State of the Art of the Medium-Voltage Power Converter Technologies for Grid Integration of Solar Photovoltaic Power Plants
More than 170 countries have already established renewable energy targets to meet their national increasing energy demand and also to keep their environment sustainable. Due to a number of features multi-megawatt photovoltaic (PV) power-plants have been becoming the first-choice for escalating and updating power-systems all-over the world. Moreover, solar PV power plant also be the first choice for meeting rapidly-growing and urgent demands, as it can be installed relatively quickly, say in 6-12 months, compared to fossil fuel-based plants that require more than 4-5 years. The traditional low-voltage (288-690 V) converter-based system requires step-up transformer and line filter to interconnect solar PV power plant with medium-voltage grids. Recently, medium-voltage converters have received a significant interest for step-up-transformer and line-filter-less direct medium-voltage grid-integration of PV power plants. This paper aims to review the necessity and technical challenges in developing medium-voltage power electronic converters including how converter circuit topologies and control techniques have affected the development of medium-voltage converters to interconnect PV power plants to medium-voltage grids directly. A comprehensive review of current research activities and possible future directions of research to develop medium-voltage converter-based reliable and cost-effective grid-integration technologies to provide for a cost-effective grid integration of solar PV power plants is presented.