General control interface system for AC drive system test bed converter

Abstract

This invention discloses a universal control interface system for converters used in AC drive system test benches, comprising a control unit, a main disconnection status signal circuit, a synchronization signal circuit, a mains current signal circuit, and a VCB enable signal circuit. The main disconnection status signal circuit includes a normally open contact status circuit, a normally closed contact status circuit, a second switch, a first rotary switch, and a second rotary switch. One end of the normally open contact status circuit is connected to multiple normally open main disconnection contacts connected in parallel, and one end of the normally closed contact status circuit is connected to multiple normally closed main disconnection contacts connected in series. The normally open contacts of the second switch are connected in parallel to the normally open contact status circuit, and the normally closed contacts are connected in series to the normally closed contact status circuit. The second rotary switch is located in the normally closed contact status circuit and is connected in parallel with one or more normally closed main disconnection contacts. This invention has advantages such as enabling interface conversion between different test bench main circuit topologies and different test samples, improving test efficiency, and enhancing the modularity of test bench design.

Description

Technical Field

[0001] This invention mainly relates to the field of AC drive system testing technology, specifically to a universal control interface system for AC drive system test benches. Background Technology

[0002] The AC drive system test bench is mainly used for combined testing of the traction systems of various AC drive EMUs and electric locomotives in rail transit. The traction system mainly includes traction transformers, traction converters, traction motors, and control devices. The test bench provides the same power supply conditions and similar load performance as the actual train.

[0003] According to the test requirements, the test bench needs to provide the corresponding control signals for the traction converter under test, including control power supply, synchronization signal, main disconnection status signal and VCB enable signal.

[0004] Due to differences in actual needs and design principles, the power supply main circuit topology of the traction system under test provided by the test bench is not entirely the same, resulting in inconsistencies in the control signal interfaces. Furthermore, different traction converters under test have different requirements for control signals, necessitating corresponding changes to the test bench's control signals to adapt to these varying requirements.

[0005] Currently, the main power supply circuit topology of existing test benches is mainly divided into the following four categories, such as Figure 1 As shown, the main differences between the various topologies are as follows:

[0006] a) No network voltage interruption function, QF1 simulates the actual train VCB, and the network voltage measurement PT is at the front end of the VCB;

[0007] b) It has a grid voltage interruption function. QF1 and QF2 simultaneously simulate the actual train VCB and pantograph. The grid voltage measurement PT is located at the front end of the VCB.

[0008] c) It has a grid voltage interruption function. QF1 and QF2 simultaneously simulate the actual train VCB and pantograph. The grid voltage measurement PT is located at the rear end of the VCB.

[0009] d) It has a grid voltage interruption function. QF1 and QF2 simulate the actual train pantograph, QF3 simulates the actual train VCB, and the grid voltage measurement PT is between the pantograph and VCB.

[0010] Of the four topologies above, topology a) has a single function and cannot perform grid voltage interruption tests; topology b) can realize the power supply sequence of the actual vehicle with grid voltage first and then VCB connected, but the grid voltage signal cannot be directly interrupted synchronously during grid voltage interruption tests, and the main disconnection status signal will be interrupted; topology c) can realize the synchronous direct interruption of the grid voltage signal during grid voltage interruption tests, but the main disconnection status signal will be interrupted, and it cannot realize the power supply sequence of the actual vehicle with grid voltage first and then VCB connected, requiring modification of the tested traction converter program for testing; topology d) can completely simulate the power supply topology of the actual vehicle, but the number of devices increases and the cost is the highest.

[0011] In summary, existing AC drive system test benches lack a standardized design for the control interface with the converter under test. Generally, some control interfaces are integrated in the main circuit wiring cabinet. To meet the usage and testing needs of different main circuit power supply topologies, different converter under test requirements, and special requirements of grid voltage interruption tests, manual wiring changes and temporary modifications to the converter under test programs are used. This approach cannot fully simulate actual circuit conditions, affects test results, and the circuits are prone to errors, are not safe enough, and have very low testing efficiency. Summary of the Invention

[0012] The technical problem to be solved by this invention is: in view of the problems existing in the prior art, this invention provides a universal control interface system for AC drive system test benches that realizes interface conversion for different test bench main circuit topologies and different test objects.

[0013] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0014] A universal control interface system for a converter in an AC drive system test bench includes a control unit, a DC power supply, a switching power supply, a main disconnection status signal circuit, a synchronization signal circuit, a grid current signal circuit, and a VCB enable signal circuit. The input terminals of the DC power supply and the switching power supply are both connected to the control power supply of the AC drive system test bench. The output terminal of the DC power supply is connected to the converter under test, and the output terminal of the switching power supply is connected to the control unit.

[0015] The main disconnection status signal circuit includes a normally open contact status circuit, a normally closed contact status circuit, a second switch, a first rotary switch, and a second rotary switch. One end of the normally open contact status circuit is connected to multiple normally open main disconnection contacts connected in parallel, and one end of the normally closed contact status circuit is connected to multiple normally closed main disconnection contacts connected in series. The normally open contacts of the second switch are connected in parallel to the normally open contact status circuit, and the normally closed contacts of the second switch are connected in series to the normally closed contact status circuit. The control unit is connected to the second switch and is used to control the second switch to close during the interruption test to achieve the holding and locking of the current main disconnection status.

[0016] The output terminal of the DC power supply is connected to the normally open contact state circuit and the normally closed contact state circuit through the first rotary switch. The active or passive nature of the main disconnection state signal is realized by switching the first rotary switch on and off.

[0017] The second rotary switch is located in the normally closed contact state circuit and is connected in parallel with one or more normally closed main break contacts. The main break state signal is short-circuited by switching the second rotary switch on and off.

[0018] As a further improvement to the above technical solution:

[0019] The synchronization signal circuit includes a PT signal circuit, a main break contact circuit, and a third switch. The third switch is connected to the control unit. One end of the PT signal circuit is connected to the PT signal of the main circuit of the AC drive system test bench. The main break contact circuit includes multiple sets of normally open main break contact interfaces. One end of the multiple sets of normally open main break contact interfaces is connected to multiple sets of parallel main break contacts, and the other end is connected in parallel with the normally closed contact of the third switch and then connected in series to the PT signal circuit.

[0020] The grid current signal circuit includes a fourth switch, which is connected to the control unit. One end of the grid current signal circuit is connected to the CT signal of the main circuit of the AC drive system test bench. A set of normally closed contacts of the fourth switch are connected in parallel in the grid current signal circuit to achieve a short circuit in the circuit. A set of normally closed contacts of the fourth switch achieves a ground connection in the circuit.

[0021] One end of the VCB enable signal circuit receives the VCB enable signal from the converter under test, providing a closing permission signal and a fault trip signal to the main circuit breaker of the AC drive system test bench. The VCB enable signal circuit includes a fifth switch and a sixth switch, expanding one set of normally open VCB enable signal contacts into two sets of passive normally open contacts and two sets of passive normally closed contacts. The two sets of passive normally open contacts are used for the closing permission control circuits of the two main circuit breakers, and the two sets of passive normally closed contacts are used for the fault trip control circuits of the two main circuit breakers. The coils and corresponding contacts of the fifth and sixth switches are all connected to the control unit.

[0022] It also includes a communication interface for remote control and status monitoring of the control unit and DC power supply of the AC drive system test bench.

[0023] The communication interface is an Ethernet communication interface.

[0024] It also includes a first switch, which is connected to the control unit; a main switch is provided between the output terminal of the DC power supply and the tested converter, and the first switch is connected to the main switch.

[0025] The second switch is an intermediate relay.

[0026] The control unit is a PLC or a microcontroller.

[0027] It also includes a housing, in which the control unit, DC power supply, switching power supply, main disconnection status signal circuit, synchronization signal circuit, mains current signal circuit and VCB enable signal circuit are all integrated.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] This invention, through the integrated and universal design of the control interface, and by employing a series of software and hardware conversion controls such as control units and hard-wired interlocks, realizes the interface conversion of different test bench main circuit topologies and different test objects. It achieves the consistency and synchronization of the actual vehicle operating condition signal simulation of the grid voltage interruption test of the test converter, which is beneficial to the modular and universal design of AC drive system test benches, and can also improve test efficiency and ensure test safety to a certain extent.

[0030] This invention solves the problem of control interface conversion between AC drive system test bench and the test converter. It is applicable to several typical test bench circuit topologies and different types of test converter signal requirements. It can be used as a standard product in the research and development of test benches, improving the modularity of test bench design. Attached Figure Description

[0031] Figure 1 This is a topology diagram of the four types of main power supply circuits for the test bench in the existing technology.

[0032] Figure 2 This is a circuit schematic diagram of the system of the present invention in an embodiment. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] like Figure 2 As shown, the AC drive system test bench universal control interface system for converters in this embodiment of the invention includes a control unit (such as a PLC), an adjustable DC power supply G1, a switching power supply G2, a main disconnection status signal circuit, a synchronization signal circuit, a grid current signal circuit, and a VCB enable signal circuit (where VCB: Vacuum Circuit Breaker). The input terminals of the DC power supply and the switching power supply are both connected to the control power supply of the AC drive system test bench. The output terminal of the DC power supply is connected to the converter under test, and the output terminal of the switching power supply is connected to the control unit.

[0035] Specifically, the test bench is supplied with AC220V control power through circuit breaker QF1 to power adjustable DC power supply G1 and switching power supply G2. Adjustable DC power supply G1 provides DC110V control power to the converter under test, which can realize voltage regulation function. Its output can realize power-off reset operation control through the opening and closing of the main switch (such as contactor KM1). Switching power supply G2 provides working power to the control unit.

[0036] The main disconnection status signal circuit provides the main disconnection status signal to the converter under test, including normally open contact status circuit, normally closed contact status circuit, second switch (intermediate relay KA2), first rotary switch SA1 and second rotary switch SA2; due to the diversity of the main circuit topology of the AC drive system test bench, there may be one or two main disconnections, so four sets of main disconnection contact input interfaces are provided, of which two sets of normally open main disconnection contacts are connected in parallel, and two sets of normally closed main disconnection contacts are connected in series. One end of the normally open contact status circuit is connected to multiple normally open main disconnection contacts in parallel, and one end of the normally closed contact status circuit is connected to multiple normally closed main disconnection contacts in series.

[0037] Since there are two main circuit breakers, the main circuit breaker state will also be interrupted when the converter under test is subjected to grid voltage interruption test, which does not conform to the actual line operating conditions. Therefore, the normally open contacts of the second switch are connected in parallel to the normally open contact state circuit, and the normally closed contacts are connected in series to the normally closed contact state circuit. The control unit is connected to the second switch and is used to control the second switch to close during the interruption test to achieve the current main circuit breaker state to be locked. During other normal tests, the second switch KA2 does not operate.

[0038] Since different tested converters have different requirements for the main disconnection status signal, which are mainly divided into two types: active signal and passive signal, the positive terminal of the DC110V control power supply is introduced into the normally open contact status circuit and the normally closed contact status circuit respectively through the first rotary switch SA1. Manually closing SA1 can make the main disconnection status signal active, and manually opening SA1 can make the main disconnection status signal passive.

[0039] In addition, the second rotary switch SA2 is located in the normally closed contact state circuit and is connected in parallel with one or more normally closed main disconnect contacts. The main disconnect status signal is short-circuited by opening and closing the second rotary switch. When there is one main disconnect, the main disconnect status signal can be switched by manually closing SA2. When there are two main disconnects, the main disconnect status signal can also be switched by manually opening SA2.

[0040] In one specific embodiment, the synchronization signal circuit provides a synchronization signal to the converter under test (DUT), transferring the PT (voltage transformer) signal from the main circuit of the AC drive system test bench to the DUT after protection by circuit breaker QF2. The synchronization signal circuit includes a PT signal circuit, a main contact circuit, and a third switch. The third switch is connected to the control unit. One end of the PT signal circuit is connected to the PT signal of the main circuit of the AC drive system test bench. The main contact circuit includes multiple sets of normally open main contact interfaces. One end of each set of normally open main contact interfaces is connected to multiple sets of parallel main contact interfaces, and the other end is connected in parallel with the normally closed contact of the third switch and then connected in series to the PT signal circuit. Due to the diversity of the main circuit topology of the AC drive system test bench, when the main circuit is... Figure 1 In topology b), when the converter under test is subjected to a grid voltage interruption test, the synchronization signal cannot follow the interruption synchronously when the interruption occurs, which does not conform to the actual line operating conditions. Therefore, a third switch (intermediate relay KA3) is added. During the interruption test, after the main disconnect is closed, the control unit controls KA3 to open its normally closed contact, so that the two sets of normally open main disconnect contacts participate in the circuit control. At this time, the synchronization signal can also follow the interruption synchronously when the interruption occurs, which meets the test requirements. During other normal tests, KA3 does not operate to ensure that the synchronization signal is normal.

[0041] In one specific embodiment, the grid current signal loop provides a grid current signal to the converter under test (DUT), directly transferring the CT (current transformer) signal in the main circuit of the AC drive system test bench to the DUT. Since different DUTs may not require a grid current signal, the CT output signal circuit needs to be short-circuited and grounded when not in use to ensure safety. Therefore, a fourth switch (such as intermediate relay KA4) is added. Two sets of normally closed contacts respectively realize the short-circuit and grounding connection of the CT output signal circuit. When not in use, it is short-circuited and grounded by default. If it needs to be enabled, the intermediate relay KA4 is controlled by the control unit to open, disconnecting the short-circuit and grounding circuit.

[0042] In one specific embodiment, the VCB enable signal circuit receives the VCB enable signal from the converter under test, providing a closing permission signal and a fault trip signal to the main circuit breaker of the AC drive system test bench. Due to the diversity of the main circuit topology of the AC drive system test bench, there may be one or two main circuit breakers. Therefore, a fifth switch (such as intermediate relay KA5) and a sixth switch (such as intermediate relay KA6) are added to expand one set of normally open contacts for the VCB enable signal into two sets of passive normally open contacts and two sets of passive normally closed contacts. The two sets of passive normally open contacts are used for the closing permission control circuits of the two main circuit breakers, and the two sets of passive normally closed contacts are used for the fault trip control circuits of the two main circuit breakers. Furthermore, the status of intermediate relays KA5 and KA6 is collected in the control unit for VCB enable signal monitoring.

[0043] In one specific embodiment, the control unit, DC power supply, switching power supply, main disconnection status signal circuit, synchronization signal circuit, network current signal circuit, and VCB enable signal circuit are all integrated into a single enclosure. The enclosure is also equipped with an Ethernet communication interface, enabling the AC drive system test bench to remotely control and monitor the control unit and adjustable DC power supply within the interface enclosure. Of course, in other embodiments, the enclosure can be replaced by integration with other electrical cabinets; or the Ethernet communication interface can be replaced by other communication methods.

[0044] This invention, through the integrated and universal design of the control interface, and by employing a series of software and hardware conversion controls such as control units and hard-wired interlocks, realizes the interface conversion of different test bench main circuit topologies and different test objects. It achieves the consistency and synchronization of the actual vehicle operating condition signal simulation of the grid voltage interruption test of the test converter, which is beneficial to the modular and universal design of AC drive system test benches, and can also improve test efficiency and ensure test safety to a certain extent.

[0045] This invention solves the problem of control interface conversion between AC drive system test bench and the test converter. It is applicable to several typical test bench circuit topologies and different types of test converter signal requirements. It can be used as a standard product in the research and development of test benches, improving the modularity of test bench design.

[0046] As shown in this disclosure and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. The terms "connected" or "linked" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect.

[0047] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A universal control interface system for a converter used in an AC drive system test bench, characterized in that, It includes a control unit, a DC power supply, a switching power supply, a main disconnection status signal circuit, a synchronization signal circuit, a mains current signal circuit, and a VCB enable signal circuit. The input terminals of the DC power supply and the switching power supply are both connected to the control power supply of the AC drive system test bench. The output terminal of the DC power supply is connected to the converter under test, and the output terminal of the switching power supply is connected to the control unit. The main disconnection status signal circuit provides a main disconnection status signal to the converter under test. The main disconnection status signal circuit includes a normally open contact status circuit, a normally closed contact status circuit, a second switch, a first rotary switch, and a second rotary switch. One end of the normally open contact status circuit is connected to multiple normally open main disconnection contacts connected in parallel, and one end of the normally closed contact status circuit is connected to multiple normally closed main disconnection contacts connected in series. The normally open contacts of the second switch are connected in parallel to the normally open contact status circuit, and the normally closed contacts of the second switch are connected in series to the normally closed contact status circuit. The control unit is connected to the second switch and is used to control the second switch to close during test interruption to maintain and lock the current main disconnection status. The output terminal of the DC power supply is connected to the normally open contact state circuit and the normally closed contact state circuit through the first rotary switch. The active or passive nature of the main disconnection state signal is realized by switching the first rotary switch on and off. The second rotary switch is located in the normally closed contact state circuit and is connected in parallel with one or more normally closed main break contacts. The main break state signal is short-circuited by switching the second rotary switch on and off.

2. The universal control interface system for AC drive system test benches according to claim 1, characterized in that, The synchronization signal circuit includes a PT signal circuit, a main break contact circuit, and a third switch. The third switch is connected to the control unit. One end of the PT signal circuit is connected to the PT signal of the main circuit of the AC drive system test bench. The main break contact circuit includes multiple sets of normally open main break contact interfaces. One end of the multiple sets of normally open main break contact interfaces is connected to multiple sets of parallel main break contacts, and the other end is connected in parallel with the normally closed contact of the third switch and then connected in series to the PT signal circuit.

3. The universal control interface system for AC drive system test benches according to claim 1, characterized in that, The grid current signal circuit includes a fourth switch, which is connected to the control unit. One end of the grid current signal circuit is connected to the CT signal of the main circuit of the AC drive system test bench. A set of normally closed contacts of the fourth switch are connected in parallel in the grid current signal circuit to achieve a short circuit in the circuit. A set of normally closed contacts of the fourth switch achieves a ground connection in the circuit.

4. The universal control interface system for AC drive system test benches according to claim 1, characterized in that, One end of the VCB enable signal circuit receives the VCB enable signal from the converter under test, providing a closing permission signal and a fault trip signal to the main circuit breaker of the AC drive system test bench. The VCB enable signal circuit includes a fifth switch and a sixth switch, expanding one set of normally open VCB enable signal contacts into two sets of passive normally open contacts and two sets of passive normally closed contacts. The two sets of passive normally open contacts are used for the closing permission control circuits of the two main circuit breakers, and the two sets of passive normally closed contacts are used for the fault trip control circuits of the two main circuit breakers. The coils and corresponding contacts of the fifth and sixth switches are all connected to the control unit.

5. The universal control interface system for AC drive system test benches according to any one of claims 1 to 4, characterized in that, It also includes a communication interface for remote control and status monitoring of the control unit and DC power supply of the AC drive system test bench.

6. The universal control interface system for AC drive system test benches according to claim 5, characterized in that, The communication interface is an Ethernet communication interface.

7. The universal control interface system for AC drive system test benches according to any one of claims 1 to 4, characterized in that, It also includes a first switch, which is connected to the control unit; a main switch is provided between the output terminal of the DC power supply and the tested converter, and the first switch is connected to the main switch.

8. The universal control interface system for AC drive system test benches according to any one of claims 1 to 4, characterized in that, The second switch is an intermediate relay.

9. The universal control interface system for AC drive system test benches according to any one of claims 1 to 4, characterized in that, The control unit is a PLC or a microcontroller.

10. The universal control interface system for AC drive system test benches according to any one of claims 1 to 4, characterized in that, It also includes a housing, in which the control unit, DC power supply, switching power supply, main disconnection status signal circuit, synchronization signal circuit, mains current signal circuit and VCB enable signal circuit are all integrated.

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