Single switch quasi-resonant inverter on Silicon Carbide with regenerative snubber for induction heating appliances

One of the main problems of power inverters designed for induction heating home appliances is the broad variance of possible loads. One-switch resonant inverters for induction heating are designed to increased power as frequency decreases; duty cycle is later computed to achieve Zero Voltage Switching (ZVS) condition. To further reduce the output power, over minimum at obtained at Zero Voltage and Derivate Switching (ZVDS), and allow independent control of power with frequency, sophisticated control techniques need to be applied, but depending on load, non-ZVS switching conditions may occur therefore degrading the performance and efficiency. This paper proposes a regenerative inductive snubber capable of reduce transistor losses in non-ZVS conditions. In this proposal, the snubber is actually a minor part of the induction coil. Therefore, the power delivered to the snubber is part of the output. Experimental results show good agreement with the theoretical equations.