Abstract— This study proposes a multi-level power converter for a battery energy storage system (BESS) with bidirectional power flow. The multi-level power converter includes a DC-DC power converter, a selection switch set and a full-bridge inverter. The DC-DC power converter performs bidirectional power conversion and provides a DC voltage that is greater than the peak voltage of the utility. Integrating the selection switch set and the full-bridge inverter produces a five-level AC voltage that controls the real power flow and the reactive power flow between the battery set, the DC-DC power converter and the grid. Because partial power is directly processed using only the selection switch set and the full-bridge inverter, the DC-DC power converter is operated only when the grid voltage is greater than the voltage of the battery set. Therefore, the power conversion efficiency for the proposed BESS is improved. The proposed BESS uses only eight power electronic switches, so the power circuit is simplified. A hardware prototype with a digital signal processor controller is used to verify the performance of the proposed BESS. The experimental results are as expected.

中文翻译：

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一种用于电池储能系统的多电平电源转换器接口

摘要：本研究提出了一种用于具有双向功率流的电池储能系统 (BESS) 的多电平功率转换器。多电平功率变换器包括DC-DC功率变换器、选择开关组和全桥逆变器。DC-DC 电源转换器执行双向电源转换并提供大于市电峰值电压的直流电压。集成选择开关组和全桥逆变器产生五电平交流电压，控制电池组、DC-DC 电源转换器和电网之间的有功功率流和无功功率流。由于仅使用选择开关组和全桥逆变器直接处理部分功率，DC-DC功率变换器只有在电网电压大于电池组电压时才工作。所以，所提议的 BESS 的功率转换效率得到了提高。建议的 BESS 仅使用 8 个电力电子开关，因此简化了电源电路。带有数字信号处理器控制器的硬件原型用于验证所提出的 BESS 的性能。实验结果符合预期。