| Rapid economic development has brought high energy consumption, and the increasingly serious energy crisis and environmental pollution. Therefore, The development of new energy and the application of large scale have become the inevitable trend of the global energy application. New energy has lower density, instability and randomicity. With the energy storage technology’s development, the large-scale application of new energy becomes possible. Vanadium redox flow battery is a novel energy storage battery, especially in environmental protection. Vanadium redox flow battery has a broad market prospect, which has the advantages of long service life and the use of charging and so on. Therefore, as a conversion device in energy storage system, research on vanadium redox flow energy storage converter is very important.First of all, this paper analyzes the working principle of 5k W/20 k Wh vanadium redox flow battery, and describes its internal structure. The electrochemical and physical properties model is build for vanadium redox flow battery, which is based on establishment of vanadium redox flow battery equivalent circuit model. According to the vanadium redox flow battery equivalent circuit establish the modeling work of vanadium redox flow battery, and charge discharge characteristics of vanadium redox flow battery. Analysis the bidirectional DC/DC converter and bidirectional AC/DC converter principle based on the feature of vanadium redox flow battery. Which using the state space average method of bidirectional DC/DC converter is established the equivalent small signal model, and The bidirectional AC/DC converter with LCL filter, established in the abc static coordinate system, the ?? mathematical model of the stationary and the dq rotating coordinate system.Secondly, the four-stage control strategy of bidirectional DC/DC converter and the double closed loop PI control strategy of bidirectional AC/DC converter with LCL filter are put forward, which based on the feature of vanadium redox flow battery, the bidirectional DC/DC converter and the bidirectional AC/DC converter working principle and mathematical model. To analyze the theory and design of controller., According to the typical I type system design of the current regulator for improving the current tracking performance. According to the typical type II system design of voltage regulator for improving the voltage outer loop interference. Based on the mathematical model and controller design of the simulation model was built, through the comparison of the simulation experiments verify the correctness and validity of the proposed control strategy. At the same time, detailed design of the hardware system to determine the scheme of energy storage system based on, including the main circuit parameter calculation, sampling and signal conditioning circuit, drive circuit, protection circuit and so on.Finally, it’s based on the design of hardware and software to build a 5k W vanadium redox flow storage can converter experimental prototype by debugging and experiments of the prototype, the related experimental data and waveform, and the vanadium redox flow battery charging and discharging bidirectional DC/DC converter and bidirectional AC/DC converter with experimental data and waveform of the analysis and comparison. Clearance experiment waveforms show that the converter can well realize the basic functions of the battery charge and discharge the design of vanadium redox flow battery two-way reservoir. |
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