A DELTA-CONFIGURED AUXILIARY RESONANT SNUBBER INVERTER

A delta (Delta)-configured auxiliary resonant snubber inverter is deve loped to overcome the voltage floating problem in a wye (Y)-configured resonant snubber inverter, The proposed inverter is to connect auxili ary resonant branches between phase outputs to avoid a floating point voltage which may cause overvoltage failure of the auxiliary switches, Each auxiliary branch consists of a resonant inductor and a reverse b locking auxiliary switch, Instead of using an antiparalleled diode to allow resonant current to how in the reverse direction, as in the Y-co nfigured version, the resonant branch in the Delta-configured version must block the negative voltage, typically, done by a series diode, Th is paper shows single-phase and three-phase versions of Delta-configur ed resonant snubber inverters and describes in detail the operating pr inciple of a single-phase version, The extended three-phase version is proposed with nonadjacent state space vector modulation, For hardware implementation, a single-phase 1-kW unit and a three-phase 100-kW uni t were built to prove the concept. Experimental results show the super iority of the proposed topology.