Modelling and analysis of split-capacitor push-pull parallel-resonant converter in normal mode

Abstract

This paper presents a new model through which the operation of push-pull parallel resonant converters (PPRC) in normal mode can be analysed. The paper also introduces a technique whereby the converter, configured in a split-capacitor topology, can be operated either in buck or boost mode with a variable voltage gain. The three modes of operations of the converter with zero-voltage switching (ZVS) are achieved by generating a variable switching frequency through a variable phase-shift. The normal mode of operation, which is realised by switching the converter at its damped resonant frequency with zero phase-shift, is analysed in detail by deriving explicit analytical solutions for its performance and ZVS frequency. Experimental results of a 50 W prototype PPRC converter operated in the normal mode are presented and compared with simulations and theoretical results to prove the validity of both the proposed model and analysis. Impact of parasitic elements on performance has also been investigated and results indicate that they have only a little impact on the performance.