Large scale Photovoltaic structures with medium-frequency isolation

Abstract

Energy generation via Photovoltaic (PV) technologies has increased in the last years. Large scale PV generation have attracted interest among countries due to low operation cost and wide PV resource disposition. However, some operative challenges in large scale PV plants had been detected: power imbalance, low power quality in terms of total harmonic distortion (THD), power factor and conversion efficiency, can be mentioned. This paper is focused on topologies featuring medium-frequency (MF) isolation and presents a review of different approaches to solve those operative issues. Medium-frequency isolation reduces current and improves efficiency, reliability, and provides isolated DC sources for power electronics converters, and can replace bulky low-frequency transformers, thus reducing PV system volume. Simulations of three-phase 10 kW PV systems are presented: MF link PV system, Delta inverter and a PV system based on a matrix converter.