不平衡工况下AC/DC变流器的有源功率解耦拓扑

An Active Power Decoupling Topology for AC/DC Converter Under Unbalanced Conditions

AC/DC变流器在低压直流供电系统中被广泛应用。然而,在实际运行中存在着不同类型的电网扰动和故障,给变流器的正常运行带来了较大的挑战。电网不平衡就是这种异常情况之一,其会导致交流侧产生负序电流和直流侧产生较大的二倍频电压/电流脉动,从而降低系统的性能。目前控制策略在不平衡电网工况下较难同时实现平衡正弦的交流侧电流和恒定的直流电压/电流。为了解决上述问题,提出了一种三相有源功率解耦拓扑,分析了其工作原理以及拓扑参数的设计,最后实验结果表明该拓扑在不平衡工况下能同时实现交、直流两侧较高的电能质量。

AC/DC converters are widely used in low voltage DC power supply systems.However,there are different types of grid disturbances and faults in actual operation,which brings great challenges to the normal operation of the converter.Grid unbalance is one of the abnormal conditions,which causes the negative-sequence current on the AC side and the large double-frequency voltage/current pulsation on the DC side,which degrades the performance of the system.So far,the existing control strategy is difficult to achieve balanced sinusoidal AC side current and constant DC voltage/current under unbalanced grid conditions.In order to solve the above problems,a three-phase active power decoupling topology is proposed,its working principle and the topology parameters designs is analyzed.Finally,the experimental results show that the topology can achieve higher power quality on both sides of AC and DC under unbalanced conditions.