An Efficient Resonant Pole Inverter With Reliable Elimination of Switching Loss of Main Switches

Abstract

The brief presents a novel resonant pole inverter for the efficient operation of the inverter. Its design process can be summarized briefly as follows: three sets of identical auxiliary circuits are respectively connected in parallel with each bridge arm of the three-phase hard-switching inverter and each set of auxiliary circuits only contains two auxiliary switches, two resonant capacitors and one resonant inductor; when the auxiliary circuits work, the current will flow through the antiparallel freewheeling diode of main switches periodically before main switches are switched on or off. Thus, the outstanding advantage of the novel inverter is that main switches can acquire zero-voltage switching-on and zero-current switching-off, making for more reliable elimination of switching loss. The brief elaborates each working state in a switching cycle. Experimental waveforms imply that switches can attain soft-switching. Moreover, the efficiency of the novel inverter achieves 99.1% at rated output power and the value marks an increase of 0.5 percentage points at the same rated output power, compared with the most recent topology in another literature. Thus, the novel inverter can have efficiency superiority over other soft-switching inverters when it is applied as the variable frequency power supply in the electric drive system.