A new control strategy of active clamped flyback inverter for a photovoltaic AC module system

In this paper, a new control strategy of an active clamped flyback inverter for a photovoltaic AC module system is proposed. In the flyback inverter, a voltage spike across a main switch is generated from a resonance between a leakage inductance and an output capacitance across the main switch. For reducing the voltage spike of the main switch, a snubber circuit is used. In case of the active clamp technique, the circuit has a conduction loss, switching loss and gate drive loss because the switch is turned on and off with a hard switching. Therefore, a consideration reducing the losses of the active clamp circuit is required. If the new control strategy is used, the active clamp switch is not operated during a low voltage in an utility line period. Therefore, the losses of the active clamp circuit can be reduced. In order to verify these, theoretical analysis and simulations are performed.