Efficiency design considerations for a wide-range operated high-power soft-switching inverter

Most soft-switching inverters have been designed to eliminate the switching loss, but the traditional techniques are only effective for certain operating points. This paper explores the negative current cycle effect on zero-voltage switching type inverters and then proposes a simple timing control technique for adaptivity of operating in a wide range of source voltage and load current conditions. A three-phase coupled-magnetic type 120-kW inverter has been designed and implemented for motor drive applications. The circuit operating principle is described in detail and then verified with computer simulation. Hardware experimental results indicate a superior efficiency performance profile under different voltages and load currents