Aging test circuit and system of capacitor

Abstract

The invention is suitable for the technical field of capacitors, and provides an aging test circuit and system for a capacitor, and the aging test circuit is internally provided with a charging and discharging switching unit, a voltage collection unit, a current control unit, a processing unit, a first test end and n second test ends. As the aging test can be simultaneously carried out on n capacitors to be tested at most, the aging test efficiency is improved. As the voltage acquisition unit can acquire the actual voltage at the two ends of each capacitor to be detected in the charging process in real time, the current control unit can acquire the actual current flowing through each capacitor to be detected in the charging process in real time, and the processing unit can detect a defective capacitor according to the actual voltage and the actual current. And the current control unit is controlled to cut off the charging loop of the defective capacitor, so that the safety of the aging test process is improved. The charging and discharging processes of the capacitor to be tested are completed through the charging and discharging switching unit, so that the circuit structure is simplified, and the testing cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of capacitors, and in particular, relates to an aging test circuit and system for capacitors. Background Art

[0002] The aging test process of aluminum electrolytic capacitors is an important part of the production process of aluminum electrolytic capacitors. It simulates the temperature, voltage or current stresses that aluminum electrolytic capacitors are subjected to during actual use by charging and discharging the manufactured aluminum electrolytic capacitors for the first time. It can not only repair the damaged oxide film dielectric on the surface of the aluminum electrolytic capacitors, but also screen out defective products. However, the existing capacitor aging test circuit has low safety, low test efficiency and high test cost. Summary of the invention

[0003] In view of this, an embodiment of the present application provides a capacitor aging test circuit and system to solve the technical problems of low safety, low test efficiency and high test cost of the existing capacitor aging test circuit.

[0004] In a first aspect, an embodiment of the present application provides an aging test circuit for a capacitor, comprising a charge and discharge switching unit, a voltage acquisition unit, a current control unit, a processing unit, a first test terminal, and n second test terminals, where n is an integer greater than 1;

[0005] The first test end is used to connect the positive electrode of each capacitor to be tested, each of the second test ends is used to connect a different negative electrode of the capacitor to be tested, and the first test end and all the second test ends are connected to the charge-discharge switching unit;

[0006] The charge-discharge switching unit is connected to the programmable voltage source and the host computer; the charge-discharge switching unit is used to charge each of the capacitors to be tested by the charging voltage provided by the programmable voltage source when receiving a charging control signal from the host computer, and control each of the capacitors to be tested to discharge when receiving a discharge control signal from the host computer;

[0007] The voltage acquisition unit is connected to the first test terminal, all the second test terminals and the processing unit; the voltage acquisition unit is used to collect the actual voltage across the two ends of each of the capacitors to be tested during the charging process, and send the actual voltage to the processing unit;

[0008] The current control unit is connected to the charge-discharge switching unit and the processing unit; the current control unit is used to collect the actual current flowing through each of the capacitors to be tested during the charging process, and send the actual current to the processing unit;

[0009] The processing unit is used to determine the problematic capacitor among the capacitors to be tested according to the actual voltage and the actual current, and control the current control unit to cut off the charging circuit of the problematic capacitor.

[0010] In an optional implementation of the first aspect, the charge-discharge switching unit includes a first control switch, a second control switch, and n bidirectional conductive units; the n bidirectional conductive units correspond one-to-one to the n second test terminals respectively;

[0011] The first conduction end of the first control switch is connected to the positive electrode of the programmable voltage source, the second conduction end of the first control switch and the first conduction end of the second control switch are connected to the first test end, the first end of each of the bidirectional conduction units is connected to the corresponding second test end, the second ends of all the bidirectional conduction units and the second conduction end of the second control switch are connected to the negative electrode of the programmable voltage source, the third end and the fourth end of each of the bidirectional conduction units are connected to the current control unit, and the controlled end of the first control switch and the controlled end of the second control switch are connected to the host computer;

[0012] The first control switch, the second control switch and each of the bidirectional conductive units are used to jointly control the on / off of the charging and discharging circuits of each of the capacitors to be tested.

[0013] In an optional implementation of the first aspect, the voltage acquisition unit has a positive voltage acquisition terminal, a positive voltage output terminal, n negative voltage acquisition terminals and n negative voltage output terminals, and the n negative voltage acquisition terminals and the n negative voltage output terminals are respectively in one-to-one correspondence with the n second test terminals; the positive voltage acquisition terminal of the voltage acquisition unit is connected to the first test terminal, each negative voltage acquisition terminal of the voltage acquisition unit is connected to the corresponding second test terminal, and the positive voltage output terminal of the voltage acquisition unit and all the negative voltage output terminals are connected to the processing unit;

[0014] The voltage collection unit includes a positive voltage collection unit and n negative voltage collection units, and the n negative voltage collection units correspond to the n negative voltage collection terminals and the n negative voltage output terminals respectively.

[0015] The input end of the positive electrode voltage acquisition unit serves as the positive electrode voltage acquisition end of the voltage acquisition unit, and the output end of the positive electrode voltage acquisition unit serves as the positive electrode voltage output end of the voltage acquisition unit; the positive electrode voltage acquisition unit is used to acquire the voltage of the positive electrode of each of the capacitors to be tested during the charging process, and send the voltage of the positive electrode to the processing unit;

[0016] The input end of each of the negative electrode voltage acquisition units serves as the negative electrode voltage acquisition end of the corresponding voltage acquisition unit, and the output end of each of the negative electrode voltage acquisition units serves as the negative electrode voltage output end of the corresponding voltage acquisition unit; the negative electrode voltage acquisition unit is used to collect the voltage of the negative electrode of the corresponding capacitor to be tested during the charging process, and send the voltage of the negative electrode to the processing unit.

[0017] In an optional implementation of the first aspect, the current control unit includes n current acquisition units and n constant current control units; the n current acquisition units and the n constant current control units correspond one-to-one to the n bidirectional conductive units respectively;

[0018] Each of the current acquisition units is connected to the fourth end of the corresponding bidirectional conduction unit and the first control end of the corresponding constant current control unit; the current acquisition unit is used to collect the actual current flowing through the corresponding capacitor to be tested during the charging process, and send the actual current to the processing unit through the corresponding constant current control unit;

[0019] The second control end of each constant current control unit is connected to the corresponding bidirectional conduction unit, and the controlled end of each constant current control unit is connected to the processing unit. The constant current control unit is used to adjust the charging current of the corresponding capacitor to be tested under the control of the processing unit.

[0020] In an optional implementation of the first aspect, the processing unit includes a channel selection unit, a digital signal processor, and a serial-to-parallel conversion unit;

[0021] The channel selection unit includes n first input terminals, n second input terminals and an output terminal; the n first input terminals are respectively connected to the n negative voltage output terminals of the voltage acquisition unit, the n second input terminals are respectively connected to the n output terminals of the current control unit, and the output terminal of the channel selection unit is connected to the first input terminal of the digital signal processor; the channel selection unit is used to obtain the voltage of the negative electrode of each of the capacitors to be tested during the charging process through the n first input terminals, obtain the actual current flowing through each of the capacitors to be tested during the charging process through the n second input terminals, and send the voltage of the negative electrode of each of the capacitors to be tested and the actual current flowing through each of the capacitors to be tested during the charging process to the digital signal processor in a multiple-choice manner;

[0022] The second input end of the digital signal processor is connected to the positive voltage output end of the voltage acquisition unit, and the output end of the digital signal processor is connected to the input end of the serial-to-parallel conversion unit; the digital signal processor is used to obtain the positive voltage of each of the capacitors to be tested during the charging process through the second input end, and determine the problematic capacitor among the capacitors to be tested according to the actual current flowing through each of the capacitors to be tested during the charging process and the positive voltage and negative voltage of each of the capacitors to be tested, and send a charging interruption instruction for the problematic capacitor to the serial-to-parallel conversion unit;

[0023] The n output ends of the serial-to-parallel conversion unit are all connected to the current control unit, and the n output ends correspond one-to-one to the n capacitors to be tested respectively; the serial-to-parallel conversion unit is used to output a charging interruption signal to the current control unit through the output end corresponding to the problematic capacitor, so that the current control unit cuts off the charging circuit of the problematic capacitor.

[0024] In an optional implementation of the first aspect, the positive voltage acquisition unit includes a first resistor and a second resistor; the first end of the first resistor serves as the positive voltage acquisition unit, the second end of the first resistor is connected to the first end of the second resistor and serves as the output end of the positive voltage acquisition unit, and the second end of the second resistor is grounded.

[0025] In an optional implementation of the first aspect, the negative electrode voltage acquisition unit includes a third resistor and a fourth resistor; the first end of the third resistor serves as the input end of the negative electrode voltage acquisition unit, the second end of the third resistor is connected to the first end of the fourth resistor and serves as the output end of the negative electrode voltage acquisition unit, and the second end of the fourth resistor is grounded.

[0026] In an optional implementation of the first aspect, the current acquisition unit includes a fifth resistor; the first end of the fifth resistor and the corresponding fourth end of the bidirectional conductive unit are connected to the ground, and the second end of the fifth resistor is connected to the corresponding constant current control unit.

[0027] In an optional implementation of the first aspect, the constant current control unit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an operational amplifier, a first capacitor, a second capacitor, a third control switch, and a fourth control switch;

[0028] The first end of the sixth resistor and the first conduction end of the third control switch are connected to the current collection DINAYA, the second conduction end of the third control switch is connected to the third end of the corresponding bidirectional conduction unit, the second end of the sixth resistor and the first end of the seventh resistor are connected to each other and serve as the output end of the constant current control unit, the second end of the seventh resistor and the first end of the first capacitor are connected to the negative input end of the operational amplifier, the second end of the first capacitor and the first end of the eighth resistor are connected to the output end of the operational amplifier, the second end of the eighth resistor, the first end of the second capacitor and the controlled end of the third control switch are connected to the first conduction end of the fourth control switch, the second end of the second capacitor and the second conduction end of the fourth control switch are connected to the ground, the controlled end of the fourth control switch serves as the controlled end of the constant current control unit, the first end of the ninth resistor serves as the reference voltage input end of the search constant current control unit, the reference voltage input end is connected to the processing unit, and the second end of the ninth resistor is connected to the positive input end of the operational amplifier.

[0029] In a second aspect, an embodiment of the present application provides an aging test system for a capacitor, comprising a host computer, a programmable voltage source, and m capacitor aging test circuits as described in any optional implementation of the first aspect above, where m is a positive integer.

[0030] The capacitor aging test circuit and system provided by the embodiments of the present application have the following beneficial effects:

[0031] The embodiment of the present application configures a charge-discharge switching unit, a voltage acquisition unit, a current control unit, a processing unit, a first test terminal and n second test terminals in each aging test circuit; since at most n capacitors to be tested can be connected between the first test terminal and the n second test terminals, the aging test circuit can perform aging tests on at most n capacitors to be tested at the same time, thereby improving the efficiency of the aging test of the capacitor. Since the voltage acquisition unit can collect the actual voltage at both ends of each capacitor to be tested during the charging process in real time, and the current control unit can collect the actual current flowing through each capacitor to be tested during the charging process in real time, the processing unit can detect the problem capacitor in the capacitor to be tested based on the above actual voltage and actual current, and control the current control unit to cut off the charging circuit of the problem capacitor in time, thereby improving the safety of the aging test process. Since the charging process and the discharging process of the capacitor to be tested are both completed by the charge-discharge switching unit, the same-station charging and discharging of the capacitor during the aging test is achieved, thereby simplifying the circuit structure of the aging test circuit and reducing the test cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 A schematic diagram of the structure of a capacitor aging test system provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of a capacitor aging test circuit provided in an embodiment of the present application;

[0035] Figure 3 A schematic structural diagram of a capacitor aging test circuit provided by another embodiment of the present application;

[0036] Figure 4 A schematic diagram of the circuit structure of a capacitor aging test circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] It should be noted that the terms used in the embodiments of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. In the description of the embodiments of the present application, unless otherwise specified, "multiple" refers to two or more than two, and "at least one", "one or more" refers to one, two or more. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, it is defined that the "first" and "second" features can explicitly or implicitly include one or more of the features.

[0038] References to "one embodiment" or "some embodiments" etc. described in this specification mean that a particular feature, structure or characteristic described in conjunction with the embodiment is included in one or more embodiments of the present application. Thus, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear at different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0039] The aging test process of aluminum electrolytic capacitors is an important part of the production and manufacturing process of aluminum electrolytic capacitors. It simulates the temperature, voltage or current stresses that aluminum electrolytic capacitors are subjected to during actual use by charging and discharging the manufactured aluminum electrolytic capacitors for the first time. It can not only repair the damaged oxide film medium on the surface of the aluminum electrolytic capacitors, but also screen out defective products.

[0040] Specifically, when charging an aluminum electrolytic capacitor for the first time, a relatively low voltage is usually used to slowly charge the aluminum electrolytic capacitor. During the charging process, as the amount of electricity stored in the aluminum electrolytic capacitor continues to increase, the voltage across the aluminum electrolytic capacitor will gradually increase to the maximum voltage it can withstand. In this process, tiny defects on the oxide film medium on the surface of the aluminum electrolytic capacitor will re-form a more solid oxide film under the action of the electric field, thereby repairing the oxide film medium. However, if there are serious defects on the oxide film medium, then during the charging process, the anode aluminum foil of the capacitor and the electrolyte will be connected through the serious defects, thereby instantly short-circuiting the capacitor. In this way, the voltage across the capacitor will instantly drop to the initial voltage, causing internal flash fires or even explosions in the capacitor, creating safety hazards.

[0041] In view of this, in order to improve the safety of the capacitor aging test process, improve the efficiency of the capacitor aging test, and reduce the cost of the capacitor aging test, the embodiment of the present application provides a capacitor aging test circuit and system. Figure 1 This is a schematic diagram of the structure of a capacitor aging test system provided in an embodiment of the present application. The aging test system can be used to perform aging tests on aluminum electrolytic capacitors or other capacitors with similar structures to aluminum electrolytic capacitors. Figure 1 As shown, the aging test system may include a host computer 10, a programmable voltage source 20, and m aging test circuits 30. m is a positive integer, and the specific value of m can be set according to actual needs, and the embodiment of the present application does not specifically limit it.

[0042] Among them, a communication connection is established between the host computer 10 and the programmable voltage source 20, and between the host computer 10 and all the aging test circuits 30. The communication connection can be a wireless communication connection or a wired communication connection. Exemplarily, the wireless communication connection may include a wireless fidelity (WIFI) connection or a Bluetooth connection, etc. The wired communication connection may include a serial communication connection (for example, a connection based on a serial communication interface such as RS-485 or RS-422) or a parallel communication connection, etc. The embodiment of the present application does not specifically limit the above-mentioned communication connection mode.

[0043] In practical applications, the host computer 10 may be an intelligent terminal device (e.g., a mobile phone or a computer), a server, a programmable logic controller (PLC) or a microcontroller (e.g., a single-chip microcomputer), etc. The specific type of the host computer 10 is not particularly limited in the present embodiment.

[0044] The aging test circuit 30 is used to perform an aging test on a capacitor to be tested (e.g., an aluminum electrolytic capacitor). Each aging test circuit 30 can perform an aging test on at most n capacitors to be tested at the same time. n is an integer greater than 1, and the specific value of n can be set according to actual needs, for example, n can be 64.

[0045] The programmable voltage source 20 is used to provide a preset charging voltage for each aging test circuit 30 , and the magnitude of the preset charging voltage can be controlled by the host computer 10 .

[0046] The host computer 10 is used to control the charging and discharging timing of each aging test circuit 30 .

[0047] Specifically, when it is necessary to charge the capacitor to be tested, the host computer 10 can send a charging control signal to the aging test circuit 30. After receiving the charging control signal, the aging test circuit 30 can charge each capacitor to be tested based on the preset charging voltage of the programmable voltage source 20. In addition, the aging test circuit 30 can also collect the actual voltage across each capacitor to be tested and the actual current flowing through each capacitor to be tested during the charging process, and detect whether there are any problem capacitors with unqualified quality in the capacitors to be tested based on the above actual voltage and actual current, and when it is detected that there are problem capacitors in the capacitors to be tested, cut off the charging circuit of the problem capacitor to stop charging the problem capacitor.

[0048] After charging is completed, when the capacitor to be tested needs to be discharged, the host computer 10 can send a discharge control signal to the aging test circuit 30. After receiving the discharge control signal, the aging test circuit 30 can control each capacitor to be tested to discharge, thereby restoring the voltage across the capacitor to be tested to the initial state before charging for subsequent use.

[0049] In addition, after the capacitor to be tested completes the aging test, the host computer 10 can obtain the aging test information of each capacitor to be tested from each aging test circuit 30 (for example, the actual current across each capacitor to be tested during the charging process, the actual current flowing through each capacitor to be tested during the charging process, or the identification information of the problem capacitor, etc.), so as to facilitate the tester to monitor the aging test process, or to facilitate the tester to eliminate the problem capacitor from the capacitor to be tested.

[0050] It can be seen from the above that the embodiment of the present application configures a host computer, a programmable voltage source and m aging test circuits in the aging test system of the capacitor, and the host computer controls the charging and discharging timing of each aging test circuit and the charging voltage provided by the programmable voltage source, so as to realize the intelligent control of the aging test process of the capacitor. Since each aging test circuit can perform aging tests on up to n capacitors to be tested at the same time, the entire aging test system can perform aging tests on up to m×n capacitors to be tested at the same time, thereby improving the aging test efficiency of the capacitor. Since the aging test circuit can monitor the actual voltage at both ends of each capacitor to be tested and the actual current flowing through each capacitor to be tested in real time during the charging process, and can detect the presence of a problem capacitor in the capacitor to be tested based on the above actual voltage and actual current, the charging circuit of the problem capacitor can be cut off in time, thereby reducing safety hazards and improving the safety of the aging test process. In addition, since the aging test circuit can not only charge each capacitor to be tested, but also directly discharge each capacitor to be tested after charging is completed, that is, the charging process and the discharging process involved in the aging test process of the capacitor are completed based on the same circuit, thus simplifying the circuit structure of the aging test circuit and reducing the aging test cost of the capacitor.

[0051] The structure and working principle of the aging test circuit provided in the embodiment of the present application are described below.

[0052] Figure 2 This is a schematic diagram of the structure of an aging test circuit provided in an embodiment of the present application. Figure 2 As shown, the aging test circuit 30 may include a charge and discharge switching unit 301, a voltage acquisition unit 302, a current control unit 303, a processing unit 304, a data transmission unit 305, a first test terminal A and n second test terminals B1-Bn.

[0053] The first test terminal A can be used to connect the positive electrode of each capacitor to be tested, and each second test terminal can be used to connect the negative electrode of a different capacitor to be tested. For example, the first second test terminal B1 can be used to connect the negative electrode of the first capacitor to be tested Cx1, the second second test terminal B2 can be used to connect the negative electrode of the second capacitor to be tested Cx2, and so on, the nth second test terminal Bn can be used to connect the negative electrode of the nth capacitor to be tested Cxn.

[0054] The charge-discharge switching unit 301 is connected to the programmable voltage source 20 and the host computer 10. Specifically, the positive power supply terminal of the charge-discharge switching unit 301 is connected to the positive electrode of the programmable voltage source 20, the negative power supply terminal of the charge-discharge switching unit 301 is connected to the negative electrode of the programmable voltage source 20, and the controlled end of the charge-discharge switching unit 301 is connected to the host computer 10. Optionally, the charge-discharge switching unit 301 can be used to connect the first test terminal A to the positive electrode of the programmable voltage source 20 and connect each second test terminal B1~Bn to the negative electrode of the programmable voltage source 20 when receiving a charging control signal from the host computer 10, so as to charge each capacitor Cx1~Cxn to be tested by the preset charging voltage provided by the programmable voltage source 20. Optionally, the charge and discharge switching unit 301 can also be used to disconnect the connection between the first test terminal A and the positive electrode of the programmable voltage source 20 when receiving a discharge control signal from the host computer 10, and connect the first test terminal A to the negative electrode of the programmable voltage source 20 to discharge each capacitor Cx1~Cxn to be tested.

[0055] The voltage acquisition unit 302 is connected to the first test terminal A, all the second test terminals B1-Bn and the processing unit 304. The voltage acquisition unit 302 can be used to collect the actual voltage across each capacitor Cx1-Cxn to be tested during the charging process, and send the actual voltage across each capacitor Cx1-Cxn to be tested during the charging process to the processing unit 304.

[0056] The current control unit 303 is connected to the charge-discharge switching unit 301 and the processing unit 304. The current control unit 303 can be used to collect the actual current flowing through each capacitor to be tested Cx1~Cxn during the charging process, and send the actual current flowing through each capacitor to be tested Cx1~Cxn during the charging process to the processing unit 304. The current control unit 303 can also be used to adjust the charging current of each capacitor to be tested Cx1~Cxn under the control of the processing unit 304.

[0057] The processing unit 304 is connected to the data transmission unit 305. The processing unit 304 can be used to detect whether there is a problem capacitor in the capacitors Cx1 to Cxn to be tested according to the actual voltage across each of the capacitors Cx1 to Cxn to be tested and the actual current flowing through each of the capacitors Cx1 to Cxn to be tested during the charging process, and when it is detected that there is a problem capacitor in the capacitors Cx1 to Cxn to be tested, control the current control unit 303 to adjust the charging current of the problem capacitor to 0, that is, cut off the charging circuit of the problem capacitor, thereby stopping charging the problem capacitor.

[0058] In addition, the processing unit 304 can also be used to send the aging test information of each capacitor Cx1 to Cxn to be tested or the identification information of the problematic capacitor to the host computer 10 through the data transmission unit 305 when receiving the problematic capacitor information acquisition instruction from the host computer 10.

[0059] It is understandable that, in practical applications, the aging test circuit 30 may further include a power supply unit (not shown in the figure). The power supply unit may be used to supply power to each unit in the aging test circuit 30 to ensure that each unit in the aging test circuit 30 can work normally.

[0060] It can be seen from the above that the embodiment of the present application configures a charge-discharge switching unit, a voltage acquisition unit, a current control unit, a processing unit, a first test terminal and n second test terminals in each aging test circuit; since at most n capacitors to be tested can be connected between the first test terminal and the n second test terminals, the aging test circuit can perform aging tests on at most n capacitors to be tested at the same time, thereby improving the aging test efficiency of the capacitor. Since the voltage acquisition unit can collect the actual voltage at both ends of each capacitor to be tested during the charging process in real time, and the current control unit can collect the actual current flowing through each capacitor to be tested during the charging process in real time, the processing unit can detect the problem capacitor in the capacitor to be tested according to the above actual voltage and actual current, and control the current control unit to cut off the charging circuit of the problem capacitor in time, thereby improving the safety of the aging test process. Since the charging process and the discharging process of the capacitor to be tested are both completed by the charge-discharge switching unit, the same-station charging and discharging of the capacitor during the aging test is realized, thereby simplifying the circuit structure of the aging test circuit and reducing the test cost.

[0061] Figure 3 This is a schematic diagram of the structure of an aging test circuit provided by another embodiment of the present application. Figure 3 As shown, in an optional embodiment, the charge-discharge switching unit 301 may include a first control switch 3011, a second control switch 3012 and n bidirectional conductive units 3013, and the n bidirectional conductive units correspond one-to-one to the n second test terminals B1-Bn respectively.

[0062] Among them, the first conduction end of the first control switch 3011 serves as the positive power supply end of the charge and discharge switching unit 301, the second conduction end of the first control switch 3011 and the first conduction end of the second control switch 3012 are commonly connected to the first test end A, the first end of each bidirectional conduction unit 3013 is connected to the corresponding second test end Bn, the second ends of all bidirectional conduction units 3013 are commonly connected to the second conduction end of the second control switch 3012 and serve as the negative power supply end of the charge and discharge switching unit 301, the third end and the fourth end of each bidirectional conduction unit 3013 are connected to the current control unit 303, and the controlled end of the first control switch 3011 and the controlled end of the second control switch 3012 are both connected to the host computer 20 (not shown in the figure).

[0063] The first control switch 3011 , the second control switch 3012 and each bidirectional conductive unit 3013 can be used to jointly control the on-off of the charging and discharging circuits of each capacitor Cx1 ˜Cxn to be tested.

[0064] Specifically, when it is necessary to charge each capacitor Cx1 to Cxn to be tested, the host computer 10 may send a charging control signal to the charge-discharge switching unit 301. The charging control signal may include a first on-signal for controlling the first control switch 3011 to be turned on and a first off-signal for controlling the second control switch 3012 to be turned off. The first control switch 3011 may be turned on upon receiving the first on-signal to connect the first test terminal A to the positive electrode of the programmable voltage source 20. The second control switch 3012 may be turned off upon receiving the first off-signal to disconnect the connection between the first test terminal A and the negative electrode of the programmable voltage source 20. The bidirectional conducting unit 3013 may connect the charging circuit of the corresponding capacitor to be tested when the first control switch 3011 is turned on and the second control switch 3012 is turned off, so that the programmable voltage source 20 charges each capacitor Cx1 to Cxn to be tested based on a preset charging voltage.

[0065] When it is necessary to discharge each capacitor Cx1 to Cxn to be tested, the host computer 10 may send a discharge control signal to the charge-discharge switching unit 301. The discharge control signal may include a second turn-off signal for controlling the first control switch 3011 to be turned off and a second turn-on signal for controlling the second control switch 3012 to be turned on. The first control switch 3011 may be turned off upon receiving the second turn-off signal to disconnect the connection between the first test terminal A and the positive electrode of the programmable voltage source 20. The second control switch 3012 may be turned on upon receiving the second turn-on signal to connect the first test terminal A to the negative electrode of the programmable voltage source 20. The bidirectional conduction unit 3013 may connect the discharge circuit of the corresponding capacitor to be tested when the first control switch 3011 is turned off and the second control switch 3012 is turned on, thereby discharging each capacitor Cx1 to Cxn to be tested.

[0066] like Figure 3 As shown, in an optional embodiment, the voltage acquisition unit 302 may have a positive voltage acquisition terminal, a positive voltage output terminal, n negative voltage acquisition terminals and n negative voltage output terminals, the n negative voltage acquisition terminals correspond one-to-one to the n second test terminals B1-Bn, and the n negative voltage output terminals correspond one-to-one to the n negative voltage acquisition terminals. The positive voltage acquisition terminal of the voltage acquisition unit 302 is connected to the first test terminal A, each negative voltage acquisition terminal of the voltage acquisition unit 302 is connected to the corresponding second test terminal, and the positive voltage output terminal and all negative voltage output terminals of the voltage acquisition unit 302 are connected to the processing unit 304.

[0067] The voltage acquisition unit 302 may include a positive voltage acquisition unit 3021 and n negative voltage acquisition units 3022 , and the n negative voltage acquisition units 3022 correspond to the n negative voltage acquisition terminals and the n negative voltage output terminals, respectively.

[0068] Specifically, the input end of the positive voltage acquisition unit 3021 serves as the positive voltage acquisition end of the voltage acquisition unit 301, and the output end of the positive voltage acquisition unit 3021 serves as the positive voltage output end of the voltage acquisition unit 301. The positive voltage acquisition unit 3021 can be used to acquire the voltages of the positive electrodes of the n capacitors Cx1 to Cxn to be tested during the charging process, and send the voltages of the positive electrodes of the n capacitors Cx1 to Cxn to be tested during the charging process to the processing unit 304.

[0069] The input end of each negative electrode voltage acquisition unit 3022 can be used as the negative electrode voltage acquisition end of the corresponding voltage acquisition unit 301, and the output end of each negative electrode voltage acquisition unit 3022 can be used as the negative electrode voltage output end of the corresponding voltage acquisition unit 301. The negative electrode voltage acquisition unit 3022 can be used to collect the voltage of the negative electrode of the corresponding capacitor to be tested during the charging process, and send the voltage of the negative electrode of the corresponding capacitor to be tested during the charging process to the processing unit 304.

[0070] like Figure 3 As shown, in an optional embodiment, the current control unit 303 may include n current acquisition units 3031 and n constant current control units 3032 , and the n current acquisition units 3031 and the n constant current control units 3032 correspond one-to-one to the n bidirectional conductive units 3013 , respectively.

[0071] Each current acquisition unit 3031 is connected to the fourth terminal of the corresponding bidirectional conduction unit 3013 and the first control terminal of the corresponding constant current control unit 3032. The current acquisition unit 3031 is used to collect the actual current flowing through the corresponding capacitor to be tested during the charging process, and send the actual current flowing through the corresponding capacitor to be tested during the charging process to the processing unit 304 through the corresponding constant current control unit 3032.

[0072] The second control end of each constant current control unit 3032 is connected to the third end of the corresponding bidirectional conduction unit 3013, and the output end and the controlled end of each constant current control unit 3032 are connected to the processing unit 304. The constant current control unit 3032 is used to output the actual current flowing through the corresponding capacitor to be tested during the charging process to the processing unit 304 through the output end. The constant current control unit 3032 is also used to adjust the charging current of the corresponding capacitor to be tested under the control of the processing unit 304.

[0073] like Figure 3 As shown, in an optional embodiment, the processing unit 304 may include a channel selection unit 3041 , a digital signal processor 3042 , and a serial-to-parallel conversion unit 3043 .

[0074] The channel selection unit 3041 includes n first input terminals, n second input terminals and an output terminal. Among them, the n first input terminals of the channel selection unit 3041 are respectively connected to the n negative voltage output terminals of the voltage acquisition unit 302, the n second input terminals of the channel selection unit 3041 are respectively connected to the output terminals of the n constant current control units 3032, and the output terminal of the channel selection unit 3041 is connected to the first input terminal of the digital signal processor 3042. The channel selection unit 3041 can obtain the voltage of the negative electrode of each capacitor to be tested Cx1~Cxn during the charging process through the n first input terminals, and can obtain the actual current flowing through each capacitor to be tested Cx1~Cxn during the charging process through the n second input terminals, and can send the voltage of the negative electrode of each capacitor to be tested Cx1~Cxn during the charging process and the actual current flowing through each capacitor to be tested Cx1~Cxn to the digital signal processor 3042 in a multiple-choice manner.

[0075] The second input terminal of the digital signal processor 3042 is connected to the output terminal of the positive voltage acquisition unit 3021, and the output terminal of the digital signal processor 3042 is connected to the input terminal of the serial-to-parallel conversion unit 3043. The digital signal processor 3042 can obtain the voltage of the positive electrode of each capacitor to be tested Cx1~Cxn during the charging process through its second input terminal. In addition, the digital signal processor 3042 can also determine the problem capacitor among the capacitors to be tested Cx1~Cxn according to the actual current flowing through each capacitor to be tested Cx1~Cxn during the charging process and the voltage of the positive electrode and the voltage of the negative electrode of each capacitor to be tested Cx1~Cxn, and send a charging interruption instruction for the problem capacitor to the serial-to-parallel conversion unit 3043. The charging interruption instruction is used to instruct the current control unit 303 to cut off the charging circuit of the problem capacitor.

[0076] The serial-to-parallel conversion unit 3043 may include n output terminals, and the n output terminals correspond one-to-one to the n constant current control units 3032. Specifically, each output terminal of the serial-to-parallel conversion unit 3043 may be connected to a controlled terminal of a corresponding constant current control unit 3032. When receiving a charging interruption instruction for a problem capacitor, the serial-to-parallel conversion unit 3043 may output a corresponding charging interruption signal to the corresponding constant current control unit 3032 through the output terminal corresponding to the problem capacitor, so that the corresponding constant current control unit 3032 adjusts the charging current of the problem capacitor to 0, thereby cutting off the charging circuit of the problem capacitor and stopping charging the problem capacitor.

[0077] Figure 4 The circuit structure diagram of a capacitor aging test circuit provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, in a specific embodiment, the first control switch 3011 and the second control switch 3012 can be semiconductor switches or other types of switches. The embodiment of the present application does not limit the specific types of the first control switch 3011 and the second control switch 3012. Exemplarily, the semiconductor switch may include a triode, a transistor or a thyristor. Among them, the transistor may include a metal-oxide-semiconductor field effect transistor (metal-oxide-semiconductor field effect transistor, MOSFET) or an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), etc.

[0078] Exemplarily, taking the first control switch 3011 as a first NMOS tube (i.e., N-type MOSFET) Q1, the drain of the first NMOS tube Q1 is the first conduction end of the first control switch 3011, the source of the first NMOS tube Q1 is the second conduction end of the first control switch 3011, and the gate of the first NMOS tube Q1 is the controlled end of the first control switch 3011.

[0079] Exemplarily, taking the second control switch 3012 as the second NMOS tube Q2 as an example, the drain of the second NMOS tube Q2 is the first conduction end of the second control switch 3012, the source of the second NMOS tube Q2 is the second conduction end of the second control switch 3012, and the gate of the second NMOS tube Q2 is the controlled end of the second control switch 3012.

[0080] When the first control switch 3011 is a first NMOS transistor and the second control switch 3012 is a second NMOS transistor Q2, the first on-signal in the charging control signal may be a high level signal, and the first off-signal may be a low level signal. The second off-signal in the discharging control signal may be a low level signal, and the second on-signal may be a high level signal.

[0081] like Figure 4 As shown, in a specific embodiment, the bidirectional conductive unit 3013 may be a bridge structure. For example, the bidirectional conductive unit 3013 may include a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. Among them, the cathode of the first diode D1 and the anode of the third diode D3 are connected together and serve as the first end of the bidirectional conductive unit 3013, the cathode of the second diode D2 and the anode of the fourth diode D4 are connected together and serve as the second end of the bidirectional conductive unit 3013, the cathode of the third diode D3 and the cathode of the fourth diode D4 are connected together and serve as the third end of the bidirectional conductive unit 3013, and the anode of the first diode D1 and the anode of the second diode D2 are connected together and serve as the fourth end of the bidirectional conductive unit 3013.

[0082] like Figure 4 As shown, in a specific embodiment, the positive voltage acquisition unit 3021 may include a first resistor R2 and a second resistor R2. The first end of the first resistor R1 may be used as the input end of the positive voltage acquisition unit 3021, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and serves as the output end of the positive voltage acquisition unit 3021, and the second end of the second resistor R2 is grounded.

[0083] like Figure 4As shown, in a specific embodiment, each negative voltage acquisition unit 3022 may include a third resistor R3 and a fourth resistor R4. The first end of the third resistor R3 serves as the input end of the negative voltage acquisition unit 3022, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and serves as the output end of the negative voltage acquisition unit 3022, and the second end of the fourth resistor R4 is grounded.

[0084] like Figure 4 As shown, in a specific embodiment, each current acquisition unit 3031 may include a fifth resistor R5. A first end of the fifth resistor R5 and a fourth end of the corresponding bidirectional conductive unit 3013 are grounded, and a second end of the fifth resistor R5 is connected to the corresponding constant current control unit 3032.

[0085] Each constant current control unit 3032 may include a sixth resistor R6 , a seventh resistor R7 , an eighth resistor R8 , a ninth resistor R9 , an operational amplifier UA1 , a first capacitor C1 , a second capacitor C2 , a third control switch 30321 , and a fourth control switch 30322 .

[0086] The first end of the sixth resistor R6 is connected to the first conduction end of the third control switch 30321 and serves as the first control end of the constant current control unit 3032. The second conduction end of the third control switch 30321 serves as the second control end of the constant current control unit 3032. The second end of the sixth resistor R6 is connected to the first end of the seventh resistor R7 and serves as the output end of the constant current control unit 3032. The second end of the seventh resistor R7 and the first end of the first capacitor C1 are connected to the negative input end of the operational amplifier UA1. The second end of the first capacitor C1 and the first end of the eighth resistor R8 are connected to the output end of the operational amplifier UA1. The second end of the ninth resistor R9 is connected to the positive input terminal of the operational amplifier UA1.

[0087] The seventh resistor R7, the first capacitor C1, the eighth resistor R8, the third control switch 30321, the second capacitor C2, the operational amplifier UA1 and the ninth resistor R9 constitute a cross-current control circuit.

[0088] Specifically, the positive input terminal of the operational amplifier UA1 can be used as a reference voltage input terminal for receiving the reference voltage Vref from the digital signal processor 3042. Different voltage differences between the positive input terminal and the negative input terminal of the operational amplifier UA1 will cause the operational amplifier UA1 to output different level signals. For example, when the reference voltage Vref at the positive input terminal of the operational amplifier UA1 is greater than the voltage at the negative input terminal, the operational amplifier UA1 outputs a high level signal; when the reference voltage Vref at the positive input terminal of the operational amplifier UA1 is less than the voltage at the negative input terminal, the operational amplifier UA1 outputs a low level signal. The level signal output by the operational amplifier UA1 is applied to the controlled end of the third control switch 30321 after low-pass filtering by the eighth resistor R8 and the second capacitor C2. Based on this, the amplitude of the level signal output by the operational amplifier UA1 can be adjusted by adjusting the size of the reference voltage Vref, thereby adjusting the conduction degree of the third control switch 30321. By adjusting the conduction degree of the third control switch 30321, the charging current of the capacitor to be tested can be adjusted, so that not only the constant current charging of each capacitor to be tested can be achieved, but also the charging current of the problematic capacitor can be adjusted to 0 when necessary to cut off the charging circuit of the problematic capacitor. The reference voltage Vref can be set according to actual needs, and the embodiment of the present application does not specifically limit it.

[0089] In practical applications, the third control switch 30321 and the fourth control switch 30322 can both be semiconductor switches or switches of other types. The embodiment of the present application does not limit the specific types of the third control switch 30321 and the fourth control switch 30322.

[0090] Exemplarily, taking the third control switch 30321 as the third NMOS tube Q3 as an example, the source of the third NMOS tube Q3 is the first conduction end of the third control switch 30321, the drain of the third NMOS tube Q3 is the second conduction end of the third control switch 30321, and the gate of the third NMOS tube Q3 is the controlled end of the third control switch 30321.

[0091] Exemplarily, taking the fourth control switch 30322 as the fourth NMOS tube Q4 as an example, the drain of the fourth NMOS tube Q4 is the first conduction end of the fourth control switch 30322, the source of the fourth NMOS tube Q4 is the second conduction end of the fourth control switch 30322, and the gate of the fourth NMOS tube Q4 is the controlled end of the fourth control switch 30322.

[0092] When the third control switch 30321 is the third NMOS transistor Q3 and the fourth control switch 30322 is the fourth NMOS transistor Q4, the charging interruption signal may be a high level signal.

[0093] The working principle of the capacitor aging test system provided in the embodiment of the present application is described below.

[0094] like Figures 1 to 4 As shown, when an aging test is required for the capacitor to be tested, the positive electrode of each capacitor to be tested can be connected to the first test terminal A of the aging test circuit 30, and the negative electrode of each capacitor to be tested can be connected to a second test terminal of the aging test circuit 30.

[0095] Before starting the aging test on the capacitor to be tested, a preset charging voltage and a preset charging current of the capacitor to be tested during the aging test may be set in the host computer 10 .

[0096] When the aging test of the capacitor to be tested begins, the host computer 10 can control the programmable voltage source 20 to output a power supply signal with a voltage of a preset charging voltage to each aging test circuit 30. In addition, the host computer 10 can send a charging control signal to each aging test circuit 30 to control the first control switch 3011 to be turned on and the second control switch 3012 to be turned off. When the first control switch 3011 is turned on and the second control switch 3012 is turned off, the positive electrode of each capacitor to be tested Cx1~Cxn is connected to the positive electrode of the programmable voltage source 30, and the negative electrode of each capacitor to be tested is connected to the negative electrode of the programmable voltage source 30 after passing through the first end of the bidirectional conductive unit 3013, the third end of the bidirectional conductive unit 3013, the third control switch 30321, the fifth resistor R5, the fourth end of the bidirectional conductive unit 3013 and the second end of the bidirectional conductive unit 3013, so that the programmable voltage source 30 charges each capacitor to be tested Cx1~Cxn.

[0097] During the charging process, the voltage of the positive electrode of the capacitors to be tested Cx1-Cxn is sent to the digital signal processor 3042 after being divided by the first resistor R1 and the second resistor R2; the voltage of the negative electrode of the capacitors to be tested Cx1-Cxn is sent to the channel selection unit 3041 after being divided by the third resistor R3 and the fourth resistor R4; the actual current flowing through the capacitor to be tested will produce a voltage drop on the fifth resistor R5, which is sent to the channel selection unit 3041 after being divided by the sixth resistor R6 and the seventh resistor R7 on the one hand, and sent to the negative input terminal of the operational amplifier UA1 after passing through the sixth resistor R6 and the seventh resistor R7 on the other hand. The channel selection unit 3041 can adopt a multiple-selection method to sequentially transmit the received voltage of the negative electrode of each capacitor to be tested Cx1-Cxn during the charging process and the actual current flowing through each capacitor to be tested Cx1-Cxn to the digital signal processor 3042. The digital signal processor 3042 can calculate the actual voltage across each of the capacitors Cx1 to Cxn to be tested during the charging process based on the voltage of the positive electrode and the voltage of the negative electrode of each of the capacitors Cx1 to Cxn to be tested during the charging process, and detect whether there is a problematic capacitor among the capacitors Cx1 to Cxn to be tested according to the actual voltage across each of the capacitors Cx1 to Cxn to be tested during the charging process and the actual current flowing through each of the capacitors Cx1 to Cxn to be tested. For example, when the actual voltage across a capacitor to be tested slowly rises to a certain voltage value and then suddenly drops to the initial value during the charging process, it means that the capacitor to be tested may be momentarily short-circuited, that is, the capacitor to be tested is a problematic capacitor.

[0098] In order to improve the safety of the capacitor aging test process, when the digital signal processor 3043 detects a problematic capacitor, it can send a charging interruption instruction for the problematic capacitor to the serial-to-parallel conversion unit 3043. The serial-to-parallel conversion unit 3043 can output a charging interruption signal (such as a high-level signal) through the corresponding output terminal to control the fourth control switch 30322 to turn off, thereby connecting the controlled end of the third control switch 30321 to the ground to turn off the third control switch 30321, thereby cutting off the charging circuit of the problematic capacitor and stopping charging the problematic capacitor.

[0099] After charging is completed, when it is necessary to discharge each capacitor Cx1 to Cxn to be tested, the host computer 10 can send a discharge control signal to each aging test circuit 30 to control the first control switch 3011 to be turned off and the second control switch 3012 to be turned on. When the first control switch 3011 is turned off and the second control switch 3012 is turned on, the connection between the positive electrode of each capacitor Cx1 to Cxn to be tested and the positive electrode of the programmable voltage source 30 is disconnected, and the positive electrode of each capacitor Cx1 to Cxn to be tested is connected to the negative electrode of each capacitor Cx1 to Cxn to be tested after passing through the second end of the bidirectional conduction unit 3013, the third end of the bidirectional conduction unit 3013, the third control switch 30321, the fifth resistor R5, the fourth end of the bidirectional conduction unit 3013 and the first end of the bidirectional conduction unit 3013, thereby discharging each capacitor Cx1 to Cxn to be tested.

[0100] After the aging test is completed, when the tester wants to eliminate the problematic capacitors from the capacitors Cx1 to Cxn to be tested, the host computer 10 can obtain the identification information of the problematic capacitors from the aging test circuit 30, so that the problematic capacitors can be accurately and efficiently eliminated.

[0101] It can be seen from the above that the capacitor aging test circuit provided in the embodiment of the present application can perform aging tests on multiple capacitors to be tested in batches, thereby improving the efficiency of the capacitor aging test. In addition, since the charging circuit of the problematic capacitor can be disconnected in time when the problematic capacitor is detected, the safety of the aging test can be improved. Since the charging and discharging of the capacitor during the aging test are achieved through the same circuit, the circuit structure is simple and the test cost is low.

[0102] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units is used as an example for illustration. In practical applications, the above-mentioned functions can be assigned to different functional units as needed, that is, the structure of the aging test circuit is divided into different functional units to complete all or part of the functions described above. The functional units included in the aging test circuit can be integrated on a circuit board. In addition, the specific names of the functional units are only for the convenience of distinguishing each other and are not used to limit the scope of protection of this application.

[0103] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0104] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A capacitor aging test circuit, characterized in that: It includes a charge-discharge switching unit, a voltage acquisition unit, a current control unit, a processing unit, a first test terminal and n second test terminals, where n is an integer greater than 1; The first test end is used to connect the positive electrode of each capacitor to be tested, each of the second test ends is used to connect a different negative electrode of the capacitor to be tested, and the first test end and all the second test ends are connected to the charge-discharge switching unit; The charge-discharge switching unit is connected to the programmable voltage source and the host computer; the charge-discharge switching unit is used to charge each of the capacitors to be tested by the charging voltage provided by the programmable voltage source when receiving a charging control signal from the host computer, and control each of the capacitors to be tested to discharge when receiving a discharge control signal from the host computer; The voltage acquisition unit is connected to the first test terminal, all the second test terminals and the processing unit; the voltage acquisition unit is used to collect the actual voltage across the two ends of each of the capacitors to be tested during the charging process, and send the actual voltage to the processing unit; The current control unit is connected to the charge-discharge switching unit and the processing unit; The current control unit is used to collect the actual current flowing through each of the capacitors to be tested during the charging process, and send the actual current to the processing unit; The processing unit is used to determine the problematic capacitor among the capacitors to be tested according to the actual voltage and the actual current, and control the current control unit to cut off the charging circuit of the problematic capacitor.

2. The capacitor aging test circuit according to claim 1, characterized in that: The charge-discharge switching unit includes a first control switch, a second control switch, and n bidirectional conductive units; the n bidirectional conductive units correspond to the n second test terminals one by one respectively; The first conduction end of the first control switch is connected to the positive electrode of the programmable voltage source, the second conduction end of the first control switch and the first conduction end of the second control switch are connected to the first test end, the first end of each of the bidirectional conduction units is connected to the corresponding second test end, the second ends of all the bidirectional conduction units and the second conduction end of the second control switch are connected to the negative electrode of the programmable voltage source, the third end and the fourth end of each of the bidirectional conduction units are connected to the current control unit, and the controlled end of the first control switch and the controlled end of the second control switch are connected to the host computer; The first control switch, the second control switch and each of the bidirectional conductive units are used to jointly control the on / off of the charging and discharging circuits of each of the capacitors to be tested.

3. The capacitor aging test circuit according to claim 1, characterized in that: The voltage acquisition unit has a positive voltage acquisition terminal, a positive voltage output terminal, n negative voltage acquisition terminals and n negative voltage output terminals, and the n negative voltage acquisition terminals and the n negative voltage output terminals are respectively in one-to-one correspondence with the n second test terminals; the positive voltage acquisition terminal of the voltage acquisition unit is connected to the first test terminal, each negative voltage acquisition terminal of the voltage acquisition unit is connected to the corresponding second test terminal, and the positive voltage output terminal of the voltage acquisition unit and all the negative voltage output terminals are connected to the processing unit; The voltage collection unit includes a positive voltage collection unit and n negative voltage collection units, and the n negative voltage collection units correspond to the n negative voltage collection terminals and the n negative voltage output terminals respectively. The input end of the positive electrode voltage acquisition unit serves as the positive electrode voltage acquisition end of the voltage acquisition unit, and the output end of the positive electrode voltage acquisition unit serves as the positive electrode voltage output end of the voltage acquisition unit; the positive electrode voltage acquisition unit is used to acquire the voltage of the positive electrode of each of the capacitors to be tested during the charging process, and send the voltage of the positive electrode to the processing unit; The input end of each of the negative electrode voltage acquisition units serves as the negative electrode voltage acquisition end of the corresponding voltage acquisition unit, and the output end of each of the negative electrode voltage acquisition units serves as the negative electrode voltage output end of the corresponding voltage acquisition unit; the negative electrode voltage acquisition unit is used to collect the voltage of the negative electrode of the corresponding capacitor to be tested during the charging process, and send the voltage of the negative electrode to the processing unit.

4. The capacitor aging test circuit according to claim 2, characterized in that: The current control unit comprises n current collection units and n constant current control units; the n current collection units and the n constant current control units correspond one-to-one to the n bidirectional conductive units respectively; Each of the current acquisition units is connected to the fourth end of the corresponding bidirectional conduction unit and the first control end of the corresponding constant current control unit; the current acquisition unit is used to collect the actual current flowing through the corresponding capacitor to be tested during the charging process, and send the actual current to the processing unit through the corresponding constant current control unit; The second control end of each constant current control unit is connected to the corresponding bidirectional conduction unit, and the controlled end of each constant current control unit is connected to the processing unit. The constant current control unit is used to adjust the charging current of the corresponding capacitor to be tested under the control of the processing unit.

5. The capacitor aging test circuit according to any one of claims 1 to 4, characterized in that: The processing unit includes a channel selection unit, a digital signal processor and a serial-to-parallel conversion unit; The channel selection unit includes n first input terminals, n second input terminals and an output terminal; the n first input terminals are respectively connected to the n negative voltage output terminals of the voltage acquisition unit, the n second input terminals are respectively connected to the n output terminals of the current control unit, and the output terminal of the channel selection unit is connected to the first input terminal of the digital signal processor; The channel selection unit is used to obtain the voltage of the negative electrode of each of the capacitors to be tested during the charging process through the n first input terminals, obtain the actual current flowing through each of the capacitors to be tested during the charging process through the n second input terminals, and send the voltage of the negative electrode of each of the capacitors to be tested and the actual current flowing through each of the capacitors to be tested during the charging process to the digital signal processor in a multiple-selection manner; The second input terminal of the digital signal processor is connected to the positive voltage output terminal of the voltage acquisition unit, and the output terminal of the digital signal processor is connected to the input terminal of the serial-to-parallel conversion unit; The digital signal processor is used to obtain the voltage of the positive electrode of each of the capacitors to be tested during the charging process through the second input terminal, and determine the problematic capacitor among the capacitors to be tested according to the actual current flowing through each of the capacitors to be tested during the charging process and the voltage of the positive electrode and the voltage of the negative electrode of each of the capacitors to be tested, and send a charging interruption instruction for the problematic capacitor to the serial-to-parallel conversion unit; The n output ends of the serial-to-parallel conversion unit are all connected to the current control unit, and the n output ends correspond one-to-one to the n capacitors to be tested respectively; the serial-to-parallel conversion unit is used to output a charging interruption signal to the current control unit through the output end corresponding to the problematic capacitor, so that the current control unit cuts off the charging circuit of the problematic capacitor.

6. The capacitor aging test circuit according to claim 3, characterized in that: The positive voltage acquisition unit includes a first resistor and a second resistor; the first end of the first resistor serves as the positive voltage acquisition unit, the second end of the first resistor is connected to the first end of the second resistor and serves as the output end of the positive voltage acquisition unit, and the second end of the second resistor is grounded.

7. The capacitor aging test circuit according to claim 3, characterized in that: The negative voltage acquisition unit includes a third resistor and a fourth resistor; the first end of the third resistor serves as the input end of the negative voltage acquisition unit, the second end of the third resistor is connected to the first end of the fourth resistor and serves as the output end of the negative voltage acquisition unit, and the second end of the fourth resistor is grounded.

8. The capacitor aging test circuit according to claim 4, characterized in that: The current collection unit includes a fifth resistor; a first end of the fifth resistor and a fourth end of the corresponding bidirectional conductive unit are connected to the ground, and a second end of the fifth resistor is connected to the corresponding constant current control unit.

9. The capacitor aging test circuit according to claim 4, characterized in that: The constant current control unit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, an operational amplifier, a first capacitor, a second capacitor, a third control switch and a fourth control switch; The first end of the sixth resistor and the first conduction end of the third control switch are connected to the current collection DINAYA, the second conduction end of the third control switch is connected to the third end of the corresponding bidirectional conduction unit, the second end of the sixth resistor and the first end of the seventh resistor are connected to each other and serve as the output end of the constant current control unit, the second end of the seventh resistor and the first end of the first capacitor are connected to the negative input end of the operational amplifier, the second end of the first capacitor and the first end of the eighth resistor are connected to the output end of the operational amplifier, the second end of the eighth resistor, the first end of the second capacitor and the controlled end of the third control switch are connected to the first conduction end of the fourth control switch, the second end of the second capacitor and the second conduction end of the fourth control switch are connected to the ground, the controlled end of the fourth control switch serves as the controlled end of the constant current control unit, the first end of the ninth resistor serves as the reference voltage input end of the search constant current control unit, the reference voltage input end is connected to the processing unit, and the second end of the ninth resistor is connected to the positive input end of the operational amplifier.

10. A capacitor aging test system, characterized in that: The invention comprises a host computer, a programmable voltage source and m capacitor aging test circuits as described in any one of claims 1 to 9, wherein m is a positive integer.

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