Design Analysis of Full-Bridge Parallel Resonant Inverter for Induction Heating Application Using Pulse Density Modulation Technique

In this work, full bridge parallel resonant inverter (FBPRI) using pulse density modulation (PDM) technique has been proposed for industrial induction heating application like brazing, welding, melting of iron etc. There are so many techniques that have been developed for FBPRI to control the output power in IH application. But none of them are able to maintain resonating and ZVS/ZCS condition under a different operating condition which is a key feature of resonant converters. Due to this, efficiency and performance of IH system are degraded. Keeping this disadvantage, a pulse density modulation (PDM) technique has been proposed in this work for FBPRI to achieve better efficiency and performance of the classical IH system. This proposed technique ensures the ZVS/ZCS condition which reduces the switching losses. The proposed control method/technique is described in detail and it is validated through PSIM simulation at a frequency of 47 KHz.