A novel control strategy of an active clamped flyback inverter with synchronous rectifier for a photovoltaic AC module system

In this paper, a novel control scheme of an active clamped flyback inverter with synchronous rectifier for a photovoltaic AC module system is presented. The synchronous rectifier (SR) is used on the transformer secondary side to reduce a conduction loss and to improve efficiency. Compared with an rectifier diode, the higher voltage rating switch can be used as the SR. And R
_d(on)
of an anti-parallel diode of the switch is lower than R
_d(on)
of the rectifier diode. After comparing the switch losses and the anti-parallel diode losses of the SR, the switch is turned on when the switch losses are lower. By adjusting the proposed control method, the operating region of the SR according to the grid phase is determined. A flow chart and operating region of the SR according to an output power have been presented in detail. The effectiveness of the proposed control strategy is validated thorough PSIM simulation results.