A high power density dual-buck full-bridge inverter based on carrier phase-shifted SPWM control

The Dual Buck Full-bridge Inverter (DBFBI) has great advantages in reliability and efficiency because of no shoot-through concerns, high utilization rate of DC input voltage, and optimal choice of its free-wheeling diodes. However, the four filter inductors make the inverter large and heavy, which limits its application in high power density conditions. In order to overcome the shortcoming mentioned above, a carrier phase-shifted SPWM (CPS-SPWM) control suitable for DBFBI is first proposed in this paper. First, with the CPS-SPWM control, the equivalent operating frequency of the output filter inductors is twice of the switching frequency, which can effectively reduce the size and weight of filter inductors. In addition, only two switches work in high-frequency switching state during the half line cycle of filter-inductor current, which can effectively reduce the inverter switching losses. Second, the circulating current issue introduced by this control is analyzed in detail. By separating a common filter inductor (CFI) from the four primary inductors, the circulating current losses can be effectively reduced. The design guidelines of the filter inductors are given out. Finally, the remaining four filter inductors are coupled into two coupled inductors. Experimental results verify the theoretical analysis.