基于电力电子变压器的微网并网装置仿真研究

针对传统微网并网方式供电可靠性低、稳定性差、潮流无法控制等问题，该文设计了一种基于电力电子变压器的新型微网并网装置，提出了其在不同运行模式下的控制策略。对于电网跟随控制下的微网系统，并网装置采用V/f控制策略；对于微网并网点潮流恒定控制下的微网系统，并网装置采用PQ控制策略。利用电磁暂态仿真软件PSCAD/EMTDC对所提的控制策略进行了仿真，结果表明，该文提出的并网装置及控制策略不仅可实现微网与大电网的联网运行，还能精确控制并网点潮流，减小并网过程中微网DG、负荷波动时对主网的影响。

Simulation Study of Microgrid Connecting Device Based on Power Electronic Transformer

This paper constructs a novel topology of microgrid with power electronic transformer （ PET ） as grid-connected device .Based on this , a coordinated control strategy for grid-connected device was proposed . When microgrid operates in grid-following mode , V/f control strategy is used for output inverter of power electronic transformer .When constant power flow at point of common connection is desired , PQ control strategy is used .The simulation and analysis demonstrate that the voltage and frequency of microgrid has good stabilizing performance in the two modes .Grid-connected device with PET contributes to precise control for power flow at PCC and reducing the effect on utility during synchronization process caused by DG and load fluctuation .