Multi-group PCS module parallel connection twin trawling test system

Abstract

The utility model discloses a multi-group PCS module parallel trawling test system comprising a PCS to-be-tested unit, the direct current side of the PCS to-be-tested unit is connected with a direct current source, the alternating current side of the PCS to-be-tested unit is connected with one end of an inductor, the other end of the inductor is connected with one side of a transformer, one end of a resistor is connected between the inductor and one side of the transformer, and the other end of the resistor is connected with the other side of the transformer. The other side of the transformer is connected with an AC power supply. The inductor is connected with the PCS module in series, so that when the inductive reactance of the inductor is far greater than the equivalent impedance of the PCS module, the generation of circulating current can be inhibited to a certain extent; the resistance is connected in parallel at the PCC point, so that the system damping can be increased, the influence of resonance on the test loop can be reduced, the PCS modules to be tested are connected in parallel, and corresponding equipment measures for inhibiting resonance and circulating current are arranged to realize many-to-many twin-drag tests such as two-to-two, three-to-three and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy storage converters, and in particular relates to a parallel-connected drag test system for multiple groups of PCS modules. Background Art

[0002] A power conversion system (PCS) is a critical device that extracts or stores energy from various energy storage devices, such as batteries, supercapacitors, and fuel cells, into the power grid or load. In modern energy systems, PCSs play a vital role, balancing grid loads, improving energy efficiency, increasing the penetration of renewable energy, and regulating the frequency and voltage of power systems. Their performance often significantly impacts related energy storage products, such as the batteries. Therefore, efficient PCS performance testing and verification, while ensuring quality, is crucial.

[0003] Existing technology connects the AC and DC sides of two PCS modules under test separately to form a closed loop. A DC power source is then connected to the DC side. This prevents fault current from being introduced into the grid if the PCS under test is directly connected to the grid. It also enables power to be exchanged between the two PCS modules to test PCS performance. This approach only allows for simultaneous testing and verification of two PCS modules. When there are a large number of modules under test, the one-to-one module pairing test mode is relatively inefficient. Utility Model Content

[0004] The utility model aims to overcome the problem that verification tests of multiple groups of PCS modules cannot be performed in the same test loop, and proposes a parallel-connected test system for multiple groups of PCS modules.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A parallel-connected drag test system for multiple groups of PCS modules includes a PCS unit to be tested, wherein the DC side of the PCS unit to be tested is connected to a DC source, the AC side of the PCS unit to be tested is connected to one end of an inductor, the other end of the inductor is connected to one side of a transformer, one end of a resistor is connected between the inductor and one side of the transformer, and the other side of the transformer is connected to an AC power source.

[0007] Furthermore, several pairs of PCS units under test are provided.

[0008] Furthermore, each pair of PCS test units includes a plurality of PCS modules to be tested, the DC sides of the plurality of PCS modules to be tested are connected, and the connected DC sides are connected to a DC source.

[0009] Furthermore, each pair of PCS units under test includes two PCS modules under test, and each pair of PCS units under test is connected to several inductors, the number of inductors is the same as the number of PCS modules under test, and the AC side of each PCS module under test is connected to one end of an inductor, and the other ends of several inductors are connected.

[0010] Furthermore, critical coupling points of several inductors are connected to one side of the transformer.

[0011] Furthermore, the transformer adopts a three-winding transformer.

[0012] Furthermore, a filter is connected between the other side of the transformer and the AC power supply.

[0013] Furthermore, the filter adopts an LC filter.

[0014] Furthermore, the other end of the resistor is grounded.

[0015] Furthermore, the AC power source is a power grid.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects:

[0017] The utility model proposes a parallel drag test system for multiple groups of PCS modules. By connecting inductors in series with PCS modules, when the inductive reactance is much larger than the equivalent impedance of the PCS modules, the generation of circulating current can be suppressed to a certain extent. By connecting resistors in parallel at the PCC point, the system damping can be increased to reduce the impact of resonance on the test circuit. The utility model realizes two-to-two, three-to-three and other multi-to-many drag tests by connecting the PCS modules to be tested in parallel and setting corresponding equipment measures to suppress resonance and circulating current.

[0018] This utility model proposes a parallel-connected test system for multiple PCS modules, which enables simultaneous verification testing of multiple PCS modules, speeds up PCS module detection efficiency, and realizes mass production verification of power modules. It also addresses the main issues faced by the parallel-connected test method for multiple PCS modules: first, circulating currents are generated after the PCS modules are connected in parallel to form a loop, affecting test results and data verification; second, the complex impedance of the PCS modules themselves and the circuits can cause resonance in the operating loop, significantly affecting the stability of the test loop. This effect is exacerbated when multiple PCS modules are connected in parallel. This utility model can eliminate the adverse effects of circulating currents and resonances generated by parallel-connected PCS modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 This is a structural diagram of a parallel towing test system for multiple groups of PCS modules according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] Example

[0024] A parallel-connected drag test system for multiple groups of PCS modules includes a PCS unit to be tested, wherein the DC side of the PCS unit to be tested is connected to a DC source, the AC side of the PCS unit to be tested is connected to one end of an inductor, the other end of the inductor is connected to one side of a transformer, one end of a resistor is connected between the inductor and one side of the transformer, and the other side of the transformer is connected to an AC power source.

[0025] Preferably, several pairs of PCS units to be tested are provided, each pair of PCS units to be tested includes several PCS modules to be tested, the DC sides of the several PCS modules to be tested are connected, and the connected DC sides are connected to a DC source, each pair of PCS units to be tested includes two PCS modules to be tested, each pair of PCS units to be tested is connected to several inductors, the number of inductors is the same as the number of PCS modules to be tested, the AC side of each PCS module to be tested is connected to one end of an inductor, the other ends of several inductors are connected, the critical coupling points of several inductors are connected to one side of a transformer, and the transformer adopts a three-winding transformer. A three-winding transformer refers to a transformer with three windings per phase, and these three windings are respectively a high-voltage winding, a medium-voltage winding, and a low-voltage winding. A three-winding transformer is usually used in load situations that require two different voltage levels, such as power plants and substations. Its working principle is also based on electromagnetic induction. When one winding is connected to an AC power supply, the other two windings will induce different potentials, thereby realizing voltage conversion. The three-winding transformer has a compact structure, which can reduce the equipment footprint and investment cost, while improving the flexibility and reliability of the power system.

[0026] Preferably, a filter is connected between the other side of the transformer and the AC power supply. The filter is an LC filter. An LC filter, also known as a passive filter, is a filter circuit designed using a combination of inductors (L) and capacitors (C). It uses passive components such as inductors, capacitors, and resistors to filter out one or more harmonics. This filter has a simple structure and is easy to implement. It is the most common and easily adopted passive filter structure.

[0027] Preferably, the other end of the resistor is grounded, and the AC power source is the power grid. The power grid is a whole composed of substations and transmission and distribution lines of various voltage levels, which is used to realize the transmission, conversion, distribution and use of electric energy. It includes multiple links such as power generation, transmission, transformation, distribution and power consumption, and is a complex and huge system. The power grid can be classified according to its coverage and functional characteristics, mainly including the following categories: inter-regional power grid: this type of power grid mainly supplies power from large power points to distant places over long distances; regional power grid: power allocation within a large area; distribution power grid: power grid for power dispatching in a local area; power supply power grid: power grid that provides power to each user.

[0028] Resistance, usually represented by "R", is a physical quantity that represents the magnitude of a conductor's resistance to electric current in physics. The greater the resistance of a conductor, the greater the resistance it provides to electric current. Resistance is a property of the conductor itself and is related to factors such as its size, material, and temperature. The main functions of resistance in circuits include: voltage and current division: In a circuit, resistors can divide voltage and current according to Ohm's law (I=U / R), thereby controlling the voltage and current of each part of the circuit; current limiting protection: series resistors in a circuit can limit the amount of current passing through, preventing components from being damaged by overcurrent and ensuring the safe operation of the circuit; thermal effect: resistors convert electrical energy into heat energy when energized. This characteristic makes resistors a good choice for heating elements and are widely used in household appliances and industrial equipment; impedance matching: in high-frequency circuits or wireless communication systems, the role of matching resistors is to ensure maximum energy transmission and minimum signal reflection, thereby improving transmission efficiency.

[0029] See also Figure 1 Optionally, two pairs of PCS units under test are provided. Each pair of PCS units under test includes two PCS modules under test, the DC sides of the two PCS modules under test are connected, and the connected DC sides are connected to a DC source. Each pair of PCS units under test includes two PCS modules under test, and each pair of PCS units under test is connected to two inductors, with the AC side of one PCS module under test connected to one end of one inductor, the AC side of the other PCS module under test connected to one end of the other inductor, and the other ends of the two inductors connected. The critical coupling point of the two inductors is connected to one side of the transformer.

[0030] Optionally, the AC sides of the PCS module 1 to be tested and the PCS module 2 to be tested are respectively connected in series with an inductor with a larger inductance value and then connected together, and the DC sides of the PCS module 1 to be tested and the PCS module 2 to be tested are directly connected and then connected to a DC power supply. Similarly, the AC sides of the PCS module 3 to be tested and the PCS module 4 to be tested are respectively connected in series with a group of inductors and then connected together, and the DC sides are directly connected and then connected to a common DC source point; a smaller grounding resistor is respectively connected in parallel at the PCC points of the two parallel-connected PCS modules, and then connected to the power grid through a three-winding transformer and an LC filter.

[0031] An investigation into common PCS testing methods currently available on the market revealed that PCS pairing operations currently rely primarily on a one-to-one approach to achieve power exchange and verify module performance parameters. To improve PCS module testing efficiency without sacrificing test reliability, multiple PCS modules are connected in parallel. By connecting series inductors and parallel resistors, various adverse effects caused by the parallel connection of PCS modules are suppressed, enabling two-to-two or even many-to-many pairing testing of PCS modules.

[0032] This embodiment can improve the detection efficiency of PCS modules to a certain extent and realize batch production verification of power modules.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the utility model, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the utility model.

Claims

1. A parallel drag test system for multiple groups of PCS modules, characterized by: The PCS unit to be tested comprises a DC side connected to a DC source, an AC side connected to one end of an inductor, the other end of the inductor connected to one side of a transformer, one end of a resistor connected between the inductor and one side of the transformer, and the other side of the transformer connected to an AC power source.

2. A parallel towing test system for multiple groups of PCS modules according to claim 1, characterized in that: Several pairs of PCS units under test are set up.

3. A parallel towing test system for multiple groups of PCS modules according to claim 2, characterized in that: Each pair of PCS test units includes a plurality of PCS modules to be tested, the DC sides of the plurality of PCS modules to be tested are connected, and the connected DC sides are connected to a DC source.

4. A parallel towing test system for multiple groups of PCS modules according to claim 2, characterized in that: Each pair of PCS units under test includes two PCS modules under test. Each pair of PCS units under test is connected to several inductors, the number of inductors is the same as the number of PCS modules under test. The AC side of each PCS module under test is connected to one end of an inductor and the other ends of several inductors are connected.

5. A parallel drag test system for multiple groups of PCS modules according to claim 4, characterized in that: The critical coupling points of several inductors are connected to one side of the transformer.

6. A parallel towing test system for multiple groups of PCS modules according to claim 1, characterized in that: The transformer adopts a three-winding transformer.

7. A parallel towing test system for multiple groups of PCS modules according to claim 1, characterized in that: A filter is connected between the other side of the transformer and the AC power supply.

8. A parallel-connected drag test system for multiple groups of PCS modules according to claim 7, characterized in that: The filter uses an LC filter.

9. A parallel towing test system for multiple groups of PCS modules according to claim 1, characterized in that: The other end of the resistor is grounded.

10. A parallel towing test system for multiple groups of PCS modules according to claim 1, characterized in that: The AC power source is the grid.

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