基于旋转电容的直流电网软开关DC-DC变换器设计

Soft-Switching DC/DC Converter Design for DC Grid Based on Rotating Capacitor

作为连接不同电压等级直流母线的关键设备之一,DC-DC变换器转换效率的提高对于建立直流电网有重要意义。为了降低大功率软开关DC-DC变换器的体积和质量,基于旋转电容构造了一种能够实现功率器件零电流关断的非隔离型双向DC/DC变换器。介绍了变换器的电路拓扑结构;分析了不同模式下的稳态工作过程;设计了器件的具体参数及控制方案并研究了变换器的损耗特性;最后,在Matlab/Simulink中搭载仿真模型,验证了设计方案和控制策略的正确性。结果表明,所设计的变换器能够实现开关管和二极管的零电流关断,具有较高的转换效率。

As a key device to realize the interconnection betw een DC bus w ith different voltage levels,the improvement of DC-DC converter conversion efficiency is of great significance for establishing DC grid. This paper proposes a nonisolated bidirectional DC/DC converter based on rotating capacitor w ith zero-current-sw itching capability of pow er device,in order to reduce the volume and w eight of high-pow er soft-sw itching DC-DC converters. We introduce the circuit topology of the converter; analyze the steady state w orking process under different modes; design specific parameters and basic control scheme of the device and study the pow er loss characteristics of the converter; finally,verify the correctness of the design scheme and control strategy through the simulation model in M atlab/Simulink. The results show that the proposed converter can achieve zero-current-sw itching of sw itch and diode and has high conversion efficiency.