Small-signal analysis and controller design for an isolated zeta converter with high power factor correction

This paper presents the small-signal model of a proposed isolated zeta converter operating in discontinuous conduction mode (DCM). Based on the derived model, a classical controller is thus designed to tightly regulate the output voltage despite variations in the line voltage and load resistance. The experimental results validate the dynamics and performances of the proposed model. Moreover, the loss-free resistor (LFR) model is applied to verify that the isolated zeta converter exhibits a unity power factor. The operating principle and design considerations are also presented in this work. For the rectifier applications, a low total harmonic distortion (THD) of 9% in the input line current is also obtained. It meets the harmonic regulations of IEC 1000-3-2 Class D standards.