Zeta Mode Three-level AC/AC Converter

Abstract

A Zeta mode three-level AC/AC converter is proposed, the converter is available in high input voltages as well as in high power applications, and it also intended for use in applications where a sinusoidal output voltage of high quality is needed. It realizes the three-level voltage waveforms before output filter, which can get a better spectrum and reduce bulk of the filter. Compared with non-isolation and low or middle frequency isolation AC-DC-AC converter, it is single stage. And compared with Buck non-isolation AC/AC converter, it can realize buck and boost output voltage. The voltage stresses of its power switches are lower than two-level Zeta AC/AC converter. A non-complementary control strategy the converter adopts can make the converter switch smoothly between different operation modes without any voltage spike. It also realizes the non-complementary control in bidirectional power flows, so the converter is suitable to different kinds of loads.