New power supply topologies enabling high performance induction heating by using MERS

Conventional power supply for induction heating has many limitations about controllability. The operating frequency can not be changed independently due to the use of resonant capacitors. The current amplitude can not be controlled by the inverter with fundamental frequency switching (FFS) since the duty ratio control is not available for amplitude control with soft-switching operation; therefore, an additional stage for the dc voltage or current control is needed. This paper proposes the use of a reactive power compensator named MERS with the inverter, which adds the independent controllability of frequency and current.