Three-phase zero-current-transition (ZCT) inverters and rectifiers with three auxiliary switches
Zero current transition (ZCT) topologies are presented for three-phase inverters and rectifiers. Such devices are used for example in AC adjustable speed drives for so-called zero-emission vehicles (i.e., electric and hybrid combustion/electric automobiles). Compared to existing three-phase ZCT techniques, the number of auxiliary switches is reduced from six to three, while not altering the necessary device rating. Correspondingly, the number of gate-drivers for the auxiliary switches is also reduced to three. Meanwhile, the merits of the existing three-phase ZCT techniques are still retained, i.e., all the main switches and the auxiliary switches are turned on and turned off under zero-current conditions, and the independent commutation for each main switch is achieved. The desired soft-switching features are achieved. Therefore, this invention will contribute to more cost-effective, reliable, and efficient high-performance three-phase inverters and rectifiers.