具备故障重构能力的双极直流接口变换器最优运行区域

Optimal Working Zone of DC-DC Interface Converter for Bipolar DC Distribution System With Fault-tolerant Capability

中低压直流配电系统中,现有的双极直流接口变换器通常无法在进入单极运行模式下实现故障阻断与重构功能。基于一种互联分布式电源与双极直流系统的故障重构型直流接口变换器拓扑,分析单双极性运行模式的工作性能。在正常的双极运行模式下,变换器通过最小峰值电流控制策略,实现开关器件电流应力有效降低。在短路故障导致的单极运行模式下,变换器通过故障重构策略与恒功率传输控制策略,消除短路故障对正常端口的不利影响,维持关键负荷的连续供电。同时给出变换器在单双极模式的优化控制策略下的软开关运行区域,从而精确刻画出变换器的最优运行区域。实验结果证明理论分析的正确性,研究工作有助于指导中低压直流配电系统的工程实践。

The conventional DC-DC interface converter lacks of fault blocking and reconfiguration capability under monopolar mode in low/medium voltage DC system.In this article,a type of DC-DC converter with fault-tolerant capability is used to interconnect bipolar DC system and distributed energy source.Working performance of the DC-DC converter is exhaustively analyzed under monopolar/bipolar mode.Under bipolar mode,the minimized-peak-current control strategy is designed to reduce current stress on switching devices of the converter.Under monopolar mode caused by the short-circuit,the fault reconfiguration method and constant-transmitted-power control strategy are designed to eliminate fault impact on the normally operating terminals and ensure uninterrupted power supply to critical load.Further,ZVS operation area of the converter under optimizing control strategies in bipolar/monopolar mode is analyzed in order to depict optimal working zone.Finally,theoretical analyses have been tested in experimental prototype for correctness verification.The research in this article is supportive to engineering project of low/medium voltage DC systems.