Class D Series Resonant Inverter with PDM Scheme For Induction Heating Application

This paper proposes a unique topology of Class D series resonant inverter with output power control schemes for Induction Heating (IH) application. The main aim of this work is to reduce the steady state error so as to get better performance for induction heating applications under varying load conditions. The power control strategy allows the class D series resonant inverter to operate nearly at the resonance frequency and enhances the power quality of inverter output power waveform. The class D series resonant inverter here employs constant frequency Pulse Density Modulation (PDM) scheme to reduce the switching losses. It also compares the performance of closed loop output power control using conventional PID controller and Load Adaptive Fuzzy logic controller (LAFLC) for reducing steady state error. To verify the results, the proposed Class D inverter system is designed and simulated using MATLAB/SIMULINK simulation tool. The PDM method is implemented by using the PIC16F84A microcontroller. The proposed system is simulated and validated by experiments in the laboratory.