A simple-control new soft-switched PWM inverter

A new soft-switching inverter is proposed which eliminates the need for any special control to insure soft-switching action. Only the comparison between a triangular carrier wave and the output three-phase sinusoidal voltages is all of the control scheme needed to obtain the PWM gating signals. As the PWM signal is exactly the same as normal hard switched inverters, the control can be realized quite easily using normal PWM ICs. A carrier frequency of 10 kHz was utilized to implement the prototype system, that works in almost no audible frequency noise, as well as the feature of less EMI operations. A significantly improved sinusoidal current waveform at the output can be obtained compared to conventional inverters even at low modulation factors.