Performance Evaluation of Step-Up/Down Partial Power Converters Based on Current-Fed DC-DC Topologies

This paper presents several topologies of the series-connected partial power converters based on current-fed full-bridge and push-pull topologies. It provides a detailed comparison of the voltage and current stresses of the components and analyzes the controllability of the corresponding converters near zero partiality. The analysis is performed for the same operating conditions to define performance traits of the baseline current-fed topologies in the partial power conversion systems. The experimental study corroborates the theoretical results. An application-agnostic comparative assessment for these topologies is provided. Their performance in PV applications was demonstrated as a case study. All the results are obtained for converter operation in a residential dc microgrid with an operating voltage of 350 V and considering PV string voltage range of 350 ± 50 V, which results in the maximum partiality of 12.5%.

I. Introduction

Demands imposed on modern electric energy generation and distribution networks have sped up the development of power electronic systems [1]. Due to the widespread adoption of domestic solar photovoltaic (PV) and wind power systems, the technology of residential battery energy storage systems has attained the most interest among the rest [2], [3]. Power converters interface these energy generation and storage units, making them especially important in dc microgrids [4]. These converters can be broadly categorized into voltage-fed, impedance-source, and current-fed (CF) converters [5], [6], [7]. Recently, current-fed converters have been introduced because of their inherent benefits, such as soft switching [8], [9], resonant switching [10], use of parasitic resonance [11], and active snubber [12].