Comparison of PWM AC chopper topologies

In this paper, a commonly reported single-phase four-switch AC chopper topology is compared with a six-switch topology in terms of the total harmonic distortion (THD) of the input current, power factor (PF), commutation behavior, robustness and efficiency. Working principles of both topologies are presented along with simulation results. Based on a comparison of the findings, the four-switch topology is found to be better choice for the given application. Thus, the implementation of a four-switch topology is carried out at a power level of 10 kW. Experimental evaluation is carried out in order to verify the suitability of the circuit for the intended application. The experimental setup validates the findings of the simulations. Thus, the proposed approach is a practical way to improve input current THD and PF compared to thyristor choppers.