A high-power high-frequency modular battery cluster charge and discharge test device and method

Abstract

The present invention provides a high-power high-frequency modular battery cluster charge and discharge test device, characterized in that the device includes an AC cooperation controller connected to a middle computer, for receiving instructions transmitted by the middle computer and distributing current to a plurality of isolated ACDC modules; a plurality of isolated ACDC modules, the input ends of the plurality of isolated ACDC modules are connected in parallel and then connected to the AC cooperation controller and a three-phase mains power supply, and the output ends are connected in parallel to form a DC bus, for converting alternating current into direct current and achieving voltage isolation; a plurality of BUCK-BOOST modules, the input ends of the plurality of BUCK-BOOST modules are connected in parallel and then connected to the DC bus, and the output ends of the plurality of BUCK-BOOST modules are connected in parallel to a target battery cluster, for testing the charge and discharge of the target battery cluster. The present invention realizes modular design, has high-efficiency charge and discharge capabilities, overcomes the deficiencies of the traditional scheme such as large volume, high cost, and slow dynamic response, improves the efficiency and flexibility of the device, and is applicable to high-power scenarios.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular, to a high-power high-frequency modular battery cluster charge and discharge test device and method. Background Art

[0002] With the rapid development of lithium-ion battery technology, electrochemical energy storage technology has been widely used in multiple fields due to its advantages of high energy density, long life, and high efficiency. In the research and development, production, testing, and other links of lithium-ion batteries, charge and discharge test equipment plays an indispensable role as a key tool. With the continuous progress of technology and the rapid growth of industry demands, higher requirements have been put forward for the technical indicators of battery charge and discharge test equipment, such as supporting higher voltage levels, larger power ranges, higher test accuracies, and faster dynamic response speeds. These demands pose great challenges to traditional test equipment solutions.

[0003] Currently, the mainstream battery cluster charge and discharge test equipment on the market usually adopts a technical solution that combines a power frequency transformer, a high-power ACDC bidirectional converter, and a BUCK-BOOST DCDC bidirectional converter. The power frequency transformer provides necessary voltage conversion and safety isolation for the circuit; the high-power ACDC bidirectional converter is used to realize the energy exchange between the power grid and the DC bus; and the BUCK-BOOST DCDC bidirectional converter is used to realize the voltage regulation and energy control between the DC bus and the battery cluster under test. However, this solution has significant deficiencies in practical applications. For example, the power frequency transformer is large in volume, heavy in weight, and high in noise; the ACDC bidirectional converter has a low switching frequency, resulting in high noise, a large number of devices, a large volume, and high costs; the BUCK-BOOST DCDC converter has a slow dynamic response speed. In addition, the test equipment of this solution needs to be redesigned when parameters change, with high customization costs, long production cycles, and complex after-sales maintenance, making it difficult to meet the urgent needs of the new energy vehicle and energy storage industries for high-performance charge and discharge test equipment. Summary of the Invention

[0004] In view of this, the present invention is committed to providing a high-power high-frequency modular battery cluster charge and discharge test device and method, which are used to solve the problems of large equipment volume, high weight, insufficient dynamic response performance, high production costs, and high difficulty in customized design and maintenance in the prior art.

[0005] In a first aspect, the present invention provides a high-power high-frequency modular battery cluster charge and discharge test device, which includes:

[0006] An AC co-controller, connected to the middle computer, for receiving instructions transmitted by the middle computer and distributing current to a plurality of isolated ACDC modules;

[0007] Multiple isolated AC-DC modules, the input ends of the multiple isolated AC-DC modules are connected in parallel and then connected to the AC co-controller and the three-phase mains power supply, and the output ends are connected in parallel to form a DC bus, which is used to convert alternating current into direct current and achieve voltage isolation;

[0008] Multiple BUCK-BOOST modules, the input ends of the multiple BUCK-BOOST modules are connected in parallel and then connected to the DC bus, and the output ends of the multiple BUCK-BOOST modules are connected in parallel to the target battery cluster, which is used to test the charge and discharge of the target battery cluster.

[0009] Optionally, each isolated AC-DC module includes:

[0010] A three-phase DNPC topology unit, including a first capacitor C1, a second capacitor C2, a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, a first inductor L1, a first diode D1 and a second diode D2;

[0011] The first switch Q1, the second switch Q2, the third switch Q3 and the fourth switch Q4 are connected in series, the collector of the first switch Q1 is connected to the positive pole of the power supply, and the emitter of the fourth switch Q4 is connected to the negative pole of the power supply;

[0012] One end of the first capacitor is connected to the collector of the first switch Q1, and the other end is connected to the B-phase mains input and the C-phase mains input;

[0013] One end of the first inductor L1 is connected between the emitter of the second switch Q2 and the collector of the third switch Q3, and the other end is connected to the A-phase mains input;

[0014] The cathode of the first diode D1 is connected between the emitter of the first switch Q1 and the collector of the second switch Q2, and the anode of the first diode D1 is grounded; the anode of the second diode D2 is connected between the emitter of the third switch Q3 and the collector of the fourth switch Q4, and the cathode of the second diode D2 is grounded;

[0015] One end of the second capacitor C2 is connected to the A-phase mains input, and the other end is grounded.

[0016] Optionally, each isolated AC-DC module further includes:

[0017] An LLC isolated DC-DC unit, including a transformer T1, a third capacitor C3, a fourth capacitor C4, a fifth switch Q5, a sixth switch Q6, a seventh switch Q7, an eighth switch Q8, a ninth switch Q9, a tenth switch Q10, an eleventh switch Q11 and a twelfth switch Q12;

[0018] The fifth switching transistor Q5 and the sixth switching transistor Q6 are connected in series. The drain of the fifth switching transistor Q5 is connected to the positive power supply terminal, and the source of the sixth switching transistor Q6 is connected to the negative power supply terminal; The seventh switching transistor Q7 and the eighth switching transistor Q8 are connected in series. The drain of the seventh switching transistor Q7 is connected to the positive power supply terminal, and the source of the eighth switching transistor Q8 is connected to the negative power supply terminal;

[0019] The ninth switching transistor Q9 and the tenth switching transistor Q10 are connected in series. The drain of the ninth switching transistor Q9 is connected to the positive terminal of the DC bus, and the source of the tenth switching transistor Q10 is connected to the negative terminal of the DC bus; The eleventh switching transistor Q11 and the twelfth switching transistor Q12 are connected in series. The drain of the eleventh switching transistor Q11 is connected to the positive terminal of the DC bus, and the source of the twelfth switching transistor Q12 is connected to the negative terminal of the DC bus; One end of the fourth capacitor is connected to the positive terminal of the DC bus, and the other end is connected to the negative terminal of the DC bus;

[0020] The first port of the transformer T1 is connected between the source of the fifth switching transistor Q5 and the drain of the sixth switching transistor Q6 through the third capacitor C3; The second port of the transformer T1 is connected between the source of the seventh switching transistor Q7 and the drain of the eighth switching transistor Q8; The third port of the transformer T1 is connected between the source of the eleventh switching transistor Q11 and the drain of the twelfth switching transistor Q12; The fourth port of the transformer T1 is connected between the source of the ninth switching transistor Q9 and the drain of the tenth switching transistor Q10.

[0021] Optionally, each BUCK - BOOST module includes a fifth capacitor C5, a sixth capacitor C6, a thirteenth switching transistor Q13, a fourteenth switching transistor Q14, and a second inductor;

[0022] One end of the fifth capacitor C5 is connected to the positive terminal of the DC bus, and the other end is connected to the negative terminal of the DC bus;

[0023] The thirteenth switching transistor Q13 and the fourteenth switching transistor Q14 are connected in series. The drain of the thirteenth switching transistor Q13 is connected to the positive terminal of the DC bus, and the source of the fourteenth switching transistor Q14 is connected to the negative terminal of the DC bus;

[0024] One end of the second inductor L2 is connected between the source of the thirteenth switching transistor Q13 and the drain of the fourteenth switching transistor Q14, and the other end is connected to the positive terminal of the battery pack;

[0025] One end of the sixth capacitor C6 is connected between the second inductor L2 and the positive terminal of the battery pack, and the other end is connected to the negative terminal of the battery pack.

[0026] Optionally, the AC cooperation controller is also connected to the DC bus through a DC bus voltage sampling line for sampling the voltage of the DC bus.

[0027] The AC cooperation controller is also connected to three-phase mains through three-phase mains voltage sampling lines for sampling the voltage of the three-phase mains.

[0028] Optionally, the output ends of the multiple BUCK-BOOST modules are connected in parallel to form multiple independent channels, and each channel is respectively connected to a different battery cluster for independently performing charge and discharge tests on each battery cluster.

[0029] Optionally, the device further includes:

[0030] Multiple channel controllers, which are respectively arranged corresponding to the multiple independent channels. The input end of each channel controller is connected to the battery cluster under test for real-time collecting the voltage and current information of the battery cluster under test and transmitting the collected data to the middle computer; the output end of each channel controller is connected to the input end of the corresponding BUCK-BOOST module for controlling the voltage and current of the corresponding BUCK-BOOST module.

[0031] Optionally, the channel controller controls the output voltage and output current of the corresponding BUCK-BOOST module according to the collected voltage and current information of the battery cluster under test, so that the current is evenly distributed among the multiple BUCK-BOOST modules.

[0032] Optionally, based on the sampled DC bus voltage and three-phase mains voltage, the AC cooperation controller calculates the target current value of each isolated ACDC module through a control algorithm and sends a current distribution instruction to the multiple isolated ACDC modules to achieve current sharing control among the multiple isolated ACDC modules.

[0033] In a second aspect, the present invention also provides a high-power high-frequency modular battery cluster charge and discharge test method, and the method includes:

[0034] Sampling the three-phase mains voltage and the DC bus voltage through an AC cooperation controller, and calculating the target current value based on the sampling result;

[0035] Allocating the target current value to multiple isolated ACDC modules and controlling the multiple isolated ACDC modules to operate in current sharing;

[0036] Converting the DC bus voltage into a voltage adapted to the target battery cluster through multiple BUCK-BOOST modules to charge or discharge the target battery cluster.

[0037] Collect the voltage and current of the target battery cluster through a channel controller, adjust the output voltage and current of multiple BUCK-BOOST modules based on the collected data, and adjust the current distribution among the multiple BUCK-BOOST modules to achieve current sharing control.

[0038] According to the solution of the present invention, based on the above embodiments, through the modular design of an AC co-controller, multiple isolated ACDC modules, a DC bus, and multiple BUCK-BOOST modules, a highly integrated and modular architecture of the device is achieved. The high-power high-frequency modular battery cluster charge and discharge test equipment of the present invention can efficiently convert three-phase mains electricity into direct current and transmit it to multiple BUCK-BOOST modules through the DC bus, supporting the charge and discharge test of the target battery cluster. The modular design enables the device to be flexibly expanded at different power and current levels, significantly reducing the types and quantities of devices and simplifying the R & D, production, and after-sales processes. At the same time, the setting of isolated ACDC modules realizes voltage conversion and electrical isolation, with advantages such as low noise, small size, and light weight, improving the conversion efficiency and meeting complex test requirements.

[0039] Furthermore, through the AC co-controller to achieve precise current distribution for multiple isolated ACDC modules, the system can maintain current sharing operation, significantly improving stability and operating efficiency. At the same time, the independent adjustment of multiple BUCK-BOOST modules ensures precise control during the charge and discharge process of the battery cluster, optimizing the dynamic response performance of the device. This design not only improves the accuracy and reliability of the test but also enhances the adaptability of the device in complex test environments, improving the overall conversion efficiency and operating performance of the system. In addition, by connecting multiple BUCK-BOOST modules to the target battery cluster, multi-channel parallel operation can be achieved, and energy exchange can be carried out between multiple battery clusters, greatly improving the test efficiency and power utilization rate of the system and further optimizing the performance of the device.

[0040] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly and implement it according to the content of the specification, the following takes the preferred embodiments of the present invention as detailed descriptions as follows. Brief Description of the Drawings

[0041] Figure 1 Shows a schematic diagram of a high-power high-frequency modular battery cluster charge and discharge test equipment according to an embodiment of the present invention;

[0042] Figure 2 Shows a circuit diagram of an isolated ACDC module according to an embodiment of the present invention;

[0043] Figure 3The circuit diagram of a BUCK - BOOST module according to an embodiment of the present invention is shown;

[0044] Figure 4 The schematic flow chart of a high - power high - frequency modular battery cluster charge - discharge test method according to an embodiment of the present invention is shown. Detailed implementation manners

[0045] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following will, with reference to the accompanying drawings, make a detailed description of the detailed implementation manners of the present invention. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the drawings. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0046] The terms "including" and "having" in the present invention and any variations thereof are intended to cover non - exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0047] Referring to "embodiments" herein means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0048] Existing battery cluster charge and discharge equipment usually adopts a combined solution of a power frequency transformer, a high-power AC-DC bidirectional converter, and a BUCK-BOOST DC-DC bidirectional converter. This solution is widely adopted due to its stability, reliability, and technological maturity. The power frequency transformer can provide good voltage isolation and overload protection, and its stability and durability have been verified in high-power and high-current applications for a long time. However, the power frequency transformer is bulky, heavy, and has low efficiency. Especially in high-frequency and high-power applications, the volume and weight of the transformer restrict the energy efficiency and response speed of the overall equipment. In addition, the power frequency transformer has poor adjustment flexibility and is difficult to quickly adapt to the dynamically changing requirements during the complex battery charging and discharging process. Since this technical solution has been applied and verified for a long time, and has a high market acceptance and a large amount of usage experience, the industry has gradually formed a technical prejudice, generally believing that this is the most reliable and stable solution. Therefore, many developers and designers tend to continue this traditional thinking mode and lack the exploration and attempt of new solutions. This inertial thinking restricts the breakthrough of new technologies and makes it difficult for innovative technologies to enter the mainstream application fields.

[0049] After breaking the existing technical prejudice, the inventor chose to use an LLC isolated DCDC converter for voltage conversion and isolation. However, in the initial stage of R & D, the inventor still faced many challenges and technical problems.

[0050] In the initial R & D process, the inventor adopted a three-phase DNPC (Dual Active Bridge with NeutralPoint Clamped) unit as the current conversion module and worked independently, while connecting the LLC isolated DCDC unit and the BUCK-BOOST module into an integrated module for voltage conversion and isolation. Although this design can meet the basic voltage conversion and isolation requirements, in actual applications, there are significant problems of increased cost and power loss. The reason is that when the two measured battery clusters in the dual channels are in the charging and discharging states respectively, the energy exchange needs to pass through the LLC isolated DCDC unit, thus introducing additional energy conversion losses. This is because in this design, even if only one channel needs voltage conversion, the energy of the other channel still needs to pass through the LLC isolated DCDC unit, forming unnecessary losses and reducing the overall efficiency.

[0051] In addition, when the three-phase DNPC unit operates independently for the current conversion module, it is usually directly connected to the three-phase mains power supply for current conversion. Although this solution can theoretically achieve current conversion, it also brings a series of technical and systematic problems. First of all, the lack of an accurate current regulation and distribution mechanism leads to uneven current distribution among the modules. This current imbalance will cause an increase in power loss, thereby reducing the overall system efficiency. In addition, since the three-phase DNPC unit is operating as a voltage source at this time, there is no effective parallel connection ability at the output end, and a stable DC bus cannot be formed. This makes it impossible for multiple modules to work in coordination, seriously affecting the scalability and reliability of the system. In the absence of effective current management, the system may cause some modules to be overloaded and even damaged, increasing the risk of equipment failure. At the same time, this design limits the adaptability of the system in high-voltage and high-power scenarios, significantly affecting the working stability and long-term operation ability of the equipment.

[0052] Therefore, although the inventor broke the traditional technical prejudice and used the solution of a three-phase DNPC module and an LLC isolated DCDC module independently in the initial R & D process, the current conversion and voltage conversion functions could not be effectively integrated, resulting in problems such as excessive system power consumption and high cost. Through continuous optimization and improvement, the high-power high-frequency modular battery cluster charge and discharge test equipment and method of the present invention were finally introduced and proposed, breaking the limitations of the traditional design and achieving the efficient and stable operation of the battery cluster charge and discharge test equipment.

[0053] Figure 1 The schematic diagram of the high-power high-frequency modular battery cluster charge and discharge test equipment according to an embodiment of the present invention is shown. As Figure 1 shown, the equipment includes:

[0054] An AC co-controller, connected to the middle computer, for receiving the instructions transmitted by the middle computer and distributing current to multiple isolated ACDC modules.

[0055] Multiple isolated ACDC modules, the input ends of the multiple isolated ACDC modules are connected in parallel and then connected to the AC co-controller and the three-phase mains power supply, and the output ends are connected in parallel to form a DC bus, for converting alternating current into direct current and achieving voltage isolation.

[0056] The input ends of multiple isolated AC-DC modules are connected in parallel and then connected to the CANBUS port of the AC cooperation controller to receive the current distribution instructions sent by the AC cooperation controller. At the same time, the input ends of multiple isolated AC-DC modules are also connected in parallel to the three-phase mains power supply, which is used to convert the three-phase AC power of the mains into direct current to provide the DC voltage required by the device. In addition, since the AC cooperation controller distributes the target current value to each isolated AC-DC module and controls its output current to remain at this set value, multiple isolated AC-DC modules act as current sources and their output ends can be connected in parallel. The output ends of multiple isolated AC-DC modules are connected in parallel to form a DC bus, which unifies and converges the converted direct current and provides it to other modules in the device to ensure the stability of the DC voltage and be able to supply power to multiple BUCK-BOOST modules. The DC bus plays the role of power distribution and voltage stabilization, providing reliable power support for each module of the device, while simplifying power transmission and management. In addition, the voltage isolation function of multiple isolated AC-DC modules can effectively prevent the impact of mains voltage fluctuations and interference on the device, protecting other components in the system from grid interference, thereby improving the stability and reliability of the device.

[0057] Multiple BUCK-BOOST modules. The input ends of multiple BUCK-BOOST modules are connected in parallel and then connected to the DC bus. The output ends of multiple BUCK-BOOST modules are connected in parallel and then connected to the target battery cluster, which is used to test the charge and discharge of the target battery cluster.

[0058] Multiple BUCK-BOOST modules are connected in parallel to the DC bus through their input ends, converting the DC voltage into a voltage suitable for the target battery cluster and undertaking the charge and discharge test tasks of the battery cluster. Each BUCK-BOOST module can independently adjust the output voltage and current to ensure precise control during the charge and discharge process of the battery cluster and meet the voltage and current requirements of different battery clusters. The efficient design of multiple BUCK-BOOST modules improves the energy conversion efficiency, reduces energy loss, and ensures the stability and accuracy during the battery cluster test process. This design can provide reliable power supply during parallel testing of multiple battery clusters, ensuring the safety and efficiency of the device under long-term high-load operation.

[0059] According to the above embodiments, through the modular design of an AC coordination controller, multiple isolated ACDC modules, a DC bus, and multiple BUCK-BOOST modules, a highly integrated and modular architecture of the device is achieved. The high-power high-frequency modular battery cluster charge and discharge test equipment of the present invention can efficiently convert three-phase mains power into direct current and transmit it to multiple BUCK-BOOST modules through the DC bus, supporting the charge and discharge tests of the target battery cluster. The modular design enables the device to be flexibly expanded at different power and current levels, significantly reducing the types and quantities of devices and simplifying the R & D, production, and after-sales processes. At the same time, the setting of isolated ACDC modules realizes voltage conversion and electrical isolation, with advantages such as low noise, small size, and light weight, improving the conversion efficiency and meeting complex test requirements.

[0060] In some embodiments, referring to Figure 1 , the AC coordination controller of the high-power high-frequency modular battery cluster charge and discharge test equipment of the present invention is also connected to the DC bus through a DC bus voltage sampling line for sampling the voltage of the DC bus. The AC coordination controller is also connected to the three-phase mains power through a three-phase mains voltage sampling line for sampling the voltage of the three-phase mains power.

[0061] The AC coordination controller monitors the voltage of the DC bus in real time through the DC bus voltage sampling line and collects the mains voltage information through the three-phase mains voltage sampling line. These data are used to dynamically adjust the system parameters to ensure that the DC bus voltage remains within a safe and stable range, avoiding damage to the device and the battery cluster caused by overvoltage or undervoltage. At the same time, the mains voltage fluctuation is sampled in real time to optimize the adaptability of the device, ensure the stability of voltage conversion and current distribution, and thus improve the overall system operation efficiency and test accuracy. This process effectively improves the system stability, device protection ability, and performance optimization, ensuring the accuracy and reliability of the battery cluster charge and discharge test.

[0062] In some embodiments, based on the sampled DC bus voltage and three-phase mains voltage, the AC coordination controller calculates the target current value of each isolated ACDC module through a control algorithm and sends a current distribution instruction to the multiple isolated ACDC modules to achieve current sharing control among the multiple isolated ACDC modules.

[0063] The AC communication controller samples the DC bus voltage and three-phase mains voltage, calculates the target current value for each isolated ACDC module using a control algorithm, and sends current distribution instructions to multiple isolated ACDC modules. Through this process, the system can achieve current sharing control among the isolated ACDC modules, balancing the workload of each module. The current sharing control optimizes the use of power resources by precisely allocating the load of each module, improves the overall efficiency of the system, and reduces energy losses. It effectively avoids voltage fluctuations and current surges caused by uneven current, thereby enhancing the stability of the equipment, especially suitable for high-power, high-frequency battery test equipment. In addition, the current sharing control ensures that each module operates within a reasonable load range, reduces the risk of overload and overheating, extends the service life of the equipment, and reduces maintenance costs. During the charge and discharge test of the battery cluster, the current sharing control also ensures precise current distribution, eliminates test errors caused by uneven current, and guarantees test accuracy. Ultimately, the current sharing control greatly reduces the risk of equipment failure, providing system reliability and safety assurance.

[0064] In some embodiments, the output terminals of multiple BUCK-BOOST modules of the high-power high-frequency modular battery cluster charge and discharge test equipment of the present invention are connected in parallel to form multiple independent channels, and each channel is respectively connected to a different battery cluster for independent charge and discharge tests on each battery cluster.

[0065] The output terminals of multiple BUCK-BOOST modules can be connected in parallel to a single battery cluster to increase the power level. At the same time, they can also be connected to multiple different battery clusters to form multiple battery test channels. Multiple BUCK-BOOST modules are connected in parallel through the DC bus to form a common bus structure, which enables energy exchange between different test channels. Specifically, energy can be transferred between the test channels through the DC bus, greatly improving the overall efficiency of the system, avoiding the impact on the system when the load of a single channel is too high, and enabling the equipment to flexibly allocate energy between different battery clusters.

[0066] Reference Figure 1 , the output terminals of the first BUCK-BOOST module and the second BUCK-BOOST module are connected in parallel to form a first test channel for testing a target battery cluster. At the same time, the output terminals of the third BUCK-BOOST module and the fourth BUCK-BOOST module are connected in parallel to form a second test channel for testing another target battery cluster.

[0067] During the actual operation process, when the target battery clusters in the first test channel and the second test channel are both in the charging state, the output terminals of the first BUCK-BOOST module and the second BUCK-BOOST module in the first channel are connected in parallel to provide the required charging voltage and current for the first target battery cluster. At the same time, the output terminals of the third BUCK-BOOST module and the fourth BUCK-BOOST module in the second channel are connected in parallel to provide charging current for the other target battery cluster. During the discharge process of the battery cluster, the working principle is similar to that in the charging state. The first BUCK-BOOST module and the second BUCK-BOOST module in the first channel provide discharge current to adapt to the load requirements of the first battery cluster, and at the same time, adjust the output voltage and current through real-time current and voltage sampling to ensure precise control of the current during the battery discharge process. The working process of the third BUCK-BOOST module and the fourth BUCK-BOOST module in the second channel is similar and will not be elaborated here. When one target battery cluster is in the charging state and the other target battery cluster is in the discharging state, energy exchange can be achieved between the two target battery clusters through the DC bus. The target battery cluster in the discharging state can feedback energy to the DC bus, and this part of the energy can be used for the target battery cluster in the charging state to further improve the system efficiency.

[0068] Therefore, an energy exchange bridge is formed between the first test channel, the second test channel and the AC side through the DC bus. When the requirements of the target battery cluster change, the device can automatically perform energy distribution to ensure that the charging and discharging processes of each battery cluster can be maintained in the optimal working state. Through this energy exchange mechanism, the device not only improves the overall energy efficiency, but also ensures system stability when multiple battery clusters are tested simultaneously, avoiding the risk of overload.

[0069] In some embodiments, the high-power high-frequency modular battery cluster charge and discharge test device of the present invention further includes a plurality of channel controllers, which are respectively arranged corresponding to the plurality of independent channels. The input end of each channel controller is connected to the battery cluster under test, and is used to collect the voltage and current information of the battery cluster under test in real time and transmit the collected data to the middle computer; the output end of each channel controller is connected to the input end of the corresponding BUCK-BOOST module, and is used to control the voltage and current of the corresponding BUCK-BOOST module.

[0070] Multiple channel controllers are connected to the corresponding channels under test through channel voltage and current sampling lines, and they collect the voltage and current data of the battery cluster under test in real time. Then, the collected data is transmitted to the middle computer through a communication interface (such as CAN bus or other transmission methods). After receiving the data, the middle computer conducts necessary data analysis and processing, and calculates the required voltage and current parameters according to the test requirements. Based on the processing results, the middle computer sends corresponding control instructions to each channel controller. The channel controller controls the corresponding BUCK-BOOST module through these instructions to adjust the output voltage and current, so as to precisely meet the charge and discharge requirements of the battery cluster.

[0071] By collecting the voltage and current data of the battery cluster in real time and combining with the precise calculation of the middle computer, the channel controller ensures precise control and efficient regulation during the charge and discharge process, thus improving the test accuracy and the stability of the equipment. Each channel controller independently controls the corresponding BUCK-BOOST module, avoiding interference between channels, enhancing the adaptability and flexibility of the system, especially outstanding in the parallel test of multiple battery clusters. This independent control method enables the equipment to quickly respond to the dynamic changes of the battery cluster, provide personalized charge and discharge schemes, optimize the test efficiency, and ensure the long-term stable operation of the equipment.

[0072] In some embodiments, the channel controller controls the output voltage and output current of the corresponding BUCK-BOOST module according to the collected voltage and current information of the battery cluster under test, so that the current is evenly distributed among multiple BUCK-BOOST modules. Each channel controller monitors the voltage and current status of the battery cluster under test in real time, and transmits the collected data to the middle computer for processing. The middle computer calculates the required output current and voltage of each BUCK-BOOST module according to the voltage and current data of the battery cluster and the preset charge and discharge strategy. The middle computer generates control instructions according to the calculation results and sends these instructions to each channel controller. After receiving the control instructions, the channel controller adjusts the output voltage and current of the corresponding BUCK-BOOST module to ensure that the current output by each module is evenly distributed, thus avoiding the situation of overload of a certain module or insufficient current of some modules. Through precise current control, all BUCK-BOOST modules maintain load balance when working in parallel, ensuring the stability and precision of the charge and discharge process of the battery cluster. When multiple battery clusters work simultaneously, the even distribution of current can also effectively avoid interference between them, improving the overall efficiency and stability of the system.

[0073] Through the precise adjustment of each BUCK - BOOST module by the channel controller, it is ensured that the current is evenly distributed among multiple modules during the charging and discharging processes, they jointly bear the load, and energy waste, test errors, and equipment damage caused by unbalanced loads are avoided. This design not only improves the efficiency and stability of the system, but also enhances the test accuracy, extends the service life of the equipment, and effectively reduces the failure risk, providing a reliable guarantee for the charging and discharging tests of high - power battery clusters.

[0074] Figure 2 The circuit diagram of an isolated AC - DC module according to an embodiment of the present invention is shown. As Figure 2 shown, each isolated AC - DC module includes:

[0075] A three - phase DNPC topology unit, including a first capacitor C1, a second capacitor C2, a first switching transistor Q1, a second switching transistor Q2, a third switching transistor Q3, a fourth switching transistor Q4, a first inductor L1, a first diode D1, and a second diode D2.

[0076] The first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are connected in series. The collector of the first switching transistor Q1 is connected to the positive pole of the power supply, and the emitter of the fourth switching transistor Q4 is connected to the negative pole of the power supply.

[0077] The first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are IGBT devices, which are connected in series to form a bridge - arm structure. By controlling the conduction and cut - off of these switching transistors, the three - phase AC voltage is rectified into a DC voltage, realizing the rectification and energy transfer of the AC voltage.

[0078] One end of the first capacitor C1 is connected to the collector of the first switching transistor Q1, and the other end is connected to the B - phase mains input and the C - phase mains input. One end of the first inductor L1 is connected between the emitter of the second switching transistor Q2 and the collector of the third switching transistor Q3, and the other end is connected to the A - phase mains input. The cathode of the first diode D1 is connected between the emitter of the first switching transistor Q1 and the collector of the second switching transistor Q2, and the anode of the first diode D1 is grounded; the anode of the second diode D2 is connected between the emitter of the third switching transistor Q3 and the collector of the fourth switching transistor Q4, and the cathode of the second diode D2 is grounded. One end of the second capacitor C2 is connected to the A - phase mains input, and the other end is grounded.

[0079] The first inductor L1 is connected to the A-phase mains input and functions to store energy and filter. When the switching transistor switches, the inductor can prevent sudden changes in current and make the current smoother. The first capacitor C1 is connected between the collector of the first switching transistor Q1 and the B-phase and C-phase mains inputs, functioning to filter and store energy, which helps to stabilize the voltage. The second capacitor C2 is connected between the A-phase mains input and ground for further filtering to reduce voltage fluctuations. The first diode D1 and the second diode D2 clamp the midpoint voltage respectively to ensure the smoothness and symmetry of the output voltage, and at the same time function to suppress voltage spikes. The cathode of the first diode D1 is connected between the emitter of the first switching transistor Q1 and the collector of the second switching transistor Q2, and the anode is grounded, which is used to clamp the midpoint voltage between Q1 and Q2. The anode of the second diode D2 is connected between the emitter of the third switching transistor Q3 and the collector of the fourth switching transistor Q4, and the cathode is grounded to ensure the stability of the midpoint voltage between Q3 and Q4. When the switching transistor is turned off, the current in the inductor cannot change suddenly, and the diode provides a freewheeling path for the inductor current to prevent the generation of voltage spikes.

[0080] The three-phase DNPC topology is adopted. Through the neutral-point clamping technology, the voltage stress of the switching devices is reduced, the energy loss is decreased, and the rectification efficiency is improved. At the same time, due to the high-frequency operation of the switching transistors Q1 - Q4, compared with the traditional power-frequency scheme, the efficiency is higher and it is suitable for high-power scenarios. Compared with the traditional power-frequency transformer scheme, the isolated AC-DC module adopts high-frequency switching technology, has a smaller volume, lighter weight, and lower noise, meeting the requirements of the new energy vehicle and energy storage industries for equipment lightweight and quiet operation.

[0081] In some embodiments, each isolated AC-DC module further includes:

[0082] LLC isolated DC-DC unit, including transformer T1, third capacitor C3, fourth capacitor C4, fifth switch Q5, sixth switch Q6, seventh switch Q7, eighth switch Q8, ninth switch Q9, tenth switch Q10, eleventh switch Q11 and twelfth switch Q12. The fifth switch Q5 and the sixth switch Q6 are connected in series. The drain of the fifth switch Q5 is connected to the positive power supply, and the source of the sixth switch Q6 is connected to the negative power supply; the seventh switch Q7 and the eighth switch Q8 are connected in series. The drain of the seventh switch Q7 is connected to the positive power supply, and the source of the eighth switch Q8 is connected to the negative power supply. The ninth switch Q9 and the tenth switch Q10 are connected in series. The drain of the ninth switch Q9 is connected to the positive pole of the DC bus, and the source of the tenth switch Q10 is connected to the negative pole of the DC bus; the eleventh switch Q11 and the twelfth switch Q12 are connected in series. The drain of the eleventh switch Q11 is connected to the positive pole of the DC bus, and the source of the twelfth switch Q12 is connected to the negative pole of the DC bus; one end of the fourth capacitor is connected to the positive pole of the DC bus, and the other end is connected to the negative pole of the DC bus. The first port of the transformer T1 is connected between the source of the fifth switch Q5 and the drain of the sixth switch Q6 through the third capacitor C3; the second port of the transformer T1 is connected between the source of the seventh switch Q7 and the drain of the eighth switch Q8; the third port of the transformer T1 is connected between the source of the eleventh switch Q11 and the drain of the twelfth switch Q12; the fourth port of the transformer T1 is connected between the source of the ninth switch Q9 and the drain of the tenth switch Q10.

[0083] The fifth switching transistor Q5 and the sixth switching transistor Q6 are connected in series, and the seventh switching transistor Q7 and the eighth switching transistor Q8 are connected in series. They form the primary-side switching network of the LLC resonant converter. By controlling the conduction and cutoff of these switching transistors, a high-frequency square-wave voltage can be generated on the primary side of the transformer T1. For example, when Q5 and Q8 are conducting, the current flows from the positive pole of the power supply through Q5, the primary winding of the transformer T1, Q8 and back to the negative pole of the power supply, forming a forward current path. The ninth switching transistor Q9 and the tenth switching transistor Q10 are connected in series, and the eleventh switching transistor Q11 and the twelfth switching transistor Q12 are connected in series. They form the secondary-side switching network. The control of the secondary-side switching transistors is coordinated with the control of the primary-side switching transistors to achieve the transfer of energy from the primary side to the secondary side. For example, when Q5 and Q8 on the primary side are conducting, the corresponding switching transistors on the secondary side (such as Q9 and Q12) will also conduct to achieve the transfer of energy. The third capacitor C3 is connected between the first port of the transformer T1 and the primary-side switching transistors (Q5 and Q6). Together with the leakage inductance and magnetizing inductance of the transformer, it forms the LLC resonant circuit. This resonant circuit can achieve zero-voltage switching (ZVS) of the switching transistors, reducing switching losses. The fourth capacitor C4 is connected between the positive and negative poles of the DC bus, playing a role in filtering and energy storage, which helps to stabilize the DC bus voltage. The transformer T1 plays a role in electrical isolation and voltage conversion. It transfers the energy on the primary side to the secondary side through the principle of electromagnetic induction, and can increase or decrease the voltage according to the turns ratio.

[0084] The LLC isolated DC-DC unit realizes electrical isolation between the input and output sides through the transformer T1, ensuring the electrical safety of the system. Its flexible adjustment ability of the duty cycle and operating frequency of the switching transistors enables it to adapt to diverse load requirements and achieve precise output voltage regulation. At the same time, the built-in resonant circuit effectively reduces electromagnetic interference and improves the electromagnetic compatibility performance; the reasonable circuit design and component selection significantly reduce the device stress and extend the system life, thus improving the overall reliability. This unit has the ability of efficient, stable and reliable DC-DC power conversion and is suitable for a variety of application scenarios.

[0085] Figure 3 The circuit diagram of the BUCK-BOOST module according to an embodiment of the present invention is shown. As Figure 3 shown, each BUCK-BOOST module includes:

[0086] The fifth capacitor C5, the sixth capacitor C6, the thirteenth switching transistor Q13, the fourteenth switching transistor Q14, and the second inductor. One end of the fifth capacitor C5 is connected to the positive pole of the DC bus, and the other end is connected to the negative pole of the DC bus. The thirteenth switching transistor Q13 and the fourteenth switching transistor Q14 are connected in series. The drain of the thirteenth switching transistor Q13 is connected to the positive pole of the DC bus, and the source of the fourteenth switching transistor Q14 is connected to the negative pole of the DC bus. One end of the second inductor L2 is connected between the source of the thirteenth switching transistor Q13 and the drain of the fourteenth switching transistor Q14, and the other end is connected to the positive pole of the battery cluster. One end of the sixth capacitor C6 is connected between the second inductor L2 and the positive pole of the battery cluster, and the other end is connected to the negative pole of the battery cluster.

[0087] The thirteenth switching transistor Q13 and the fourteenth switching transistor Q14 are connected in series to form a basic Buck - Boost topology. When the thirteenth switching transistor Q13 is turned on and the fourteenth switching transistor Q14 is turned off, current flows from the positive pole of the DC bus through the thirteenth switching transistor Q13 and the inductor L2 to charge the battery cluster, and at this time the circuit operates in the buck mode. When the thirteenth switching transistor Q13 is turned off and the fourteenth switching transistor Q14 is turned on, the energy in the inductor L2 is released through the fourteenth switching transistor Q14 and the battery cluster, and at this time the circuit operates in the boost mode. The fifth capacitor C5 is connected between the positive and negative poles of the DC bus, playing a role in filtering and energy storage, which helps to stabilize the DC bus voltage. The sixth capacitor C6 is connected between the inductor L2 and the battery cluster for filtering to reduce the voltage fluctuation at the battery cluster end.

[0088] The Buck - Boost module realizes bidirectional voltage conversion by controlling the switching transistors Q13 and Q14, can flexibly adjust the voltage rise and fall between the DC bus and the battery cluster, and improves the adaptability and flexibility of the system. Its topology is efficient and energy - saving, reducing energy loss. The filtering functions of the capacitors C5 and C6 can suppress voltage fluctuations, improve the power quality and protect components. Precise voltage control avoids over - charging and over - discharging of the battery, prolongs the battery life, and reasonable design reduces component stress and improves system reliability, which is suitable for DC systems and battery management.

[0089] In summary, according to the above embodiments, it can be seen that the technical solution of the present invention realizes precise current distribution for multiple isolated ACDC modules through an AC coordination controller. The system can maintain current sharing operation, significantly improving stability and operating efficiency. At the same time, the independent regulation of multiple BUCK - BOOST modules ensures precise control during the charging and discharging processes of the battery cluster, optimizing the dynamic response performance of the device. This design not only improves the accuracy and reliability of testing, but also enhances the adaptability of the device in complex testing environments, improving the overall conversion efficiency and operating performance of the system. Additionally, by connecting multiple BUCK - BOOST modules to the target battery cluster, multi - channel parallel operation can be achieved, and energy exchange can be carried out between multiple battery clusters, greatly improving the testing efficiency and power utilization rate of the system, and further optimizing the performance of the device.

[0090] Figure 4 The flowchart shows a high - power high - frequency modular battery cluster charging and discharging test method according to an embodiment of the present invention. As Figure 4 shown, the high - power high - frequency modular battery cluster charging and discharging test method includes the following steps:

[0091] Step S100, sample the three - phase mains voltage and the DC bus voltage through an AC coordination controller, and calculate the target current value based on the sampling results.

[0092] Step S200, distribute the target current value to multiple isolated ACDC modules, and control the multiple isolated ACDC modules to operate with current sharing.

[0093] Step S300, convert the DC bus voltage to a voltage suitable for the target battery cluster through multiple BUCK - BOOST modules, and charge or discharge the target battery cluster.

[0094] Step S400, collect the voltage and current of the target battery cluster through a channel controller, adjust the output voltage and current of multiple BUCK - BOOST modules based on the collected data, and adjust the current distribution between multiple BUCK - BOOST modules to achieve current sharing control.

[0095] In the above high - power high - frequency modular battery cluster charging and discharging test method, the specific implementation manners of each module and unit refer to the relevant content of the embodiments in the above high - power high - frequency modular battery cluster charging and discharging test equipment, and will not be elaborated here.

[0096] The technical features of the above - described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above - described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0097] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A high-power high-frequency modular battery cluster charge and discharge test equipment, characterized in that: The device comprises: An AC co-controller, connected to the intermediate computer, for receiving instructions transmitted by the intermediate computer and distributing current to a plurality of isolated ACDC modules; A plurality of isolated ACDC modules, wherein the input ends of the plurality of isolated ACDC modules are connected in parallel to the AC cooperative controller and the three-phase mains power supply, and the output ends are connected in parallel to form a DC bus for converting AC power into DC power and realizing voltage isolation; A plurality of BUCK-BOOST modules, wherein input ends of the plurality of BUCK-BOOST modules are connected in parallel to the DC bus, and output ends of the plurality of BUCK-BOOST modules are connected in parallel to a target battery cluster, for testing the charge and discharge of the target battery cluster; the plurality of BUCK-BOOST modules can exchange energy through the DC bus; The AC cooperative controller is also connected to the DC bus through a DC bus voltage sampling line, and is used to sample the voltage of the DC bus; The AC cooperative controller is also connected to the three-phase mains via a three-phase mains voltage sampling line, and is used to sample the voltage of the three-phase mains; The AC cooperative controller calculates the target current value of each isolated ACDC module based on the sampled DC bus voltage and the three-phase mains voltage through a control algorithm, and sends a current distribution instruction to the multiple isolated ACDC modules to achieve current sharing control among the multiple isolated ACDC modules.

2. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 1 is characterized in that: Each isolated ACDC module includes: A three-phase DNPC topology unit includes a first capacitor C1, a second capacitor C2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first inductor L1, a first diode D1 and a second diode D2; The first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are connected in series, the collector of the first switch tube Q1 is connected to the positive electrode of the power supply, and the emitter of the fourth switch tube Q4 is connected to the negative electrode of the power supply; One end of the first capacitor is connected to the collector of the first switch tube Q1, and the other end is connected to the B-phase mains input and the C-phase mains input; One end of the first inductor L1 is connected between the emitter of the second switch tube Q2 and the collector of the third switch tube Q3, and the other end is connected to the A-phase mains input; The cathode of the first diode D1 is connected between the emitter of the first switch tube Q1 and the collector of the second switch tube Q2, and the anode of the first diode D1 is grounded; the anode of the second diode D2 is connected between the emitter of the third switch tube Q3 and the collector of the fourth switch tube Q4, and the cathode of the second diode D2 is grounded; One end of the second capacitor C2 is connected to the A-phase mains input, and the other end is grounded.

3. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 1, characterized in that: Each isolated ACDC module also includes: The LLC isolated DCDC unit includes a transformer T1, a third capacitor C3, a fourth capacitor C4, a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7, an eighth switch tube Q8, a ninth switch tube Q9, a tenth switch tube Q10, an eleventh switch tube Q11 and a twelfth switch tube Q12; The fifth switch tube Q5 and the sixth switch tube Q6 are connected in series, the drain of the fifth switch tube Q5 is connected to the positive electrode of the power supply, and the source of the sixth switch tube Q6 is connected to the negative electrode of the power supply; the seventh switch tube Q7 and the eighth switch tube Q8 are connected in series, the drain of the seventh switch tube Q7 is connected to the positive electrode of the power supply, and the source of the eighth switch tube Q8 is connected to the negative electrode of the power supply; The ninth switch tube Q9 and the tenth switch tube Q10 are connected in series, the drain of the ninth switch tube Q9 is connected to the positive electrode of the DC bus, and the source of the tenth switch tube Q10 is connected to the negative electrode of the DC bus; the eleventh switch tube Q11 and the twelfth switch tube Q12 are connected in series, the drain of the eleventh switch tube Q11 is connected to the positive electrode of the DC bus, and the source of the twelfth switch tube Q12 is connected to the negative electrode of the DC bus; one end of the fourth capacitor is connected to the positive electrode of the DC bus, and the other end is connected to the negative electrode of the DC bus; The first port of the transformer T1 is connected between the source of the fifth switch tube Q5 and the drain of the sixth switch tube Q6 through the third capacitor C3; the second port of the transformer T1 is connected between the source of the seventh switch tube Q7 and the drain of the eighth switch tube Q8; the third port of the transformer T1 is connected between the source of the eleventh switch tube Q11 and the drain of the twelfth switch tube Q12; the fourth port of the transformer T1 is connected between the source of the ninth switch tube Q9 and the drain of the tenth switch tube Q10.

4. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 1, characterized in that: Each BUCK-BOOST module includes a fifth capacitor C5, a sixth capacitor C6, a thirteenth switch tube Q13, a fourteenth switch tube Q14 and a second inductor L2; One end of the fifth capacitor C5 is connected to the positive electrode of the DC bus, and the other end is connected to the negative electrode of the DC bus; The thirteenth switch tube Q13 and the fourteenth switch tube Q14 are connected in series, the drain of the thirteenth switch tube Q13 is connected to the positive electrode of the DC bus, and the source of the fourteenth switch tube Q14 is connected to the negative electrode of the DC bus; One end of the second inductor L2 is connected between the source of the thirteenth switch tube Q13 and the drain of the fourteenth switch tube Q14, and the other end is connected to the positive electrode of the battery cluster; One end of the sixth capacitor C6 is connected between the second inductor L2 and the positive electrode of the battery cluster, and the other end is connected to the negative electrode of the battery cluster.

5. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 1, characterized in that: The output ends of the multiple BUCK-BOOST modules are connected in parallel to form multiple independent channels, and each channel is connected to a different battery cluster, so as to perform independent charge and discharge tests on each battery cluster.

6. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 5, characterized in that: The device also includes: A plurality of channel controllers are respectively arranged corresponding to the plurality of independent channels, and an input end of each channel controller is connected to the battery cluster under test, so as to collect voltage and current information of the battery cluster under test in real time, and transmit the collected data to the intermediate computer; an output end of each channel controller is connected to an input end of a corresponding BUCK-BOOST module, so as to control the voltage and current of the corresponding BUCK-BOOST module.

7. The high-power high-frequency modular battery cluster charge and discharge test equipment according to claim 6, characterized in that: The channel controller controls the output voltage and output current of the corresponding BUCK-BOOST module according to the collected voltage and current information of the tested battery cluster, so that the current is evenly distributed among the multiple BUCK-BOOST modules.

8. A high-power high-frequency modular battery cluster charge and discharge test method for the device as claimed in any one of claims 6-7, characterized in that: The method comprises: The three-phase mains voltage and the DC bus voltage are sampled by the AC cooperative controller, and the target current value is calculated based on the sampling results; Distribute the target current value to multiple isolated ACDC modules, and control the multiple isolated ACDC modules to operate in current-sharing mode; The DC bus voltage is converted into a voltage suitable for the target battery cluster through multiple BUCK-BOOST modules to charge or discharge the target battery cluster; The voltage and current of the target battery cluster are collected by a channel controller, the output voltage and current of multiple BUCK-BOOST modules are adjusted based on the collected data, and the current distribution between the multiple BUCK-BOOST modules is adjusted to achieve current sharing control.

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