130 kHz 7.5 kW current source inverters using static induction transistors for induction heating applications

A control scheme of a high-frequency high-power current source inverters using static induction transistors is described which aims at the suppression of the surge voltage and reduction of the switching loss during the commutation of current. The inverter is operated at a leading power factor, which requires the phase angle of the output current to be adjusted to each specific load point by the controller. The stable operation is verified by the experiments under the commutation inductance 1.8 mu H, i.e., 18% reactance (130 kHz, 250 V, 30 A, base). As a result, the inverter efficiency is estimated to be 97%, excluding the loss of the drive circuit and the control circuit. >