A Corona Discharge Treater using a 30kHz 5kW IGBT Inverter.

Corona discharge treaters have been used to treat surface of polyethylene films and to improve affinity for inks. The features of a resonant inverter system using IGBT's for corona discharge treaters developed in this paper are as follows. (1) No external reactors or capacitors are necessary because a series resonant circuit is composed of a leakage inductor of a step-up transformer and a capacitor between discharge electrodes of the treater. (2) A three-phase diode rectifier can be used because the output power is controlled by adjusting output power factor of the inverter. (3) A capacitor is connected between a collector and emitter of IGBT's to reduce switching losses.An optimal design of the capacitor is done by utilizing an analog circuit simulator. The authors propose an equivalent circuit of the IGBT because there may be no exact IGBT model for analog circuit simulators. The validity of the equivalent circuit is verified by comparing experimental results with simulated ones. As a result, it is shown experimentally that the optimal capacitor, which is determined by the simulation developed in this papaer, leading to higher efficiency.