Novel capacitor durability test circuit

Abstract

The utility model discloses a novel capacitor durability test circuit, which comprises an alternating current output unit, a direct current output unit, a plurality of current transformers, a plurality of leakage current detection units and a plurality of tested capacitor banks, a single tested capacitor bank comprises two tested capacitors, and the cathodes of the two tested capacitors are connected. The three terminals are connected in series in opposite directions to form a three-terminal device, the alternating current output unit is provided with two alternating current output terminals, and the direct current output unit is provided with two direct current output terminals. According to the utility model, only one direct-current power supply and one alternating-current power supply are provided, or only one alternating-current and direct-current all-in-one machine is needed, and the alternating-current power supply is separated into multiple paths to be output through the current transmission and isolation effects of the current transformer, which is equivalent to providing a plurality of alternating-current power supplies; and the primary series connection mode of the current transformers is adopted, so that the current flowing through the current transformers is the same, thereby ensuring that the ripple current on each group of tested capacitors is consistent, achieving the effect of current sharing, and further ensuring the accuracy of the test result.

Description

Technical Field

[0001] The utility model relates to the technical field of capacitor testing, in particular to a novel capacitor durability testing circuit. Background Art

[0002] Two conductors close to each other, with a non-conductive insulating medium in between, form a capacitor. When voltage is applied between the two plates of the capacitor, the capacitor will store charge. Capacitors play an important role in tuning, bypassing, coupling, filtering and other circuits. With the rapid development of electronic information technology, the replacement speed of digital electronic products is getting faster and faster. The production and sales of consumer electronic products, mainly flat-screen TVs (LCD and PDP), laptops, digital cameras, etc., continue to grow, driving the growth of the capacitor industry.

[0003] High temperature load test is an important part of routine test and identification test of capacitors. It tests the tolerance of capacitors under the combined effect of environmental stress and electrical stress, and is also called durability or working life test. The existing test method requires providing an AC power supply for each pair of test capacitors (11 pairs of capacitors require 11 AC power supplies) to generate ripple current. Since the output parameters of each AC power supply have certain differences, the ripple current input to each pair of capacitors is inconsistent, and the test results will have certain deviations. The above problems need to be solved urgently. For this reason, a new capacitor durability test circuit is proposed. Utility Model Content

[0004] The technical problem to be solved by the utility model is: how to solve the problem that the existing test method requires providing an AC power supply for each pair of test capacitors to generate ripple current. Since the output parameters of each AC power supply themselves have certain differences, the ripple current input to each pair of capacitors is inconsistent, and the test results will have certain deviations. A new capacitor durability test circuit is provided.

[0005] The utility model solves the above technical problems through the following technical solutions. The utility model includes an AC output unit, a DC output unit, a plurality of current transformers, a plurality of leakage current detection units, and a plurality of capacitor groups to be measured. A single capacitor group to be measured includes two capacitors to be measured, and the negative electrodes of the two capacitors to be measured are connected, that is, they are connected in reverse series to form a three-terminal device. The AC output unit is provided with two AC output terminals, and the DC output unit is provided with two DC output terminals, which are respectively a positive terminal and a negative terminal. The primary side of the current transformer is provided with two primary terminals, which are sequentially connected in series and are respectively connected to the two AC output terminals after being connected in series. The secondary side is provided with two secondary terminals and a common terminal. The common terminal of each current transformer is connected to the positive terminal of the DC output unit. The negative electrode of each capacitor group to be measured is connected to the negative terminal of the DC output unit through a leakage current detection unit. The two positive electrodes of each capacitor group to be measured are respectively connected to the two secondary terminals of each current transformer. The leakage current of the capacitor to be measured is detected in real time through the leakage current detection unit. The models and specifications of each current transformer are the same.

[0006] Furthermore, the AC output unit is an AC power supply, and the DC output unit is a DC power supply.

[0007] Furthermore, the capacitor high temperature load test circuit also includes a plurality of DC-through and AC-through inductors, one end of which is connected to the leakage current detection unit, and the other end of which is directly connected to the negative terminal of the DC output unit.

[0008] Furthermore, the leakage current detection unit is a leakage current detection resistor, one end of the leakage current detection resistor is connected to the negative electrode of the capacitor group under test, and the other end is connected to the DC-isolating AC-isolating inductor.

[0009] Furthermore, the numbers of current transformers, leakage current detection resistors, capacitor banks to be measured, and DC-passing and AC-isolating inductors are all the same.

[0010] Furthermore, the AC output unit and the DC output unit are realized by an AC / DC integrated power supply.

[0011] Compared with the prior art, the utility model has the following advantages: the utility model only needs to provide one DC power supply and one AC power supply, or only needs one AC / DC integrated machine, and through the current transmission and isolation function of the current transformer, the AC power supply is separated into multiple outputs, which is equivalent to providing multiple AC power supplies; and the primary series connection mode of the current transformer is adopted to make the current flowing through the current transformer the same, thereby ensuring that the ripple current on each group of capacitors tested is consistent, achieving the effect of current balancing, and thus ensuring the accuracy of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the first embodiment of the utility model;

[0013] Figure 2 This is a schematic diagram of the overall structure of the third embodiment of the present utility model;

[0014] Figure 3 It is a schematic diagram of the overall structure of the fourth embodiment of the present utility model. DETAILED DESCRIPTION

[0015] The following is a detailed description of an embodiment of the utility model. This embodiment is implemented on the premise of the technical solution of the utility model, and a detailed implementation method and a specific operation process are given, but the protection scope of the utility model is not limited to the following embodiment.

[0016] Embodiment 1

[0017] like Figure 1 As shown, this embodiment provides a technical solution: a novel capacitor durability test circuit, including an AC output unit, a DC output unit, a plurality of current transformers 13, a plurality of leakage current detection units, and a plurality of capacitor groups 16 to be tested, wherein a single capacitor group 16 to be tested includes two capacitors to be tested, and the negative electrodes of the two capacitors to be tested are connected, that is, they are reversely connected in series to form a three-terminal device, the AC output unit is provided with two AC output terminals 11 (AC1 and AC2 respectively), the DC output unit is provided with two DC output terminals 12, which are respectively a positive terminal and a negative terminal, and the current transformer 1 The primary side of 3 is provided with two primary terminals, which are connected in series in sequence and are respectively connected to the two AC output terminals 11 after being connected in series. The secondary side is provided with two secondary terminals and a common terminal. The common terminal of each current transformer 13 is connected to the positive terminal of the DC output unit. The negative electrode of each measured capacitor group 16 is connected to the negative terminal of the DC output unit through a leakage current detection unit. The two positive electrodes of each measured capacitor group 16 are respectively connected to the two secondary terminals of each current transformer 13, and the leakage current of the measured capacitor is detected in real time through the leakage current detection unit.

[0018] In this embodiment, the AC output unit is an AC power supply, and the DC output unit is a DC power supply.

[0019] In this embodiment, the capacitor high temperature load test circuit further includes a plurality of DC-isolating AC-isolating inductors 14, one end of each of which is connected to the leakage current detection unit, and the other end of each of which is directly connected to the negative terminal of the DC output unit.

[0020] In this embodiment, the leakage current detection unit is a leakage current detection resistor 15 , one end of the leakage current detection resistor 15 is connected to the negative electrode of the capacitor group 16 to be measured, and the other end is connected to the DC-isolating AC-isolating inductor 14 .

[0021] In this embodiment, the two primary terminals of the primary side of the current transformer 13 are terminal 1 and terminal 2 respectively; the two secondary terminals and one common terminal of the secondary side are terminal 3, terminal 4, and terminal 5 respectively, wherein the common terminal is terminal 4.

[0022] In this embodiment, the primary series connection mode of the current transformer 13 is used to isolate and separate a ripple power supply into multiple small ripple power supplies, and provide ripple current to each capacitor group under test, thereby ensuring that the ripple current flowing through each capacitor group under test is consistent.

[0023] In this embodiment, the number of the current transformer 13, the leakage current detection resistor 15, the capacitor group 16 to be measured, and the DC-isolating AC-isolating inductor 14 are all the same, namely, 11.

[0024] In this embodiment, it should be noted that the same-named terminals of the current transformer 13 are only for convenience of representation, and the actual same-named terminals are determined by the actual circuit.

[0025] Working principle: the DC bias voltage is input through the common terminal 4 of the secondary of the current transformer 13, and is applied to the capacitor under test through the terminals 3 and 4 of the current transformer 13, the DC-to-AC inductor 14 and the leakage current detection resistor 15. The AC current is isolated by the current transformer 13 and applied to the capacitor under test through the terminals 3 and 5 of the current transformer 13; the primary terminals of multiple current transformers 13 are connected in series, so that the primary current flowing through each current transformer 13 is equal. Since the parameters of each current transformer 13 are consistent, the secondary current in each current transformer 13 is also equal, and finally the AC current flowing through the capacitor under test is also equal, thereby achieving the purpose of intelligent current sharing.

[0026] Embodiment 2

[0027] In this embodiment, the AC output unit and the DC output unit are implemented by an AC / DC integrated power supply.

[0028] Except for the above implementation, the other implementations in this embodiment are the same as those in the first embodiment.

[0029] Embodiment 3

[0030] like Figure 2As shown, in this embodiment, the common terminal of each current transformer 13 is connected to the positive terminal of the DC output unit through a leakage current detection unit, and the negative electrode of each measured capacitor group 16 is directly connected to the negative terminal of the DC output unit.

[0031] In this embodiment, the capacitor high temperature load test circuit further includes a plurality of direct current isolation inductors 14 , one end of each of which is connected to the leakage current detection unit, and the other end of each of which is connected to the common terminal of the current transformer 13 .

[0032] In this embodiment, the leakage current detection unit is a leakage current detection resistor 15 , one end of the leakage current detection resistor 15 is connected to the positive terminal of the DC output unit, and the other end is connected to the DC-isolating AC-isolating inductor 14 .

[0033] Except for the above implementation, the other implementations in this embodiment are the same as those in the first embodiment.

[0034] Embodiment 4

[0035] like Figure 3 As shown, in this embodiment, the common terminals of the current transformers 13 are connected in parallel to the positive terminal of the DC output unit, and the negative poles of the capacitor groups 16 under test are connected to the negative terminal of the DC output unit through a leakage current detection unit.

[0036] In this embodiment, the capacitor high temperature load test circuit also includes a DC-isolating AC-isolating inductor 14, one end of which is directly connected to the positive terminal of the DC output unit, and the other end is connected to the common terminal of the current transformer 13.

[0037] In this embodiment, the leakage current detection unit is a leakage current detection resistor 15 , one end of the leakage current detection resistor 15 is connected to the negative terminal of the DC output unit, and the other end is connected to the negative electrode of the capacitor group 16 under test.

[0038] Except for the above implementation, the other implementations in this embodiment are the same as those in the first embodiment.

[0039] In summary, the novel capacitor durability test circuit only needs to provide one DC power supply and one AC power supply, or only one AC / DC integrated machine. Through the current transmission and isolation function of the current transformer, the AC power supply is separated into multiple outputs, which is equivalent to providing multiple AC power supplies; and the primary series connection method of the current transformer is adopted to make the current flowing through the current transformer the same, thereby ensuring that the ripple current on each group of capacitors tested is consistent, achieving the effect of current balancing, and thus ensuring the accuracy of the test results.

[0040] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A new type of capacitor durability test circuit, characterized by: The device comprises an AC output unit, a DC output unit, a plurality of current transformers, a plurality of leakage current detection units, and a plurality of capacitor groups to be tested. A single capacitor group to be tested comprises two capacitors to be tested. The negative electrodes of the two capacitors to be tested are connected, that is, they are connected in reverse series to form a three-terminal device. The AC output unit is provided with two AC output terminals. The DC output unit is provided with two DC output terminals, which are respectively a positive terminal and a negative terminal. The primary side of the current transformer is provided with two primary terminals, which are sequentially connected in series and are respectively connected to the two AC output terminals after being connected in series. The secondary side is provided with two secondary terminals and a common terminal. The common terminals of the current transformers are all connected to the positive terminal of the DC output unit. The negative poles of the capacitor groups under test are connected to the negative terminal of the DC output unit through a leakage current detection unit, and the two positive poles of each capacitor group under test are respectively connected to the two secondary terminals of each current transformer. The leakage current of the capacitor under test is detected in real time by the leakage current detection unit, and the models and specifications of each current transformer are the same; the capacitor high temperature load test circuit also includes a plurality of direct-current isolation inductors, one end of which is connected to the leakage current detection unit, and the other end is directly connected to the negative terminal of the DC output unit; the leakage current detection unit is a leakage current detection resistor, one end of which is connected to the negative pole of the capacitor group under test, and the other end is connected to the direct-current isolation inductor.

2. A novel capacitor durability test circuit according to claim 1, characterized in that: The number of the current transformers, leakage current detection resistors, capacitor groups to be measured, and DC-passing and AC-isolating inductors are all the same.

3. A novel capacitor durability test circuit according to claim 1, characterized in that: The AC output unit and the DC output unit are realized by an AC / DC integrated power supply.

4. A novel capacitor durability test circuit according to claim 1, characterized in that: The AC output unit is an AC power supply, and the DC output unit is a DC power supply.

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