一种三相级联型电力电子变压器及其控制策略研究

摘要

针对直流微网的并网问题，设计一种三相级联型电力电子变压器，高压交流输入级采用星形级联型H桥拓扑，低压直流输出级使用输出并联的隔离式双向主动全桥结构。在直接接入交流配电网的同时，为分布式能源提供了一个稳定的直流接口。文中针对两级分别设计了闭环的控制方法，特别是对于高压级的星形级联型拓扑提出了一种简单的相间和相内直流侧平衡控制方法。通过仿真和实验验证了上述拓扑结构和控制策略的可行性和有效性。%A three-phase cascaded power electronic transformer ( PET) is designed for grid-connected DC micro-grid.It consists of star-connected cascaded H-bridge ( CHB) converters at the input stage and out-put-parallel isolated dual active bridges ( DAB) at the output stage.The proposed PET can be directly connected to high-voltage distribution network and provide a stable DC interface for distribute generation ( DG) .The closed-loop control methods were respectively designed for the two stages,in which a simple control method was proposed to balance inphase and interphase DC voltages of star-connected CHB con-verter in particular.The feasibility and validity of the proposed PET and its control strategy are verified by simulation and experiment.