Topology and control strategy of UPQC based on High Frequency Isolation DC/DC converter

The traditional unified power quality controller (UPQC) topology based on modular cascade structure usually requires line transformer to effectively isolate the DC bus of each subunit when used in high voltage applications. The line transformer may bring various problems such as increased cost, magnetic saturation, surge current, phase shift and so on. In this paper, a new type of UPQC based on DC side high frequency isolation DC/DC converter is proposed. The new topology avoids the use of line frequency transformer, so it can reduce the size and lower the cost. In this paper, the topology and control strategy are proposed and the simulation results are presented to verify the effectiveness and the performance of the proposed method.