Actual efficiency and electromagnetic noises evaluations of a single inductor type resonant AC link snubber-assisted three-phase soft-switching inverter

In recent years, it has been more important power conversion technology for implementing the downsizing and low electromagnetic noise, high performance and high efficiency in order to achieve high frequency pulse modulation-based switching of the power semiconductor devices in power conversion circuits and systems with a great advance of the power semiconductor switching devices. In general, high frequency switching-based pulse width modulation of the power semiconductor devices in the inverter and converter produces some significant problems such as increase of switching power losses and EMI/RFI noises, leak current generation related to a high dv/dt and electrical insulation breakdown of reactor and transformer due to a high di/dt. In order to overcome these problems, soft switching power conversion circuit technologies are able to give effective solutions from a practical point of view. In this paper, a novel prototype of the resonant AC link snubber-assisted inverter that the auxiliary resonant commutation circuits are simply connected in parallel with the three-phase AC load of the three-phase voltage source inverter is presented to achieve the zero voltage soft switching PWM or pulse modulated zero voltage soft-switching inverter or rectifier, and operation mode and the sinewave modulation method of an active resonant AC link snubber circuit is described, and the performance evaluations such as output line-to-line voltage waveforms, actual power conversion efficiency, electromagnetic conductive and radiative noises of this resonant snubber-assisted voltage source soft-switching inverter circuit are basically evaluated and discussed as compared with those of three-phase hard-switching inverter from an experimental point of view.