Testing device of energy storage converter

Abstract

The utility model provides a testing device for an energy storage converter. The testing device comprises a first switch connected to a power grid; the low-voltage end of the first transformer is connected with the first switch; the alternating-current power grid simulation unit is connected with the high-voltage end of the first transformer; the second switch is connected with the second end of the AC power grid simulation unit. The low-voltage end of the second transformer is connected with the second switch; the third switch is connected with the high-voltage end of the second transformer; and each test branch is connected between the first end of the second switch and the second end of the third switch. The second switch, the third switch and the test branch form a test loop, so that energy circulation is realized, the test efficiency can be improved to the maximum extent, and the energy consumption can be reduced; the alternating-current power grid simulation unit simulates an alternating-current power supply output by a power grid, parallel operation testing of a plurality of tested energy storage converters is achieved, parallel operation synchronization performance, electrical performance, control and response performance, thermal performance and protection performance can be fully verified, and wide applicability is achieved.

Description

Technical Field

[0001] This application relates to the field of power energy storage technology, and in particular to a testing device for an energy storage converter. Background Technology

[0002] Power conversion systems (PCS) have become an indispensable core component for power conversion in energy storage systems, and their stability and reliability directly affect the operating efficiency of the entire system. Especially in the field of string PCS, its compact size, flexible deployment capabilities, and convenient maintenance have made it a crucial component in various types of energy storage systems, demonstrating broad application prospects. However, with the continuous iteration and upgrading of string PCS technology, its testing requirements are becoming increasingly complex and diverse. Therefore, designing and developing an efficient and economical energy storage PCS testing platform has become a critical issue that urgently needs to be addressed in the current energy storage technology field.

[0003] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Utility Model Content

[0004] This application aims to at least partially address one of the technical problems in the related art.

[0005] Therefore, one objective of this application is to provide a testing device for an energy storage converter, comprising: an AC power grid simulation unit, a first transformer, a second transformer, a first switch, a second switch, a third switch, and at least one test branch, wherein: a first terminal of the first switch is connected to the power grid; a low-voltage terminal of the first transformer is connected to a second terminal of the first switch; a first terminal of the AC power grid simulation unit is connected to a high-voltage terminal of the first transformer for simulating AC power output from the power grid; a first terminal of the second switch is connected to a second terminal of the AC power grid simulation unit; a low-voltage terminal of the second transformer is connected to a second terminal of the second switch; a first terminal of the third switch is connected to a high-voltage terminal of the second transformer; and each of the test branches is connected between the first terminal of the second switch and the second terminal of the third switch.

[0006] Each of the test branches is connected to a test energy storage converter; when the first switch, the second switch and the third switch are all closed, the test energy storage converter is subjected to electrical performance testing, control and response testing, thermal performance testing and protection performance testing through the AC power output of the AC power grid simulation unit.

[0007] According to a test apparatus for an energy storage converter according to an embodiment of this application, the first switch, the second switch and the third switch all include a circuit breaker and a leakage current protection switch.

[0008] According to one embodiment of the present application, the test apparatus for an energy storage converter includes an AC grid simulation unit with operating modes including grid-connected mode and off-grid mode.

[0009] According to one embodiment of the present application, the test apparatus for an energy storage converter includes an AC power grid simulation unit comprising a four-quadrant frequency converter.

[0010] According to an embodiment of the present application, the test apparatus for an energy storage converter includes an AC grid simulation unit that further comprises a rectifier bridge, a DC-DC converter, and an inverter. The first end of the rectifier bridge is connected to the high-voltage end of the first transformer; the first end of the DC-DC converter is connected to the second end of the rectifier bridge; and the inverter is connected to the second end of the DC-DC converter.

[0011] According to one embodiment of the present application, the test apparatus for an energy storage converter includes a DC-DC converter of the following types: buck, boost, and buck-boost.

[0012] According to an embodiment of the energy storage converter testing apparatus of this application, the AC power grid simulation unit further includes a multi-winding transformer unit, at least one power unit, at least one control unit, a transmission unit, and a communication unit. The multi-winding transformer unit is connected to the high-voltage end of the first transformer to provide multiple output voltage levels. Each power unit is connected to the multi-winding transformer unit to simulate power flow and conversion in the power grid, wherein the number of power units is equal to the number of output voltage levels. Each control unit is connected to the corresponding power unit to control the frequency, amplitude fluctuations, harmonics, flicker, and balance characteristics of the simulated power grid, wherein the number of control units is equal to the number of power units. The transmission unit is connected to each control unit to output and simulate AC power supply. The communication unit is connected to each control unit to externally connect the simulated AC power supply characteristic parameters to an analysis device.

[0013] According to a test apparatus for an energy storage converter according to an embodiment of this application, both the first transformer and the second transformer are isolation transformers.

[0014] According to an embodiment of the present application, a test apparatus for an energy storage converter includes a test branch comprising a test switch, a test structure, and an AC-DC dual power supply. The test switch is connected to a first terminal of a second switch; the test structure is connected to the test switch and is used to connect to the energy storage converter under test; the AC-DC dual power supply is connected between the test structure and a second terminal of a third switch.

[0015] According to one embodiment of the present application, the ratio of the capacity of the AC-DC dual power supply to the rated capacity of the energy storage converter under test is greater than 1.2.

[0016] In this application, a test loop is formed by the second switch, the third switch, and the test branch to achieve energy circulation, which can maximize test efficiency and reduce energy consumption. The AC power supply output by the AC power grid is simulated by the AC power grid simulation unit to realize the parallel testing of multiple energy storage converters under test. This can fully verify the parallel synchronization performance, electrical performance, control and response performance, thermal performance, and protection performance, and has wide applicability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a test device for an energy storage converter according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the structure of an AC power grid simulation unit according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of another AC power grid simulation unit according to an embodiment of this application. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0021] The embodiments of this application will now be described with reference to the accompanying drawings.

[0022] Figure 1 This is a schematic diagram of the structure of a test device for an energy storage converter according to an embodiment of this application, as shown below. Figure 1 As shown, the testing apparatus for the energy storage converter in this embodiment includes an AC grid simulation unit, a first transformer, a second transformer, a first switch, a second switch, a third switch, and at least one test branch, wherein:

[0023] The first terminal of the first switch is connected to the power grid, used to distribute electrical energy from the grid to specific loads. The grid voltage levels include 380V and 690V. The low-voltage terminal of the first transformer is connected to the second terminal of the first switch, used to convert electrical energy from one voltage level to another. The first terminal of the AC power grid simulation unit is connected to the high-voltage terminal of the first transformer, used to simulate the operating states and interrelationships of various components in the power system, including simulating the AC power output from the grid (with 380V and 690V voltage regulation), the grid supplying power to the device under test (DUT), and the grid absorbing DUT's grid-connected power. It can also controllably simulate various anomalies in actual grid operation, such as grid harmonics and three-phase imbalance. The first terminal of the second switch is connected to the second terminal of the AC power grid simulation unit, controlling the connection status between the AC power grid simulation unit and subsequent circuits or loads. The low-voltage terminal of the second transformer is connected to the second terminal of the second switch, used to convert the output of the AC power grid simulation unit to the voltage level required by the test branch. The first terminal of the third switch is connected to the high-voltage terminal of the second transformer, used to transmit electrical energy to the test branch. Each test branch is connected between the first terminal of the second switch and the second terminal of the third switch. Each test branch connects to a single energy storage converter under test (DUT). When the first, second, and third switches are all closed, the DUT is tested for electrical performance, control and response, thermal performance, and protection performance using AC power output from the AC grid simulation unit. It should be noted that the DUT, connected to the test branch, converts electrical energy from one form to another and stores or releases energy. During electrical function testing, the test data includes input / output voltage, current, and power factor to ensure the DUT meets the relevant requirements. During control and response testing, the test data includes the DUT's response speed, accuracy, and stability under different operating conditions, thereby verifying the effectiveness of the DUT's control strategy and algorithm. During thermal performance testing, the test data includes the temperature distribution and heat dissipation performance of the DUT under long-term operation or high load conditions to ensure safe operation. When conducting protection performance tests, the test content includes whether the protection mechanism of the tested energy storage converter is effective under abnormal operating conditions such as overcurrent, overvoltage, and undervoltage, so as to ensure that the tested energy storage converter can quickly disconnect the circuit under fault conditions to prevent equipment damage or safety accidents.

[0024] Optionally, as an example, such as Figure 1As shown, the first, second, and third switches all include circuit breakers and residual current devices (RCDs). It should be noted that the first, second, and third switches can have overload protection functions. When the current in the circuit exceeds the rated value, the first, second, and third switches will automatically cut off the power transmission to prevent damage to wires and equipment due to overheating, or even to prevent fires. In the event of a short circuit, the first, second, and third switches will automatically cut off the power transmission to prevent damage to the circuit and equipment caused by the short-circuit current. It should be added that the configuration of the first, second, and third switches should be selected according to the specific application scenario.

[0025] Optionally, as an example, such as Figure 1 As shown, the AC grid simulation unit operates in two modes: grid-connected and off-grid. In grid-connected mode, the AC grid simulation unit is connected to the actual power grid, jointly providing power to the test branch. The AC grid simulation unit can achieve bidirectional energy flow with the power grid, both supplying and absorbing power from it. In off-grid mode, the AC grid simulation unit disconnects from the power grid and independently provides power to the test branch. Specifically, in the event of a grid failure, the off-grid AC grid simulation unit can independently provide standard-compliant AC power to the test branch. In the event of a sudden power outage, the off-grid AC grid simulation unit can quickly switch to emergency power supply mode to ensure uninterrupted operation of the test branch.

[0026] Optionally, as an example, such as Figure 1 As shown, the AC power grid simulation unit includes a four-quadrant frequency converter. When testing energy storage frequency converters, the main focus is on the performance and response of the energy storage converter under four-quadrant power control. Based on the rated power of the energy storage converter under test and the testing requirements, the four-quadrant frequency converter outputs a power control command. This power control command is in four-quadrant mode, including the first quadrant (positive active power, positive reactive power), the second quadrant (negative active power, positive reactive power), the third quadrant (negative active power, negative reactive power), and the fourth quadrant (positive active power, negative reactive power). The power control command for each quadrant can be generated using discrete quantity calculation formulas and power control command hold formulas. The tested energy storage converter performs energy conversion and bidirectional flow according to the power control command, and generates a response signal, which includes parameters such as active power, reactive power, voltage, and current. By comparing the power control command and the response signal, the performance and response of the tested energy storage converter under four-quadrant power control are analyzed to check whether the tested energy storage converter can accurately and quickly respond to the power control command and realize bidirectional energy flow. The efficiency, stability, reliability and other performance indicators of the tested energy storage converter are evaluated.

[0027] Alternatively, as an example, Figure 2This is a schematic diagram of the structure of an AC power grid simulation unit according to an embodiment of this application. Figure 2 As shown, the AC power grid simulation unit also includes a rectifier bridge, a DC-DC converter, and an inverter. The first terminal of the rectifier bridge is connected to the high-voltage terminal of the first transformer, converting AC to DC. The first terminal of the DC-DC converter is connected to the second terminal of the rectifier bridge, converting the DC power supply to DC (or near-DC) power supplies of different voltages. The inverter is connected to the second terminal of the DC-DC converter, converting the DC power to AC. The AC power output from the inverter is used to perform electrical performance tests, control and response tests, thermal performance tests, and protection performance tests on the energy storage converter. It should be noted that the DC-DC converters include buck, boost, and buck-boost types; the type should be selected according to specific requirements.

[0028] Alternatively, as an example, Figure 3 This is a schematic diagram of another AC power grid simulation unit according to an embodiment of this application. Figure 3 As shown, the AC power grid simulation unit also includes a multi-winding transformer unit, at least one power unit, at least one control unit, a transmission unit, and a communication unit. The multi-winding transformer unit is connected to the high-voltage end of the first transformer. In the simulated power grid, the multi-winding transformer unit can simulate power grid environments at different voltage levels, providing the required voltage input to the subsequent power unit and control unit. Each power unit is connected to the multi-winding transformer unit. In the simulated power grid, the power unit can simulate power flow, conversion, and faults in the power grid, providing real-time power data to the control unit. The number of power units equals the number of output voltage levels. Each control unit is connected to its corresponding power unit and is used to control the frequency and amplitude waveform of the simulated power grid. The simulation includes dynamic, harmonic, flicker, and balance characteristics. Specifically, in the simulated power grid, the control unit can precisely control and adjust the power units according to preset simulation parameters and real-time data to achieve various characteristics of the simulated power grid. The number of control units is equal to the number of power units. The transmission unit is connected to each control unit. In the simulated power grid, the transmission unit can convert the analog signals generated by the control unit into actual AC power output for use by subsequent testing and analysis equipment. The communication unit is connected to each control unit. In the simulated power grid, the communication unit can transmit the simulated AC power characteristic parameters (such as voltage, current, frequency, harmonics, etc.) to external analysis equipment or monitoring systems in real time for further analysis and processing.

[0029] It should be further noted that the AC power grid simulation unit can also be configured using Application Specific Integrated Circuits (ASICs, which are integrated circuits designed and manufactured for specific user requirements and systems; in this embodiment, the integrated circuit is characterized as a stability detection circuit), IP cores (intelligent property cores, which are mature designs of circuit modules with independent functions in chip or integrated circuit designs; these circuit designs can be applied to other chip or integrated circuit design projects that include the circuit module, thereby reducing the design workload, shortening the design cycle, and improving the success rate of chip or integrated circuit design; IP cores are classified into three levels: behavioral, structural, and physical, thus corresponding to three types of IP cores: soft cores designed with hardware description languages, solid cores that complete structural descriptions, and hard cores based on physical descriptions and verified by the process), etc. The specific configuration methods will not be elaborated here; any configuration method of the AC power grid simulation unit can be used as long as it can simulate the AC power output of the power grid, and is not limited to this embodiment.

[0030] Optionally, as an example, such as Figure 1 As shown, both the first and second transformers are isolation transformers. It should be noted that the input and output windings of an isolation transformer are electrically completely isolated. This isolation not only ensures electrical safety between the power supply and the load but also avoids interference and noise caused by grounding issues. The turns ratio of an isolation transformer is typically 1:1, meaning the input voltage is equal to the output voltage, but it can also be designed as a step-up or step-down transformer as needed.

[0031] Optionally, as an example, such as Figure 1As shown, the test branch includes a test switch, a test structure, and an AC-DC dual power supply. The test switch is connected to the first terminal of the second switch. The test switch supports hot-swapping, thereby improving the reliability of the test device. Hot-swapping allows for replacement and maintenance without interruption of power supply, simplifying the maintenance process and reducing maintenance costs. The test structure is connected to the test switch and is used to connect to the energy storage converter under test. The AC-DC dual power supply is connected between the test structure and the second terminal of the third switch. Furthermore, the ratio of the capacity of the AC-DC dual power supply to the rated capacity of the energy storage converter under test is greater than 1.2. It should be noted that the AC-DC dual power supply can be 1.5 times or even more than the rated capacity of the energy storage converter under test, and the AC-DC dual power supply can support voltage levels above 1500V. Considering the integrity of the test of the energy storage converter under test, the communication section of the AC-DC dual power supply can also support the communication protocol of the Battery Management System (BMS) and dry contact configuration output (usually used to provide switching or signal transmission functions between circuits).

[0032] In summary, the testing device for the energy storage converter of this application forms a test loop through the second switch, the third switch, and the test branch, thereby realizing energy circulation, which can maximize testing efficiency and reduce energy consumption. The AC power supply output by the AC power grid is simulated by the AC power grid simulation unit to realize the parallel testing of multiple energy storage converters under test, which can fully verify the parallel synchronization performance, electrical performance, control and response performance, thermal performance and protection performance, and has wide applicability.

[0033] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0036] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A test apparatus for an energy storage converter, characterized by, The application relates to an alternating current power grid simulation unit, a first transformer, a second transformer, a first switch, a second switch, a third switch and at least one test branch, wherein the first end of the first switch is connected to a power grid; the low-voltage end of the first transformer is connected to the second end of the first switch; the first end of the alternating current power grid simulation unit is connected to the high-voltage end of the first transformer, and the alternating current power grid simulation unit is used for simulating an alternating current power supply output by the power grid; the first end of the second switch is connected to the second end of the alternating current power grid simulation unit; the low-voltage end of the second transformer is connected to the second end of the second switch; the first end of the third switch is connected to the high-voltage end of the second transformer; and each test branch is connected between the first end of the second switch and the second end of the third switch. When the first switch, the second switch and the third switch are all closed, the alternating current power supply output by the alternating current power grid simulation unit is used for performing electrical performance testing, control and response testing, thermal performance testing and protection performance testing on the tested energy storage converter. The first switch, the second switch and the third switch all comprise a circuit breaker and a residual current protection switch.

2. The test device of claim 1, wherein, The operation mode of the alternating current power grid simulation unit comprises a grid-connected mode and an off-grid mode.

3. The test device of claim 1, wherein, The alternating current power grid simulation unit comprises a four-quadrant frequency converter.

4. The test device of claim 1 or 3, wherein, The alternating current power grid simulation unit further comprises a rectifier bridge, a DC-DC converter and an inverter, wherein the first end of the rectifier bridge is connected to the high-voltage end of the first transformer; the first end of the DC-DC converter is connected to the second end of the rectifier bridge; and the inverter is connected to the second end of the DC-DC converter.

5. The test device of claim 1 or 3, wherein, The type of the DC-DC converter comprises a step-down type, a step-up type and a step-up / down type.

6. The test device of claim 5, wherein, The alternating current power grid simulation unit further comprises a multi-winding transformer unit, at least one power unit, at least one control unit, a transmission unit and a communication unit, wherein the multi-winding transformer unit is connected to the high-voltage end of the first transformer and is used for providing multiple output voltage levels; each power unit is connected to the multi-winding transformer unit and is used for simulating power flow and conversion in the power grid, wherein the number of the power units is equal to the number of the output voltage levels; each control unit is connected to a corresponding power unit and is used for controlling frequency, amplitude fluctuation, harmonics, flicker and balance characteristics of the simulated power grid, wherein the number of the control units is equal to the number of the power units; the transmission unit is connected to each control unit and is used for outputting and simulating the alternating current power supply; and the communication unit is connected to each control unit and is used for externally connecting characteristic parameters of the simulated alternating current power supply to an analysis device.

7. The test device of claim 1 or 3, wherein, The first transformer and the second transformer are both isolation transformers.

8. The test device of claim 1, wherein, ​ 9. The test device of claim 8, wherein, The test branch comprises a test switch, a test structure and an AC-DC dual power supply, wherein the test switch is connected with the first end of the second switch; the test structure is connected with the test switch and used for accessing the measured energy storage converter; and the AC-DC dual power supply is connected between the test structure and the second end of the third switch.

10. The test device of claim 9, wherein, The ratio of the capacity of the AC-DC dual power supply to the rated capacity of the measured energy storage converter is greater than 1.2.

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