CN116430156A - A high-temperature load test system for precision multi-channel current-sharing capacitors - Google Patents

Abstract

The invention discloses a high-temperature load test system for precision multi-channel current-equalizing capacitors, which belongs to the technical field of high-temperature load tests for capacitors, and includes a power supply module, multiple current transformers, multiple sets of capacitor banks to be tested, and multiple sets of control switch units. The present invention adopts more than two secondary ends of the current transformers to be connected in series and form a loop, so that the primary currents in the current transformers are consistent. In the short-circuit state, the induced voltage in the primary is very small, resulting in very small power consumption of the current transformer, greatly reducing the copper loss and iron loss of the current transformer, making the primary-to-secondary current ratio of the current transformer more accurate and the current sharing effect Better, less energy loss.

Description

A high-temperature load test system for precision multi-channel current-sharing capacitors

technical field

The invention relates to the technical field of high-temperature load testing of capacitors, in particular to a high-temperature load testing system for precision multi-channel current-equalizing type capacitors.

Background technique

The high temperature load test is an important part of the routine test and identification test of capacitors. It assesses the tolerance of capacitors under the combined effects of environmental stress and electrical stress, also known as durability or working life test.

The existing test method is to divide the capacitors into 11 pairs, each pair is connected in reverse series by 2 capacitors, apply DC voltage and ripple voltage to each capacitor, and then put them into a high-temperature oven for testing. The existing test method uses several transformers, the primary windings of each transformer are connected in series, the first and last ends of the primary windings in series are connected to an AC constant current power supply, and the two ends of the secondary windings of each transformer are respectively connected to a contactor. The two ends of the normally open contacts and the central points of the secondary windings of each transformer are all connected to the positive pole of the same DC power supply, and the negative poles of the DC power supply are respectively connected to the negative pole of the capacitor in series with resistors.

In the existing test method, a transformer is used to provide a test current to the capacitor, and the primary windings of the transformer are connected in series to ensure that the currents on multiple groups of capacitors are consistent. As a driving source, the transformer must provide enough ripple voltage and ripple current for the test capacitor, so that the power required by the transformer is very large, and the volume and loss of the transformer are correspondingly increased, and the manufacturing cost is also increased. The above problems need to be solved urgently. For this reason, a high-temperature load test system for precision multi-channel current-sharing capacitors is proposed.

Contents of the invention

The technical problem to be solved by the present invention is: how to solve the problem that the power required by the transformer in the existing method is very large, and the volume and loss of the transformer are correspondingly increased, and a precision multi-channel current sharing capacitor is provided. High temperature load test system.

The present invention solves the above-mentioned technical problems through the following technical solutions. The present invention includes a power supply module, multiple current transformers, multiple sets of measured capacitor banks, and multiple sets of control switch units; Two measured capacitors are connected in series, and the secondary windings of each current transformer are connected end to end to form a loop, so that the currents in the primary windings of the current transformers are consistent, and whether each measured capacitor bank is connected to the circuit is controlled by controlling the switching unit. The power supply module includes an AC output unit, and the ripple voltage and ripple current required by each capacitor under test are provided through the AC output unit.

Furthermore, the number of turns and the physical structure of the primary and secondary windings of each current transformer are the same.

Furthermore, the AC output unit is realized by a transformer T, the two ends of the secondary winding of the transformer T are the first AC output terminal and the second AC output terminal respectively, and the power module also includes a DC output unit, so The DC output unit includes a positive terminal and a negative terminal.

Furthermore, a group of capacitor banks under test includes two capacitors under test, which are respectively the first capacitor under test and the second capacitor under test, and a group of control switch units includes two control switches, respectively the first control switch, the second capacitor under test Second control switch.

Furthermore, each current transformer connected with each set of capacitor banks under test includes a first primary winding, a second primary winding, and a secondary winding, and one end of the first primary winding is connected to the positive pole of the first capacitor under test and the first primary winding. The first terminal of a control switch is connected, one end of the second primary winding is connected with the positive pole of the second capacitor under test and the first terminal of the second control switch, and the negative poles of the first capacitor under test and the second capacitor under test are connected through One resistor is connected to the negative terminal of the DC output unit, the other end of the first primary winding is connected to the second terminal of the first control switch, the other end of the second primary winding is connected to the second terminal of the second control switch, the first control The third terminal of the switch is connected to the first AC output terminal, the third terminal of the second control switch is connected to the second AC output terminal, and the positive terminal of the DC output unit is connected to the AC output unit through the direct current blocking inductance L The intermediate points of the secondary windings are connected; the secondary windings of each current transformer are connected end to end and form a loop.

Furthermore, each current transformer connected to each set of capacitor banks under test includes a primary winding and a secondary winding, and one end of the primary winding is connected to the positive pole of the first capacitor under test and the first terminal of the first control switch , the other end of the primary winding is connected to the second terminal of the first control switch, the third terminal of the first control switch is connected to the first AC output terminal, and the negative electrodes of the first capacitor under test and the second capacitor under test are connected through a The resistor is connected to the negative terminal of the DC output unit, the third terminal of the second control switch is connected to the second AC output terminal, the positive pole of the second measured capacitor is connected to the second terminal of the second control switch, and the third terminal of the second control switch is connected to the second terminal of the second control switch. One terminal is in an open circuit state, and the positive terminal of the DC output unit is connected to the middle point of the secondary winding of the AC output unit through the direct-current blocking inductance L; the secondary windings of each current transformer are connected end to end and form a loop .

Furthermore, each current transformer connected to each group of capacitor banks under test includes a primary winding with a center tap and a secondary winding, one end of the primary winding is connected to the second terminal of the first control switch, and the first The third terminal of the control switch is connected to the negative pole of the first capacitor under test, the positive pole of the first capacitor under test is connected to the first AC output terminal, the other end of the primary winding is connected to the second terminal of the second control switch, and the second control The third terminal of the switch is connected to the negative pole of the second capacitor under test, the positive pole of the second capacitor under test is connected to the second AC output terminal, the first terminal of the first control switch is connected to the first terminal of the second control switch, and the primary The middle tap of the winding is connected to the negative terminal of the DC output unit through a resistor, and the positive terminal of the DC output unit is connected to the middle point of the secondary winding of the AC output unit through the direct-current blocking inductance L; The secondary windings are connected end to end and form a loop.

Furthermore, the control switch is a contactor, and the contactor has three terminals, namely a first terminal, a second terminal and a third terminal, wherein the second terminal is a common terminal, the first terminal is a normally open terminal, and the second terminal is a normally open terminal. The three terminals are normally closed terminals.

Compared with the prior art, the present invention has the following advantages:

In the present invention, the ripple voltage and ripple current required by the measured capacitors are provided by the AC power supply, and the ripple currents in each group of capacitors are kept consistent through the adjustment function of the current transformer in series, and the purpose of current sharing is achieved.

Since the secondary windings of the current transformer are connected end to end and form a loop, the current transformer works in a short-circuit state, and the induced voltage at the primary end of the current transformer is very small, so that the power consumption of the current transformer is also very small, which greatly reduces the The copper loss and iron loss of the current transformer make the primary-to-secondary current ratio of the current transformer more accurate, the current sharing effect is better, and the energy consumption loss is smaller; at the same time, the volume of the current transformer is smaller and the manufacturing cost is lower. Resources are saved.

The system can work continuously, and if a capacitor under test fails, the failed capacitor under test can be removed from the test without affecting other capacitors under test to continue the test, and the striations added to each capacitor under test Wave currents are consistent.

Description of drawings

Fig. 1 is a schematic structural view of a high-temperature load test system for precision multi-channel current-equalizing capacitors in Embodiment 1 of the present invention;

Fig. 2 is a schematic structural view of a high-temperature load test system for precision multi-channel current-equalizing capacitors in Embodiment 2 of the present invention;

Fig. 3 is a schematic structural diagram of a high-temperature load test system for precision multi-channel current-equalizing capacitors in Embodiment 3 of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Embodiment one

As shown in Figure 1, this embodiment provides a technical solution: a high-temperature load test system for precision multi-channel current-sharing type capacitors, including a power module, multiple current transformers (T1~nT1, n in total), multiple groups Capacitor banks under test (1CX1~nCX1 and 1CX2~nCX2, among them, capacitors under test 1CX1 and capacitor under test 1CX2 form a group of capacitor banks under test, and so on, a total of n groups), multiple sets of control switch units (the number is 2n one capacitor under test corresponds to one control switch); the primary windings of each current transformer are connected in series with two capacitors under test in a single group, and the secondary windings of each current transformer are connected end to end to form a loop to make the current mutual inductance The current in the primary winding of the device is consistent, and the control switch unit is used to control whether each capacitor bank under test is connected to the circuit. The power module includes an AC output unit, and the ripple voltage and ripple current required by each capacitor under test pass through the provided by the AC output unit described above.

In this embodiment, the number of turns and the physical structure of the primary and secondary windings of each current transformer are the same.

In this embodiment, the AC output unit is realized by a transformer T, and the two ends of the secondary winding of the transformer T are respectively the first AC output terminal (AC1) and the second AC output terminal (AC2). The module also includes a DC output unit, which includes a positive terminal and a negative terminal.

In this embodiment, a set of capacitor banks under test includes two capacitors under test, which are respectively the first capacitor under test and the second capacitor under test, and a set of control switch units includes two control switches, respectively the first control switch switch, the second control switch; each current transformer (T1～nT1) connected with each group of measured capacitor banks includes a first primary winding, a second primary winding, and a secondary winding, and the N2 terminal of the first primary winding is connected to The positive pole of the capacitor under test CX1 (the first capacitor under test) is connected to the first terminal (terminal 1) of the first control switch, and the terminal N5 of the second primary winding is connected to the positive pole of the capacitor under test CX2 (the second capacitor under test) and The first terminal of the second control switch is connected, the negative poles of the measured capacitor CX1 and the measured capacitor CX2 are connected to the negative terminal of the DC output unit through a resistor (R1), and the N1 end of the first primary winding is connected to the first control switch. The second terminal (terminal 2) of the second primary winding is connected to the second terminal of the second control switch, the third terminal (terminal 3) of the first control switch is connected to the first AC output terminal, and the second The third terminal of the control switch is connected to the second AC output terminal, and the unit positive terminal of the DC output is connected to the middle point of the secondary winding of the AC output unit through the direct-current blocking inductance L; the secondary winding of each current transformer The primary windings are connected end to end and form a loop.

In this embodiment, the control switch is a contactor (1J1-nJ1 and 1J2-nJ2, wherein the control switch 1J1 and the control switch 1J2 form a group of control switch units, and so on, a total of n groups), and the contactor has three The terminals are respectively a first terminal, a second terminal and a third terminal, wherein the second terminal is a common terminal, the first terminal is a normally open terminal, and the third terminal is a normally closed terminal.

Embodiment two

As shown in FIG. 2 , this embodiment is a first modification of Embodiment 1. Different from the structure of the current transformer in Embodiment 1, the current transformer in this application has only one primary winding.

In this embodiment, a set of capacitor banks under test includes two capacitors under test, which are respectively the first capacitor under test and the second capacitor under test, and a set of control switch units includes two control switches, respectively the first control switch switch, the second control switch; each current transformer (T1~nT1) connected to each group of capacitor banks under test includes a primary winding and a secondary winding, and the N2 terminal of the primary winding is connected to the capacitor CX1 under test (the first The positive pole of the measuring capacitor) is connected to the first terminal of the first control switch, the N1 terminal of the primary winding is connected to the second terminal of the first control switch, the third terminal of the first control switch is connected to the first AC output terminal, and the measured After the negative poles of the capacitor CX1 and the capacitor under test CX2 (the second capacitor under test) are connected, they are connected to the negative terminal of the DC output unit through a resistor (R1), and the third terminal of the second control switch is connected to the second AC output terminal. The anode of the measuring capacitor CX2 is connected to the second terminal of the second control switch, and the first terminal of the second control switch is in an open circuit state, and the positive terminal of the DC output unit is connected to the AC output unit through the DC blocking inductance L. The intermediate points of the secondary windings are connected; the secondary windings of each current transformer are connected end to end and form a loop.

Except for the above-mentioned implementation manner, other implementation manners in this embodiment are the same as Embodiment 1.

Embodiment three

As shown in Figure 3, this embodiment is the second modification of Embodiment 1. Different from the structure of the current transformer in Embodiment 1, the current transformer in this application has only one primary winding, and the primary winding has Middle tap.

In this embodiment, a set of capacitor banks under test includes two capacitors under test, which are respectively the first capacitor under test and the second capacitor under test, and a set of control switch units includes two control switches, respectively the first control switch switch, the second control switch; each current transformer (T1~nT1) connected to each group of measured capacitor banks includes a primary winding with a middle tap, a secondary winding, and the N1 terminal of the primary winding is connected to the first control The second terminal of the switch is connected, the third terminal of the first control switch is connected to the negative pole of the measured capacitor CX1, the positive pole of the measured capacitor CX1 is connected to the first AC output terminal, and the N2 terminal of the primary winding is connected to the second terminal of the second control switch. The two terminals are connected, the third terminal of the second control switch is connected to the negative pole of the capacitor CX2 under test, the positive pole of the capacitor CX2 under test is connected to the second AC output terminal, the first terminal of the first control switch is connected to the first terminal of the second control switch One-terminal connection, the N7 end (middle tap) of the primary winding is connected to the negative terminal of the DC output unit through a resistor (R1), and the positive terminal of the DC output unit is connected to the AC output unit through the direct-current blocking inductance L The intermediate points of the secondary windings are connected; the secondary windings of each current transformer are connected end to end and form a loop.

Except for the above-mentioned implementation manner, other implementation manners in this embodiment are the same as Embodiment 1.

To sum up, in the high-temperature load test system for precision multi-channel current sharing type capacitors in the above embodiment, more than two secondary ends of current transformers are connected in series end to end to form a loop, so that the primary currents in the current transformers are consistent At the same time, because the secondary of the current transformer forms a loop, the current transformer works in a short-circuit state, and the induced voltage in the primary is very small, resulting in very small power consumption of the current transformer, which greatly reduces the copper loss of the current transformer and iron loss, making the primary-to-secondary current ratio of the current transformer more accurate, the current sharing effect better, and the energy consumption loss smaller.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (8)

1. A high-temperature load test system for precision multi-channel current-equalizing capacitors, characterized in that it comprises a power supply module, a plurality of current transformers, a plurality of groups of measured capacitor banks, and a plurality of control switch units; the primary windings of each current transformer They are respectively connected in series with two measured capacitors in a single group, and the secondary winding of each current transformer is connected end to end to form a loop, so that the current in the primary winding of the current transformer is consistent, and each measured capacitor group is controlled by controlling the switching unit Whether connected to the circuit, the power module includes an AC output unit, and the ripple voltage and ripple current required by each capacitor under test are provided through the AC output unit. 2. A high-temperature load test system for precision multi-channel current sharing type capacitors according to claim 1, characterized in that: the number of turns and the physical structure of the primary and secondary windings of each current transformer are the same. 3. A high-temperature load test system for precision multi-channel current-equalizing capacitors according to claim 2, characterized in that: the AC output unit is realized by a transformer T, and the two ends of the secondary winding of the transformer T are respectively The first AC output terminal and the second AC output terminal, the power module further includes a DC output unit, and the DC output unit includes a positive terminal and a negative terminal. 4. A high-temperature load test system for precision multi-channel current-equalizing capacitors according to claim 3, characterized in that: one set of capacitor banks under test includes two capacitors under test, namely the first capacitor under test and the capacitor under test respectively. Two capacitors to be tested, a group of control switch units include two control switches, which are respectively the first control switch and the second control switch. 5. The high-temperature load test system for precision multi-channel current-sharing type capacitors according to claim 4, characterized in that: each current transformer connected to each group of capacitor banks to be tested includes a first primary winding, a second primary winding winding, a secondary winding, one end of the first primary winding is connected to the positive pole of the first capacitor under test and the first terminal of the first control switch, one end of the second primary winding is connected to the positive pole of the second capacitor under test and the second control switch The first terminal of the switch is connected, the negative poles of the first capacitor under test and the second capacitor under test are connected to the negative pole terminal of the DC output unit through a resistor, and the other end of the first primary winding is connected to the second terminal of the first control switch The other end of the second primary winding is connected to the second terminal of the second control switch, the third terminal of the first control switch is connected to the first AC output terminal, the third terminal of the second control switch is connected to the second AC output terminal connected, the positive terminal of the DC output unit is connected to the middle point of the secondary winding of the AC output unit through the DC blocking inductance L; the secondary windings of each current transformer are connected end to end and form a loop. 6. A high-temperature load test system for precision multi-channel current sharing type capacitors according to claim 4, characterized in that: each current transformer connected to each group of capacitor banks to be tested includes a primary winding and a secondary winding , one end of the primary winding is connected to the positive pole of the first capacitor under test and the first terminal of the first control switch, the other end of the primary winding is connected to the second terminal of the first control switch, and the third terminal of the first control switch is connected to the first terminal of the first control switch. One AC output terminal is connected, the negative poles of the first capacitor under test and the second capacitor under test are connected and then connected to the negative pole terminal of the DC output unit through a resistor, the third terminal of the second control switch is connected with the second AC output terminal, and the second The anodes of the two measured capacitors are connected to the second terminal of the second control switch, the first terminal of the second control switch is in an open circuit state, and the positive terminal of the DC output unit is connected to the AC output unit through the direct current blocking inductance L The intermediate point of the secondary winding of each current transformer is connected; the secondary windings of each current transformer are connected end to end and form a loop. 7. A high-temperature load test system for precision multi-channel current-sharing type capacitors according to claim 4, characterized in that: each current transformer connected to each group of capacitor banks to be tested includes a primary winding with an intermediate tap , a secondary winding, one end of the primary winding is connected to the second terminal of the first control switch, the third terminal of the first control switch is connected to the negative pole of the first capacitor under test, and the positive pole of the first capacitor under test is connected to the first AC The other end of the primary winding is connected to the second terminal of the second control switch, the third terminal of the second control switch is connected to the negative pole of the second capacitor under test, and the positive pole of the second capacitor under test is connected to the second AC output terminal connection, the first terminal of the first control switch is connected to the first terminal of the second control switch, the middle tap of the primary winding is connected to the negative terminal of the DC output unit through a resistor, and the positive terminal of the DC output unit is passed through The AC isolation inductance L is connected to the intermediate point of the secondary winding of the AC output unit; the secondary windings of the current transformers are connected end to end to form a loop. 8. A high-temperature load test system for precision multi-channel current sharing type capacitors according to claim 5, 6 or 7, characterized in that: the control switch is a contactor, and the contactor has three terminals, which are respectively the first terminal , the second terminal and the third terminal, wherein the second terminal is a common terminal, the first terminal is a normally open terminal, and the third terminal is a normally closed terminal.

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