| Abstract |
For industrial induction heating applications, requiring frequencies greater than 100 kHz, triode valve oscillators power supplies have been used. For some years, studies have been made to replace these oscillators with transistorized power supplies. In the range of power of some kW and frequency greater than 200 kHz, power MOSFET transistors are well suitable. These transistors require low drive power and paralleling for higher power is easy. In this paper, a current source inverter (2 kW, 200 kHz) with power MOSFETS has been built. The load is a parallel resonant one. A phase locked loop circuit has been designed to maintain switching frequency nearer the load resonant frequency, and the load current in advance of phase with the voltage. So, transistor switching losses are reduced to the minimum and no snubber circuits are required. |
