Optimization Strategy of Reduction of Switching Times in Rectifier Stage Based on Power Electronic Transformer

Abstract

The control strategies of conventional power electronic transformer are mostly double closed-loop control based on dq coordinate decomposition, and the control strategy is complex. Based on the analysis of the topology of single phase cascaded power electronic transformer, this paper takes the transformer primary rectifier as the typical object. According to the multilevel synthesis strategy, an improved ladder wave level control strategy is proposed and the quasi-proportional resonance is proposed. The simulation results show that the new control strategy can verify the proposed scheme by ensuring that the total voltage of the rectifier stage is maintained at a given value, the voltage of each module rectified voltage is approximately equal, and the switching frequency of the switching device is greatly reduced, and power factor of grid approaches 1.