Analysis and optimisation of a flyback convertor with a nondissipative snubber

The paper explores the optimum design of a nondissipative snubber employed in a PWM-controlled flyback power convertor. A simple but efficient transistor model was used to evaluate the switching loss. An optimum snubber capacitor value was defined, providing minimum total losses in the snubber network. Owing to the snubber, the operating frequency region of the IGBT transistor used was significantly extended. A 850 W convertor prototype for microwave heating was built and tested to verify the theoretical results.