Magnetically Coupled High-Voltage-Boost Split Y-Source Inverter Without Leakage-Induced Voltage Spikes

A three-winding coupled inductor, arranged as a Y-source network, has been used for voltage boosting with a standard inverter bridge and no other active switches. However, its maximum modulation and boost duty ratios are correlated with an increase of one maximum necessitating the reduction of the other. Its voltage quality and dc-bus utilization will hence deteriorate greatly at high gain. Moreover, in the presence of nonnegligible leakage, the Y-source network experiences large voltage spikes caused by unintentionally abrupt inductive current changes. Its coupling coefficient must hence be very close to unity or a snubber and always be added. To overcome these limitations, a split-Y-source inverter has been proposed, whose maximum modulation and boost duty ratios can be increased simultaneously, while using only a single-inverter bridge. It is also not burdened by inrush currents and voltage spikes and hence does not impose strict requirements on coupling and snubber. These advantages are in addition to the increased freedom of tuning two turns ratios to keep the total number of turns small, while retaining a high-voltage boost. Theoretical analyses, simulations, and experimental results have successfully verified the performance of the proposed inverter.