Modeling and control of a Zeta converter

A Zeta converter is a fourth-order DC-DC converter made up of two inductors and two capacitors and capable of operating in either step-up or step-down mode. Compared with other converters in the same class, such as Cuk and SEPIC converters, the Zeta converter has received the least attention, and more importantly, its dynamic modeling and control have never been reported before in the literature. This paper presents dynamic modeling and control of a Zeta converter operating in Continuous Conduction Mode (CCM). The State-Space Averaging (SSA) technique is applied to find small-signal linear dynamic model of the converter and its various transfer functions. Based on the derived control-to-output transfer function, the PWM feedback controller is designed to regulate the output voltage. Results show that the converter exhibits good performance in steady state and during a step-load change.