Fuzzy Controller based Closed Loop Control for Single Stage Single Phase Grid Integrated PV System with Novel Configuration of 7 Level Hybrid Inverter

Abstract

Grid integrated renewable energy sources are greatly benefiting from the use of multilevel inverters, as they inject less total harmonic distortion (THD) and improve the quality of inverter voltage. However, these inverters face challenges due to their high number of switches and complex control. Therefore, it is necessary to explore new configurations with simpler and more effective control methods. In addition, Photovoltaic (PV) systems are being installed in numerous apartments and houses, typically connected to a single phase utility grid. It is crucial to ensure power quality through the use of an inverter connected between the PV system and the utility grid, controlled by the inverter itself. Since PV systems exhibit non-linear behavior, a DC to DC converter is required, along with an appropriate algorithm to maximize power output. However, the inclusion of an additional DC to DC converter can increase the size, cost, and complexity of the system. As a result, single stage grid connected systems have gained popularity for low power applications. Furthermore, the use of a Fuzzy controller has shown superior performance compared to PI controllers, thanks to its ability to adjust gains based on changes in solar irradiance and load. Therefore, this paper introduces a new configuration of a 7 level inverter for single phase single stage grid connected PV systems, incorporating a Fuzzy controller for control. This new configuration only consists of seven switches, making it more streamlined. The paper includes extensive results to validate the effectiveness of the proposed methodology.