Comparison of swept frequency and phase shift control for forced commutated series resonant induction heating converters

The choice of a circuit topology and switching strategy for a specific induction heating application will to a large extent depend on the requirements for the application and the variation in the parameters of the load during heating. In this paper the forced commutated swept frequency and the forced commutated phase shift control switching strategies for the voltage fed, full-bridge, series resonant circuit topology are compared. This is done by means of a case study for a constant load current control loop and the results are obtained with an analytical model. The phase shift control switching strategy proved to be more efficient regarding semiconductor ratings.