistors R6 and R3, and the positive electrode of the capacitor C3, the positive electrode of the diode D9, the other end of the resistor R6, and the negative electrode of the capacitor C3 are connected to the negative electrode of the capacitor test DC power supply, the other end of the resistor R3 is connected to one end of the resistor R4, the positive electrode of the voltage stabilizing tube D5 is connected to the negative electrode of the capacitor test DC power supply, the negative electrode of the voltage stabilizing tube D5 is connected to the other end of the resistor R4 and serves as a leakage signal output.

3. The series connection control circuit for a capacitor endurance test according to claim 1, wherein: The relay gating module includes a relay J2, a pressure-sensitive resistor RYM1, a capacitor C2, inductors L1 and L3, and a switch control circuit including a triode Q3, a diode D8, resistors R11 and R12. One end of the resistor R11 is connected to the positive electrode of the diode D4 in the DC monitoring unit, and the other end is connected to one end of the resistor R12 and the base of the triode Q3, the collector of the triode Q3 is connected to the positive electrode of the diode D8, the negative electrode of the diode D8 is connected to the positive electrode of the 12V DC power supply, the emitter of the triode Q3 is connected to the negative electrode of the 12V DC power supply and the other end of the resistor R12, and the coil of the relay J2 is connected in parallel across the diode D8. One end of the capacitor C2, the 4th pin and the 7th pin of the relay J2 are connected to each other and are provided with an AC interface AC1, the other end of the capacitor C2 is connected to one end of the pressure-sensitive resistor RYM1, the 5th pin and the 8th pin of the relay J2 are connected to each other and are connected to the other end of the pressure-sensitive resistor RYM1 and are provided with an AC interface AC2, one end of the inductors L1 and L3 is connected to the positive electrode of the capacitor test DC power supply, the other end of the inductor L1 is connected to the 5th pin of J2, the other end of the inductor L3 is connected to the 7th pin of J2, and the 4th pin and the 5th pin and the 7th pin and the 8th pin of the relay J2 are respectively normally open contacts.

4. A series capacitor durability test string control circuit according to claim 3, characterized in that: The relay gating module further includes resistors R7 and R8, a capacitor C10, a light couple U2, diodes D1, D2, D6, D7, D10, a voltage stabilizing tube D3, and a 3.3V DC power supply. The negative electrode of the diode D1 and the positive electrode of the diode D2 are connected to the AC interface AC2, the positive electrode of the diode D1 is connected to the positive electrode of the diode D6, the negative electrode of the diode D2 is connected to the negative electrode of the diode D7 and the negative electrode of the voltage stabilizing tube D3, the negative electrode of the diode D6 and the positive electrode of the diode D7 are connected to each other and are connected to the connection point between the capacitor C2 and the thermistor RYM1. One end of the resistor R7 and the negative electrode of the diode D10 are connected to the 1st pin of the input end of the light couple U2, the other end of the resistor R7 is connected to the positive electrode of the voltage stabilizing tube D3, the positive electrode of the diode D6 and the positive electrode of the diode D10 are connected to the 2nd pin of the input end of the light couple U2; the 3rd pin of the output end of the light couple U2 is connected to one end of the capacitor C10 and the negative electrode of the 12V DC power supply, the other end of the capacitor C10 is connected to the 4th pin of the output end of the light couple U2 and one end of the resistor R8 and serves as an open circuit signal output end, and the other end of the resistor R8 is connected to the positive electrode of the 3.3V DC power supply.

Images