A 5 kW utility-interactive inverter operating at high frequency and using zero current turn off COMFET switches

The design of a 5 kW utility-interactive high-performance series resonant inverter is described. The inverter operates in an inaudible frequency range (20 kHz-100 kHz) and in the quasi-resonant mode. The results of an analytical study of the inverter show that, in this mode of operation, the inverter output characteristics are of the current-source type independent of the output voltage of the AC utility. The inverter uses turn-on controllable COMFET switches in the soft commutation mode and does not require snubber circuits. This converter combines the advantages of working at high frequency (less weight, small reactive filters, and absence of low-frequency transformer) and of using resonant links that allow the use of zero-current turn-off switches. Some of the experimental and simulation results obtained on a 2.5 kW-capacity laboratory prototype are presented.<>