Energy storage battery test equipment

Abstract

The invention discloses energy storage battery test equipment, relates to the technical field of power electronics, and solves the problem of lack of test equipment adaptive to an ultrahigh-voltage energy storage battery. The energy storage battery test equipment comprises a double split winding transformer, a DC / DC converter and two voltage type PWM rectifiers. A high-voltage winding of the double-split winding transformer is used for being connected with an external alternating current power supply, and two low-voltage split windings of the double-split winding transformer are respectively connected with the input end of a voltage type PWM rectifier. The output ends of the two voltage type PWM rectifiers are connected in series to form a port, and the port is connected to the input end of the DC / DC converter; the output end of the DC / DC converter is used for being connected with an energy storage battery.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and particularly to a testing device for energy storage batteries. Background Art

[0002] With the development of energy storage technology, the voltage of energy storage batteries has been continuously climbing and has entered the ultra-high voltage level range, and it will still show a significant upward trend in the future (currently it has reached 2000V and will develop towards 2500V in the future). However, there is no testing device on the market that is suitable for such ultra-high voltage energy storage batteries, resulting in the stagnation of performance testing work for such ultra-high voltage energy storage batteries (such as testing the performance of such ultra-high voltage energy storage batteries under fast dynamic switching conditions), making it difficult to advance. Summary of the Invention

[0003] In view of the above problems, this application provides a testing device for energy storage batteries to solve the problem of the lack of testing devices suitable for ultra-high voltage energy storage batteries. The specific solutions are as follows:

[0004] This application provides a testing device for energy storage batteries, including: a dual-split-winding transformer, a DC / DC converter, and two voltage-source PWM rectifiers;

[0005] The high-voltage winding of the dual-split-winding transformer is used to connect to an external AC power supply, and the two low-voltage split windings of the dual-split-winding transformer are respectively connected to the input ends of a voltage-source PWM rectifier;

[0006] The output ends of the two voltage-source PWM rectifiers are connected in series to form a port, and this port is connected to the input end of the DC / DC converter; the output end of the DC / DC converter is used to connect to an energy storage battery.

[0007] In a possible implementation, the DC / DC converter is a flying-capacitor type DC / DC converter.

[0008] In a possible implementation, the voltage-source PWM rectifier is a two-level voltage-source PWM rectifier, and the DC / DC converter is a flying-capacitor type three-level input DC / DC converter;

[0009] Or, the voltage-source PWM rectifier is a three-level voltage-source PWM rectifier, and the DC / DC converter is a flying-capacitor type five-level input DC / DC converter.

[0010] In a possible implementation, the two-level voltage-source PWM rectifier includes: a three-phase circuit structure of U, V, and W, and capacitors C1 and C2;

[0011] The output terminals of the two-level voltage source PWM rectifier have a first terminal and a second terminal; the first end of the capacitor C1 is connected to the first terminal, the second end of the capacitor C1 is connected to the first end of the capacitor C2, and the second end of the capacitor C2 is connected to the second terminal;

[0012] The three-phase circuit structures of U, V, and W are the same;

[0013] Among them, the U-phase circuit structure includes: inductor LA, switching transistors Q1A, Q2A, Q3A, Q4A, Q5A, and Q6A;

[0014] One end of the inductor LA serves as the U-phase input terminal, and the other end of the inductor LA, the output terminal of the switching transistor Q2A, and the input terminal of the switching transistor Q3A are connected;

[0015] The input terminal of the switching transistor Q2A, the output terminal of the switching transistor Q1A, and the input terminal of the switching transistor Q5A are connected;

[0016] The input terminal of the switching transistor Q3A, the output terminal of the switching transistor Q6A, and the input terminal of the switching transistor Q4A are connected;

[0017] The output terminal of the switching transistor Q5A, the input terminal of the switching transistor Q6A, and the second end of the capacitor C1 are connected;

[0018] The input terminal of the switching transistor Q1A is connected to the first end of the capacitor C1;

[0019] The output terminal of the switching transistor Q4A is connected to the second end of the capacitor C2.

[0020] In a possible implementation, the three-level voltage source PWM rectifier is a circuit derived from the two-level voltage source PWM rectifier; the output terminals of the three-level voltage source PWM rectifier further have a third terminal, and the second end of the capacitor C1 is connected to the third terminal.

[0021] In a possible implementation, the flying-capacitor three-level input DC / DC converter includes: switching transistors QD1D, QD2D, QD3D, QD4D, QD5D, QD6D, QD7D, QD8D, capacitors C3, C4, C5, inductor LD1, and inductor LD2;

[0022] The input terminals of the flying-capacitor three-level input DC / DC converter have a first terminal, a second terminal, and a third terminal;

[0023] The input terminal of the switching transistor QD1D is connected to the first terminal;

[0024] The output terminal of the switching transistor QD1D, the input terminal of the switching transistor QD2D, and the first terminal of the capacitor C3 are connected together;

[0025] The output terminal of the switching transistor QD2D, the input terminal of the switching transistor QD3D, and the first terminal of the inductor LD1 are connected together;

[0026] The output terminal of the switching transistor QD3D, the input terminal of the switching transistor QD4D, and the second terminal of the capacitor C3 are connected together;

[0027] The output terminal of the switching transistor QD4D, the input terminal of the switching transistor QD5D, and the second terminal are connected together;

[0028] The output terminal of the switching transistor QD5D, the input terminal of the switching transistor QD6D, and the first terminal of the capacitor C4 are connected together;

[0029] The output terminal of the switching transistor QD6D, the input terminal of the switching transistor QD7D, and the first terminal of the inductor LD2 are connected together;

[0030] The output terminal of the switching transistor QD7D, the input terminal of the switching transistor QD8D, and the second terminal of the capacitor C4 are connected together;

[0031] The output terminal of the switching transistor QD8D is connected to the third terminal;

[0032] The second terminal of the inductor LD1, the first terminal of the capacitor C5, and the positive output terminal of the flying-capacitor three-level input DC / DC converter are connected together;

[0033] The second terminal of the inductor LD2, the second terminal of the capacitor C5, and the negative output terminal of the flying-capacitor three-level input DC / DC converter are connected together.

[0034] In a possible implementation, the flying-capacitor five-level input DC / DC converter is a circuit derived from the flying-capacitor three-level input DC / DC converter; the input terminal of the flying-capacitor five-level input DC / DC converter further has a fourth terminal and a fifth terminal, and the flying-capacitor five-level input DC / DC converter further includes a switching transistor Q9D, a switching transistor Q10D, a switching transistor Q11D, and a switching transistor Q12D;

[0035] The input terminal of the switching transistor Q9D is connected to the first terminal of the capacitor C3;

[0036] The output terminal of the switching transistor Q9D, the input terminal of the switching transistor Q10D, and the fourth terminal are connected together;

[0037] The output terminal of the switching transistor Q10D is connected to the second terminal of the capacitor C3;

[0038] The input terminal of the switching transistor Q11D is connected to the first terminal of the capacitor C4;

[0039] The output terminal of the switching transistor Q11D, the input terminal of the switching transistor Q12D, and the fifth terminal are connected;

[0040] The output terminal of the switching transistor Q12D is connected to the second terminal of the capacitor C4.

[0041] In a possible implementation, the DC / DC converter is replaced by a plurality of DC / DC converters; the input terminals of the DC / DC converters are connected in parallel and then connected to the port; the output terminals of the DC / DC converters are independent of each other and are used to be respectively connected to a plurality of energy storage batteries in one-to-one correspondence.

[0042] In a possible implementation, the DC / DC converter is replaced by a plurality of DC / DC converters; the input terminals of the DC / DC converters are connected in parallel and then connected to the port; the output terminals of the DC / DC converters are connected in parallel to form a port for connecting an energy storage battery.

[0043] In a possible implementation, the dual-split-winding transformer is replaced by two single-winding transformers; the high-voltage windings of the two single-winding transformers are connected in parallel to form a port for connecting an external AC power supply; the low-voltage windings of the two single-winding transformers are respectively connected to the input terminals of a voltage-source PWM rectifier.

[0044] By means of the above technical solution, based on the electrical independence of the two low-voltage split windings, the dual-split-winding transformer provides independent power supplies for the two voltage-source PWM rectifiers respectively; after the output terminals of the two voltage-source PWM rectifiers are connected in series, the output characteristics of the series connection port are equivalent to those of a voltage-source PWM rectifier with more levels (achieving higher-precision voltage control) and a higher voltage output. Thus, without increasing the withstand voltage rating of the switching transistors in a single voltage-source PWM rectifier and without complex adjustment of the control logic of a single voltage-source PWM rectifier, an increase in the number of levels and an increase in the output voltage are achieved, that is, without sacrificing the system performance, the cost and complexity of the system are significantly reduced; after the total voltage after series connection is converted by the DC / DC converter, it provides a voltage input that is precisely adapted to the performance test of the ultra-high-voltage energy storage battery to meet the test requirements. Description of the Drawings

[0045] Combined with the drawings and referring to the following specific embodiments, the above and other features, advantages, and aspects of the various embodiments of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic and the original components and elements are not necessarily drawn to scale.

[0046] Figure 1 It is a schematic structural diagram of an energy storage battery testing device provided by the present application;

[0047] Figure 2 Structural schematic diagram of another energy storage battery testing device provided by this application;

[0048] Figure 3 Circuit topology diagram of a two-level voltage source PWM rectifier provided by this application;

[0049] Figure 4 Circuit topology diagram of a three-level voltage source PWM rectifier provided by this application;

[0050] Figure 5 Circuit topology diagram of a flying capacitor type three-level input DC / DC converter provided by this application;

[0051] Figure 6 Circuit topology diagram of a flying capacitor type five-level input DC / DC converter provided by this application. Specific implementation manners

[0052] In the following elaboration, in order to ensure the accuracy of citation and the fluency of reading, the key technical terms, abbreviations or acronyms involved in the text are summarized and explained as follows:

[0053] DC / DC: Direct Current / Direct Current, direct current / direct current;

[0054] PWM: Pulse Width Modulation, pulse width modulation;

[0055] VSR: Voltage-Source PWM Rectifier, voltage source PWM rectifier;

[0056] VSI: Voltage Source Inverter, voltage source inverter;

[0057] IGBT: Insulated Gate Bipolar Transistor, insulated gate bipolar transistor.

[0058] The embodiment of this application provides an energy storage battery measurement device, filling the market gap of testing devices adapted to ultra-high voltage energy storage batteries, enabling the performance testing work of ultra-high voltage energy storage batteries in complex scenarios such as rapid dynamic switching conditions to be carried out smoothly, and strongly promoting the development and application of ultra-high voltage energy storage battery technology.

[0059] Next, in combination with the accompanying drawings, an energy storage battery measurement device provided by the embodiment of this application will be described in detail. Those of ordinary skill in the art can know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0060] In the description, claims and the above-mentioned drawings of this application, terms such as "first" and "second" are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, which is only a way of distinguishing objects with the same attributes when describing embodiments of this application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, so that a process, method, system, product or device including a series of units does not have to be limited to those units, but may include other units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0061] See Figure 1 , a measurement device for energy storage batteries provided by an embodiment of this application includes: a dual-split winding transformer T1, a DC / DC converter, and two voltage-source PWM rectifiers;

[0062] The high-voltage winding of the dual-split winding transformer T1 is used to connect to an external AC power supply, and the two low-voltage split windings of the dual-split winding transformer T1 are respectively connected to the input ends of a voltage-source PWM rectifier;

[0063] The output ends of the two voltage-source PWM rectifiers are connected in series to form a port, and this port is connected to the input end of the DC / DC converter; the output end of the DC / DC converter is used to connect to the energy storage battery BAT.

[0064] Next, the working principle of the embodiment of this application will be described in detail:

[0065] The dual-split winding transformer T1 has a high-voltage winding and two low-voltage split windings. These two low-voltage split windings are electrically independent of each other, but are magnetically coupled. Specifically, when the dual-split winding transformer T1 operates, its high-voltage winding is connected to an external AC power supply (such as a 220V AC power grid), and its two low-voltage split windings are respectively connected to the input ends of the two voltage-source PWM rectifiers; due to the electrical independence between the two low-voltage split windings, they can respectively provide power for different voltage-source PWM rectifiers; at the same time, since the two low-voltage split windings are magnetically coupled, the electrical energy of the high-voltage winding can be distributed to the two low-voltage split windings in a certain ratio (such as 50:50).

[0066] The voltage-source PWM rectifier is a power electronic device that realizes energy conversion by controlling the output voltage. It usually adopts a VSI structure and adjusts the amplitude and phase of the output voltage through PWM technology, so as to achieve precise control of the input current. The voltage-source PWM rectifier has a fast dynamic response ability and is suitable for application scenarios that require fast voltage regulation.

[0067] After the output terminals of two voltage-source PWM rectifiers are connected in series, the output characteristics of the series connection port are equivalent to those of a voltage-source PWM rectifier with more levels and a higher voltage output. Thus, without increasing the breakdown voltage rating of the switching devices in a single voltage-source PWM rectifier and without complex adjustment of the control logic of a single voltage-source PWM rectifier, an increase in the number of levels and an increase in the output voltage are achieved. After the total voltage after series connection is converted by a DC / DC converter, it provides a precisely adapted ultra-high voltage input for the performance test of ultra-high voltage energy storage batteries to meet the test requirements. The specific analysis is as follows:

[0068] The voltage-source PWM rectifier can adopt a two-level, three-level or more-level topology. The two-level voltage-source PWM rectifier converts the input three-phase AC power of U, V, and W into DC power output by controlling the on / off of the switching devices. There are two voltage states at its output terminal, namely the positive level (+1) and the negative level (-1), as Figure 1 shown. The three-level voltage-source PWM rectifier converts the input three-phase AC power of U, V, and W into DC power output by controlling the on / off of the switching devices. There are three voltage states at its output terminal, namely the positive level (+1), the zero level (0), and the negative level (-1), as Figure 2 shown. These different voltage states are precisely controlled through PWM modulation technology, providing diverse power conversion capabilities for energy storage battery measurement devices to meet the requirements for output voltage level, waveform quality, and system breakdown voltage performance under different application scenarios. The more levels there are at the output terminal of the voltage-source PWM rectifier, the higher the precision of voltage control can be achieved. However, correspondingly, the control algorithm of the voltage-source PWM rectifier will become more complex.

[0069] Still referring to Figure 1 , when a two-level voltage-source PWM rectifier is adopted, the output terminals of two two-level voltage-source PWM rectifiers are connected in series to form a three-level output terminal. There are three voltage states at this three-level output terminal, namely the positive level (+1), the zero level (0), and the negative level (-1), which is equivalent to the output characteristics of a three-level voltage-source PWM rectifier. It can be seen that this series connection method not only increases the number of levels, makes the output voltage regulation more delicate, and improves the precision of voltage control, but also enables the overall circuit to output a higher voltage through voltage superposition. The total voltage after series connection is converted by a DC / DC converter (the DC / DC converter at this time is a three-level input DC / DC converter) so that it can precisely adapt to the ultra-high voltage input requirements for the performance test of ultra-high voltage energy storage batteries.

[0070] Meanwhile, due to the electrical independence of the two two-level voltage source PWM rectifiers, this series connection method does not increase the voltage withstand level of the switching devices in a single two-level voltage source PWM rectifier. Compared with the traditional three-level voltage source PWM rectifier, the selection and design of the switching devices can remain unchanged, without the need to use switching devices with a higher voltage withstand level. Thus, without sacrificing performance, the voltage withstand requirement for the switching devices is reduced.

[0071] Meanwhile, since the control logic of each two-level voltage source PWM rectifier is relatively independent, the control complexity of the overall system does not increase significantly. Compared with the traditional three-level voltage source PWM rectifier, the control logic of the two-level voltage source PWM rectifier is more concise. The control strategy mainly focuses on how to coordinate the outputs of the two two-level voltage source PWM rectifiers so that they can work stably and efficiently after being connected in series, without the need for complex adjustment of the control algorithm of a single two-level voltage source PWM rectifier. Thus, without sacrificing performance, the control logic of the overall system is simplified.

[0072] It can be seen that Figure 1 the series connection method in Figure 1 makes the circuit have the same number of levels and output voltage level as the traditional three-level voltage source PWM rectifier. However, compared with the traditional five-level voltage source PWM rectifier, since

[0073] the two-level voltage source PWM rectifier is used in Figure 2 , its control logic is more concise, and the requirement for the voltage withstand level of the switching devices is also lower. Thus, without sacrificing performance, the cost and complexity of the system are significantly reduced. Figure 2 The series connection method in Figure 2 makes the circuit have the same number of levels and output voltage level as the traditional five-level voltage source PWM rectifier. However, compared with the traditional five-level voltage source PWM rectifier, since Figure 1 the three-level voltage source PWM rectifier is used in Figure 2 the shown embodiment is applicable to the performance test of energy storage batteries with a higher voltage. In Figure 2Among them, after the total voltage after series connection passes through a DC / DC converter (the DC / DC converter at this time is a five-level input DC / DC converter), it is converted to provide a voltage input that is precisely adapted to the energy storage battery with a higher voltage, meeting the test requirements.

[0074] Through experiments, the embodiments of the present application can be used to implement the performance test of energy storage batteries with a voltage level above 2500V, and can be downward compatible to test the performance of energy storage batteries of 2000V. In addition, by further increasing the level number of a single voltage source PWM rectifier, it can also be extended to the performance test of energy storage batteries of 3000V.

[0075] The DC / DC converter in any energy storage battery measurement device provided by the embodiments of the present application can adopt a flying capacitor type DC / DC converter. In the application scenario of traditional DC / DC converters, when the input voltage of the DC / DC converter is too high, the device needs to bear a great withstand voltage pressure, which is not only easy to be damaged, but also the cost of the high withstand voltage device adapted is high. The flying capacitor type DC / DC converter introduces flying capacitors. When the internal switching tubes perform on-off actions, the flying capacitors synchronously participate in the charge and discharge process, and distribute the excessive voltage reasonably to multiple groups of switching tubes and capacitors. This voltage equalization mechanism greatly reduces the voltage borne by a single device, effectively solves the problem of device withstand voltage, enhances the reliability of circuit operation, reduces the dependence on high-cost withstand voltage devices, realizes cost reduction and efficiency improvement, and provides a stable guarantee for the precise voltage conversion required for the performance test of ultra-high voltage energy storage batteries.

[0076] Furthermore, the adaptation relationship between the DC / DC converter and the voltage source PWM rectifier in the energy storage battery measurement device provided by the embodiments of the present application includes: when the voltage source PWM rectifier is a two-level voltage source PWM rectifier, the DC / DC converter is a flying capacitor type three-level input DC / DC converter; when the voltage source PWM rectifier is a three-level voltage source PWM rectifier, the DC / DC converter is a flying capacitor type five-level input DC / DC converter.

[0077] Among them, the two-level voltage source PWM rectifier can adopt the circuit topology structure shown in Figure 3, including: U, V, and W three-phase circuit structures, and capacitors C1 and C2;

[0078] The output end of the two-level voltage source PWM rectifier has two terminals, namely the first terminal and the second terminal. The first terminal is also the positive level (+1) terminal, and the second terminal is also the negative level (-1) terminal; the first end of capacitor C1 is connected to the positive level (+1) terminal of the output end of the two-level voltage source PWM rectifier, the second end of capacitor C1 is connected to the first end of capacitor C2, and the second end of capacitor C2 is connected to the negative level (-1) terminal of the output end of the two-level voltage source PWM rectifier;

[0079] The U, V, and W three-phase circuit structures are the same;

[0080] The U-phase circuit structure includes: inductor LA, switching transistors Q1A, Q2A, Q3A, Q4A, Q5A, and Q6A;

[0081] One end of inductor LA serves as the U-phase input terminal, and the other end of inductor LA, the output terminal of switching transistor Q2A, and the input terminal of switching transistor Q3A are connected;

[0082] The input terminal of switching transistor Q2A, the output terminal of switching transistor Q1A, and the input terminal of switching transistor Q5A are connected;

[0083] The input terminal of switching transistor Q3A, the output terminal of switching transistor Q6A, and the input terminal of switching transistor Q4A are connected;

[0084] The output terminal of switching transistor Q5A, the input terminal of switching transistor Q6A, and the second terminal of capacitor C1 are connected.

[0085] The input terminal of switching transistor Q1A is connected to the first terminal of capacitor C1;

[0086] The output terminal of switching transistor Q4A is connected to the second terminal of capacitor C2.

[0087] The inductor LA, switching transistors Q1A, Q2A, Q3A, Q4A, Q5A, and Q6A in the U-phase circuit structure respectively correspond to the inductor LB, switching transistors Q1B, Q2B, Q3B, Q4B, Q5B, and Q6B in the V-phase circuit structure, and respectively correspond to the inductor LC, switching transistors Q1C, Q2C, Q3C, Q4C, Q5C, and Q6C in the W-phase circuit structure.

[0088] The three-level voltage source PWM rectifier can be a circuit derived from Figure 3 the shown two-level voltage source PWM rectifier; the output terminal of this three-level voltage source PWM rectifier also has a third terminal, namely the zero-level (0) terminal, and the second terminal of capacitor C1 is connected to the zero-level (0) terminal, as Figure 4 shown. Among them, the derived circuit, also known as the derivative circuit, is used to describe a circuit structure obtained by modifying, expanding, or adding certain components based on another circuit structure.

[0089] The flying capacitor type three-level input DC / DC converter can adopt the circuit topology shown in Figure 5, including: switching transistors QD1D, QD2D, QD3D, QD4D, QD5D, QD6D, QD7D, QD8D, capacitor C3, capacitor C4, capacitor C5, inductor LD1 and inductor LD2;

[0090] The input end of the flying capacitor type three-level input DC / DC converter has a first terminal, a second terminal and a third terminal. The first terminal is also the positive level (+1) terminal, the second terminal is also the zero level (0) terminal, and the third terminal is also the negative level (-1) terminal;

[0091] The input end of switching transistor QD1D is connected to the first terminal;

[0092] The output end of switching transistor QD1D, the input end of switching transistor QD2D and the first end of capacitor C3 are connected;

[0093] The output end of switching transistor QD2D, the input end of switching transistor QD3D and the first end of inductor LD1 are connected;

[0094] The output end of switching transistor QD3D, the input end of switching transistor QD4D and the second end of capacitor C3 are connected;

[0095] The output end of switching transistor QD4D, the input end of switching transistor QD5D and the second terminal are connected;

[0096] The output end of switching transistor QD5D, the input end of switching transistor QD6D and the first end of capacitor C4 are connected;

[0097] The output end of switching transistor QD6D, the input end of switching transistor QD7D and the first end of inductor LD2 are connected;

[0098] The output end of switching transistor QD7D, the input end of switching transistor QD8D and the second end of capacitor C4 are connected;

[0099] The output end of switching transistor QD8D is connected to the third terminal;

[0100] The second end of inductor LD1, the first end of capacitor C5 and the output positive terminal (+) of the flying capacitor type three-level input DC / DC converter are connected;

[0101] The second end of inductor LD2, the second end of capacitor C5 and the output negative terminal (-) of the flying capacitor type three-level input DC / DC converter are connected.

[0102] The flying capacitor type five-level input DC / DC converter is based on Figure 5The circuit derived from the flying capacitor type three-level input DC / DC converter shown, as Figure 6 shown, the input end of the flying capacitor type five-level input DC / DC converter also has a fourth terminal and a fifth terminal (at this time, the first terminal and the third terminal at the input end of the flying capacitor type three-level input DC / DC converter become the positive high voltage level (+2) terminal and the negative high voltage level (-2) of the flying capacitor type five-level input DC / DC converter respectively, and the fourth terminal and the fifth terminal are the positive low voltage level (+1) terminal and the negative low voltage level (-1) respectively), and the flying capacitor type five-level input DC / DC converter also includes a switching tube Q9D, a switching tube Q10D, a switching tube Q11D, and a switching tube Q12D;

[0103] The input end of the switching tube Q9D is connected to the first end of the capacitor C3;

[0104] The output end of the switching tube Q9D, the input end of the switching tube Q10D, and the fourth terminal are connected;

[0105] The output end of the switching tube Q10D is connected to the second end of the capacitor C3;

[0106] The input end of the switching tube Q11D is connected to the first end of the capacitor C4;

[0107] The output end of the switching tube Q11D, the input end of the switching tube Q12D, and the fifth terminal are connected;

[0108] The output end of the switching tube Q12D is connected to the second end of the capacitor C4.

[0109] Figures 3 to 6 The switching tubes in [[ ]] are usually IGBTs. The input end of the switching tube is the collector of the IGBT, and the output end of the switching tube is the emitter of the IGBT.

[0110] In addition, to facilitate batch testing of multiple energy storage batteries, the DC / DC converter in any of the above-provided energy storage battery testing devices can be replaced by multiple DC / DC converters; the input ends of the DC / DC converters are connected in parallel and then connected to the port; the output ends of the DC / DC converters are independent of each other and are used to be respectively connected to multiple energy storage batteries one by one. The specific analysis is as follows:

[0111] Because the input ends of the DC / DC converters are connected in parallel, the electric energy from the same power source can be distributed to multiple DC / DC conversion circuits, and each DC / DC converter can independently test an energy storage battery, thereby improving the test efficiency.

[0112] In addition, when this method is adopted for a large-rated current energy storage battery, the DC / DC converter in any of the above-provided energy storage battery test devices can be replaced by multiple DC / DC converters; the input ends of the DC / DC converters are connected in parallel and then connected to the port; the output ends of the DC / DC converters are connected in parallel to form a port for connecting the energy storage battery. The specific analysis is as follows:

[0113] The parallel connection of the input ends of the DC / DC converters is still for obtaining electrical energy from the same power source, and the parallel connection of the output ends can superimpose the output currents of multiple DC / DC conversion circuits, so as to provide sufficient charging or discharging current for the energy storage battery with a large-rated current. Multiple DC / DC converters share the large current together to meet the test requirements of the large-current energy storage battery, avoiding excessive current load on a single DC / DC converter, which is beneficial to improving the reliability and stability of the system.

[0114] In addition, the double-split-winding transformer can be replaced by two single-winding transformers; the high-voltage windings of the two single-winding transformers are connected in parallel to form a port for connecting an external AC power source; the low-voltage windings of the two single-winding transformers are respectively connected to the input ends of a voltage-source PWM rectifier. The specific analysis is as follows:

[0115] The advantage of this replacement method is that it significantly reduces the design and manufacturing difficulty. The structure of a single transformer is simple, the winding connection is flexible, which is convenient for subsequent maintenance and replacement. However, after the combination of two single-winding transformers, the volume and weight increase significantly, occupying more space, and the power transmission efficiency and electromagnetic coupling performance may be inferior to those of the double-split-winding transformer. In practical applications, by comprehensively considering factors such as space limitations, cost budgets, and performance indicators, the type of transformer can be reasonably selected.

[0116] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present application. Therefore, the embodiments of the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A storage battery testing device, characterized in that, Including: A dual-split-winding transformer, a DC / DC converter, and two voltage-source PWM rectifiers; The high-voltage winding of the dual-split-winding transformer is used to connect to an external AC power supply, and the two low-voltage split windings of the dual-split-winding transformer are respectively connected to the input ends of a voltage-source PWM rectifier; The output ends of the two voltage-source PWM rectifiers are connected in series to form a port, and this port is connected to the input end of the DC / DC converter; the output end of the DC / DC converter is used to connect to an energy storage battery.

2. The energy storage battery testing device according to claim 1, wherein The DC / DC converter is a flying-capacitor type DC / DC converter.

3. The energy storage battery testing device according to claim 1, wherein The voltage-source PWM rectifier is a two-level voltage-source PWM rectifier, and the DC / DC converter is a flying-capacitor type three-level input DC / DC converter; Or, the voltage-source PWM rectifier is a three-level voltage-source PWM rectifier, and the DC / DC converter is a flying-capacitor type five-level input DC / DC converter.

4. The energy storage battery testing device according to claim 3, characterized in that The two-level voltage-source PWM rectifier includes: a three-phase circuit structure of U, V, and W, and capacitors C1 and C2; The output end of the two-level voltage-source PWM rectifier has a first terminal and a second terminal; the first end of capacitor C1 is connected to the first terminal, the second end of capacitor C1 is connected to the first end of capacitor C2, and the second end of capacitor C2 is connected to the second terminal; The three-phase circuit structures of U, V, and W are the same; Among them, the U-phase circuit structure includes: inductor LA, switching tubes Q1A, Q2A, Q3A, Q4A, Q5A, and Q6A; One end of inductor LA serves as the U-phase input end, and the other end of inductor LA, the output end of switching tube Q2A, and the input end of switching tube Q3A are connected; The input end of switching tube Q2A, the output end of switching tube Q1A, and the input end of switching tube Q5A are connected; The input end of switching tube Q3A, the output end of switching tube Q6A, and the input end of switching tube Q4A are connected; The output end of switching tube Q5A, the input end of switching tube Q6A, and the second end of capacitor C1 are connected; The input end of switching tube Q1A is connected to the first end of capacitor C1; The output end of switching tube Q4A is connected to the second end of capacitor C2.

5. The energy storage battery testing device according to claim 4, wherein, The three-level voltage-source PWM rectifier is a circuit derived from the two-level voltage-source PWM rectifier; the output end of the three-level voltage-source PWM rectifier also has a third terminal, and the second end of capacitor C1 is connected to the third terminal.

6. The energy storage battery testing device according to claim 3, wherein, The flying-capacitor type three-level input DC / DC converter includes: switching tubes QD1D, QD2D, QD3D, QD4D, QD5D, QD6D, QD7D, QD8D, capacitors C3, C4, C5, inductor LD1, and inductor LD2; The input end of the flying-capacitor type three-level input DC / DC converter has a first terminal, a second terminal, and a third terminal; The input end of switching tube QD1D is connected to the first terminal; The output end of switching tube QD1D, the input end of switching tube QD2D, and the first end of capacitor C3 are connected; The output terminal of the switching transistor QD2D, the input terminal of the switching transistor QD3D, and the first terminal of the inductor LD1 are connected together; The output terminal of the switching transistor QD3D, the input terminal of the switching transistor QD4D, and the second terminal of the capacitor C3 are connected together; The output terminal of the switching transistor QD4D, the input terminal of the switching transistor QD5D, and the second terminal are connected together; The output terminal of the switching transistor QD5D, the input terminal of the switching transistor QD6D, and the first terminal of the capacitor C4 are connected together; The output terminal of the switching transistor QD6D, the input terminal of the switching transistor QD7D, and the first terminal of the inductor LD2 are connected together; The output terminal of the switching transistor QD7D, the input terminal of the switching transistor QD8D, and the second terminal of the capacitor C4 are connected together; The output terminal of the switching transistor QD8D is connected to the third terminal; The second terminal of the inductor LD1, the first terminal of the capacitor C5, and the positive output terminal of the flying-capacitor three-level input DC / DC converter are connected together; The second terminal of the inductor LD2, the second terminal of the capacitor C5, and the negative output terminal of the flying-capacitor three-level input DC / DC converter are connected together.

7. The energy storage battery testing device according to claim 6, characterized in that The flying-capacitor five-level input DC / DC converter is a circuit derived from the flying-capacitor three-level input DC / DC converter; the input terminal of the flying-capacitor five-level input DC / DC converter further includes a fourth terminal and a fifth terminal, and the flying-capacitor five-level input DC / DC converter further includes switching transistors Q9D, Q10D, Q11D, and Q12D; The input terminal of the switching transistor Q9D is connected to the first terminal of the capacitor C3; The output terminal of the switching transistor Q9D, the input terminal of the switching transistor Q10D, and the fourth terminal are connected together; The output terminal of the switching transistor Q10D is connected to the second terminal of the capacitor C3; The input terminal of the switching transistor Q11D is connected to the first terminal of the capacitor C4; The output terminal of the switching transistor Q11D, the input terminal of the switching transistor Q12D, and the fifth terminal are connected together; The output terminal of the switching transistor Q12D is connected to the second terminal of the capacitor C4.

8. The energy storage battery testing device according to any one of claims 1 to 7, characterized in that The DC / DC converter is replaced by a plurality of DC / DC converters; the input terminals of the DC / DC converters are connected in parallel and then connected to the port; the output terminals of the DC / DC converters are independent of each other and are used to be respectively connected to a plurality of energy storage batteries in one-to-one correspondence.

9. The energy storage battery testing device according to any one of claims 1 to 7, characterized in that, The DC / DC converter is replaced by a plurality of DC / DC converters; the input terminals of the DC / DC converters are connected in parallel and then connected to the port; the output terminals of the DC / DC converters are connected in parallel to form a port for connecting to an energy storage battery.

10. The energy storage battery testing device according to any one of claims 1 to 7, characterized in that The dual-split-winding transformer is replaced by two single-winding transformers; the high-voltage windings of the two single-winding transformers are connected in parallel to form a port for connecting to an external AC power supply; the low-voltage windings of the two single-winding transformers are respectively connected to the input terminals of a voltage-type PWM rectifier.

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