A novel single-phase separated-SPWM controlled inverter with a high frequency link

A novel single-phase inverter topology with a high frequency (HF) link is proposed in this paper, and a new control strategy is presented accordingly. The function of the two forward converters of the primary part is to chop the DC input into two groups of HF voltage pulse trains, but the forward converters are controlled by a separated-SPWM (sinusoidal PWM) signal, thus the maximum operation duty cycle of SPWM signal can be set to be higher than 0.5 with low voltage stresses. The secondary part mainly consists of four rectifier diodes, two main switches and two energy feedback shunt circuits. Because of the existence of two energy feedback shunt circuits the inherent voltage surge problem is solved. Because the main switches of the secondary only conduct voltage pulses, the soft switching can naturally be realized. Experimental results show that the proposed circuit is feasible and can be realized easily