Improved Three Switch-Active Clamp Forward Converter With Low Switching and Conduction Losses

The improved three switch-active clamp forward (3S-ACF) converter is proposed in this paper. The proposed converter has minimized the switching loss on all switches of the conventional 3S-ACF converter by simply changing the gate control method without any additional components. Moreover, the modified gate control enables peak and average currents on the clamp diode to be reduced. Though, all switches of the proposed converter have low-voltage stress similarly to those of the conventional 3S-ACF converter. Consequently, the proposed converter can achieve a high efficiency without any additional components. To confirm the operation, features, and validity of the proposed converter, a 180–288  V dc input and 12 V/550 W output laboratory prototype is built and tested.