The output spectrum of zeta mode three-level AC/AC converter

A Zeta mode three-level AC/AC converter proposed utilizes three-level voltage in one switching period before output filter to form output sinusoid voltage, which can get a better spectrum and reduce bulk of the filter. The frequency of harmonics depends on switching period, so it can be filtered easily when the converter operates in high frequency. Compared with Two-level ac chopper, the amplitude of the first high frequency harmonic is much less when the ratio of output voltage and input is lower than 0.85. And it also can realize buck and boost output voltage. The analysis and experiment results of the prototype verify the advantage of the converter.