Analysis of Current Controlled Modulation Strategies for an AC-AC Forward Converter

Direct AC/AC converters with high-frequency isolation are becoming increasingly popular due to smaller footprint, electrical isolation and bidirectional power flow. This paper analyses current-controlled modulation strategies for an AC/AC Forward converter for low power applications. Two control strategies; Finite Control Set Model Predictive Current Control (FCS-MPCC) and Hysteresis Band Current Control (HBCC) have been studied for an AC/AC Forward converter in buck operation. Despite having a simple logic implementation, both the control methods offer high control accuracy and fast dynamic response. Simulation as well as real-time validation is further provided to assess the effectiveness of the two control techniques. The findings depict satisfactory reference current tracking characteristics while keeping the total harmonic distortion under 5 % through the aid of small filter elements.