Dynamic 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. The State-Space Averaging (SSA) technique is applied to find small-signal linear dynamic model of the converter, whereby various transfer functions of the converter can be determined. Based on the control-to-output transfer function, the compensator in PWM feedback loop can be designed to regulate the output voltage. Simulation results show that the converter exhibits good performance during a start-up and step load change.