In induction heating (IH) system, it has been observed that, due to load variation, the effective voltage across the load changes. Owing to this, resonance condition is affected and also the desired output power across the load starts to vary. It is essential to maintain resonance condition and constant output power to IH load in order to enhance its heating quality. Regarding this requirement, this paper approaches a design of fuzzy logic controller (FLC) using pulse density modulation (PDM) technique for full bridge series resonant inverter (FB-SRI) to maintain constant output power irrespective of load variation for IH applications. The proposed technique has been validated in MATLAB/Simulink environment under different load parameters. The results are obtained through simulation and this shows the uniqueness of the FLC using PDM to maintain the constant output power across the load.

Keywords: Induction heating (IH), Full bridge series resonant inverter (FB-SRI), Fuzzy logic, Pulse density modulation (PDM)