Three phase high step-up single-stage flyback converter with no electrolytic capacitor

This paper introduces a novel three phase high step-up single-stage flyback converter with no electrolytic capacitor for small-scaled wind generation application. The proposed converter combines flyback cell and three-phase single-switched boost converter in order to achieve high step-up voltage gain at low input voltage and high efficiency at rated input voltage. The circuit is operating in discontinuous current mode (DCM), and thereby power factor correction (PFC) is also achieved. Since no electrolytic capacitor with large capacitance is employed, weak power can be collected at extremely low input voltage. At last, a prototype of 300W is built, operating with input phase voltage of 36.3Vac and output voltage of 365.5Vdc at rated, and its efficiency is 85% with the total harmonic distortion (THD) being less than 10%.