Systems for induction heating and melting applications: a comparison of load commutated inverter

A comparative analysis of current-source and voltage-source inverters suitable for induction heating and melting applications is presented. The comparison is based on criteria such as input power factor, component ratings, maximum and minimum operating frequencies, operation under varying load conditions, inverter starting capability, and system and control simplicity. Both power supplies considered operated on the principle of load commutation. Coil parameters suitable for specifying the power supply requirements are described. The results of the comparative analysis show that the voltage-source series tuned inverter offers a better converter utilization than the current-source inverter. The voltage-source inverter´s only shortcoming is the transient flux requirement for the matching transformer. This problem is most severe at frequencies below 400 Hz and does not have much significance above 1 kHz from a practical point of view.<>