基于三端口双向DC/DC变换器的高增益组合式交直流变换器

储能系统是保证新能源供电系统、微网及大电网安全、稳定、可靠运行的关键。为了应对储能电池电压低对双向交直流变换器电压增益和效率等带来的挑战,提出了一种基于高增益比三端口双向DC/DC变换器的组合式双向交直流变换器。基于交流侧电压周期性波动的特点,利用三端口双向DC/DC变换器同时提供高压母线端口和低压母线端口,使得部分功率仅需经过低电压增益直流变换环节处理,为高增益高效率双向交直流变换提供了有利条件。详细分析了双向组合式交直流变换器的系统架构和工作原理,给出了前后级变换器的调制和控制策略,并分析了组合式交直流变换器的功率传输特性。最后,通过实验结果验证了理论分析的正确性和所提方法的有效性。

High-gain Combined DC/AC Converter Based on Three-port Bidirectional DC/DC Converter

Energy storage systems are the key to guaranteeing the safe, stable and reliable operation of the new energy power supply system, micro grid and big grid. To confront the challenge to the voltage gain and efficiency of a bidirectional DC/AC converter brought by the low energy storage battery voltage, a high-gain combined bidirectional DC/AC converter is proposed based on a three-port bidirectional DC/DC converter. On the basis of the periodic fluctuation characteristics of AC voltage, the high-voltage and low-voltage bus ports are provided by means of the three-port bidirectional DC/DC converter at the same time, so that partial power only needs to be processed by a low-voltage gain DC/DC conversion link, which provides favorable conditions for a high-gain high-efficiency bidirectional DC/AC converter. The system architecture and operation principle for the bidirectional combined DC/AC converter are analyzed in detail, and the modulation and control strategies for the converter at the front and rear stages are given. In addition, the power transmission characteristics of the combined DC/AC converter are also analyzed. Finally, the ex-perimental results of a prototype verified the correctness of theoretical analysis and the effectiveness of the proposed method.