A Single-Phase High Voltage-Gain Differential Y-Source Inverter

A three-winding coupled inductor connected as a Y-shaped impedance network has been used in dc-dc and dc-ac converters for producing a high voltage gain for renewable applications. Its versatility is further extended in this article by the proposed differential Y-source inverter with two Y-source networks. The proposed inverter is modulated by a half-sine wave, which permits only one coupled inductor and two power switches of a phase-leg to operate at a high switching frequency during each half-fundamental cycle. The outcome is significantly reduced switching losses for its semiconductors. As for leakage inductances due to imperfect coupling, their effects have been minimized by two lossless diodes, included to prevent abrupt dissipation of leakage energy. Instead, the leakage energy discharges and then recycles to the dc-link capacitors, which, in turn, help to clamp voltages across the power switches. Detailed analyses of the inverter are given in this article, supported by simulation and experimental results obtained with a 250-W prototype for boosting a 30-V dc input to a 110-V ac output.