Ćuk topology based single switch single phase high power quality AC voltage controller

Abstract

A new single phase AC voltage controller based on C´uk topology is proposed. The proposed AC voltage controller has the advantage of input current shaping that provides low input current total harmonic distortion (THD) and high input power factor compared to the conventional AC voltage controllers. Moreover, only a single control switch is necessary for the AC-AC conversion compared to 6 thyristors in their conventional counterparts. The reduction in switch reduces switching loss and a simpler control circuit suffices. In the C´uk conversion, input AC current chopping at high frequencies for both positive and negative cycles provides low input current THD within IEEE 519, IEC 61000–3–2 standards and has improved the input power factor. The circuit efficiency is also acceptable for certain range of duty cycle. Positive and negative cycle C´uk conversion is performed by a single bi-directional switch and the output of two conversion is differentially connected to obtain the controllable step-up/step-down AC output voltage. The proposed circuit is investigated at low frequency switching so that it can be used in high power conversion also.