Mixed PWM for Dead-Time Elimination and Compensation in a Grid-Tied Inverter

Numerous studies have been carried out to compensate or eliminate the dead-time effect. This paper analyzes the limitations of the previous compensation or elimination schemes. Then, a novel mixed pulsewidth-modulation scheme for dead-time elimination and compensation is proposed for the grid-tied inverter. The proposed scheme implements the dead-time elimination in most of the grid current fundamental period but switches to the conventional dead-time compensation around the zero-crossing point. In this way, a safe and efficient dead-time effect elimination method is achieved. Furthermore, this paper proposes to determine the switching point and the compensation direction by the grid current modulation function. Experimental results are given to demonstrate the validity and features of the proposed method.