Non-Isolated Zeta PWM DC-DC Power Converter Analysis for CCM Including Parasitics

Abstract

This paper presents a theoretical circuit analysis for the non-isolated PWM DC-DC Zeta converter, operated at CCM (Continuous Conduction Mode) in steady-state conditions. The analysis derives the voltage and current waveforms for both current and voltages in the converter, and determines the DC voltage conversion ratio. The boundary between CCM and DCM modes is derived, as well as the expressions to determine the values of the four reactive components of the converter. The expression resulting in the maximum voltages across the MOSFET and diode are determined. The expressions giving the maximum, average and rms values of the currents associated to all the converter devices were also derived as well as the expressions of power losses due to parasitic elements in the converter circuit, and, therefore, the converter efficiency, which also included the switching losses. To validate the proposed theoretical analysis, the converter is studied both using a time-domain circuit simulation software, and building an experimental circuit utilized for practical measurements. Theoretical results were in good agreement with simulation and experimental results.

Keywords

• Zeta DC-DC converter
• dual SEPIC converter
• PWM converter
• step-down converter
• step-up converter
• non-inverting and non-isolated converter