Soft switching flyback inverter for photovoltaic AC module applications

The soft switching flyback inverters still cannot provide high efficiency and low output current total harmonic distortion (THD) in all load ranges. Therefore, a new flyback inverter with soft switching for photovoltaic AC module applications is presented in this study. The introduced inverter is simple and a small auxiliary circuit is added to the conventional topology of the flyback inverter. Since the primary current of the transformer is not affected by the auxiliary branch, the output current THD does not increase. In addition, all of the high-frequency switches of the proposed topology are switched under soft switching condition, which allows high-switching frequency. Hence, high efficiency, as well as compact design, can be achieved in the proposed inverter. Moreover, the voltage overshoot of the main switch during the turn-off process is limited. This effect decreases the conduction losses because the lower voltage rating switch can be used. Furthermore, a new control method is presented, which provides high efficiency in all load ranges. The operations of the introduced flyback inverter and component selection have been discussed in detail. The performance of the proposed inverter with the auxiliary circuit and corresponding controllers are validated with the help of experimental results.