A power-control scheme with constant switching frequency in class-D inverter for induction-heating jar application

In this paper, a simple power-control scheme for a constant-frequency class-D inverter with variable duty cycle at constant frequency is proposed. It is more suitable and acceptable for high-frequency induction-heating (111) jar applications. The proposed control scheme has the advantages of not only wide power-regulation range but also ease of output-power control. In addition, it can achieve stable and efficient zero-voltage switching in the whole load range. The control principles of the proposed method are described in detail, and the validity is verified through the simulated and experimental results on the 42.8-kHz insulated gate bipolar transistor for an IH rated on 1.6 kW with constant-frequency variable power.