Single Stage OLTC Based High Resolution Multilevel Inverter for Solar PV Application

Abstract

Designing grid-connected solar photovoltaic (PV) systems involves addressing numerous challenges that arise from fluctuating solar generation levels. The converter utilisation for a single stage inverter in a grid-connected photovoltaic system is less than 50%. However, DC-DC converters in two stage configurations can effectively double utilization by enhancing efficiency and optimizing power output. However, it increases the cost of overall system. A solution is proposed in this paper in which converter utilization can be increased up to 80% using single stage inverter. A line transformer is required in high power medium voltage applications in order to raise the output voltage. To improve the inverter's utilisation, on-line tap change can be done on the transformer's secondary side. Hence, as per change in solar insolation this converter will evacuate power as per tap management. Furthermore, the converter will consistently remain connected to the grid under all circumstances. Double LDN based high resolution multilevel inverter is used to verify the concept. The proposed idea is simulated in MATLAB.