An Improved Modulation Strategy for Single-Phase Quasi-Single-Stage AC-DC Converter

An improved triple-phase-shift modulation for single-phase quasi-single-stage (Q1S) AC-DC converter is proposed to eliminate the circulating current and realize the current decouple, thus eliminating the grid side current distortion. The relationship between three phase shifts and desired transfer average current is further determined by introducing the constraint of minimum current stress. All of the theoretical analysis and the proposed ITPS modulation are validated in detail in the experimental way.