Dual Mode Controller-Based Solar Photovoltaic Simulator for True PV Characteristics

Abstract

Integration of solar photovoltaic (PV) panels with existing utilities requires effectively controlled converters. While developing and testing such converters, it is difficult to test them with actually installed PV panels owing to unavailability of practical onsite conditions for all the time. For such cases, PV simulators are preferred, which are required to exhibit PV system behavior under working conditions without the use of real outdoor installation. This reduces the time and cost of experimentation. In this paper, a real-time PV simulator based on a dc-dc buck converter is investigated to obtain true PV characteristics. The practical difficulty with PV simulators is that they often get oscillations in the constant current region or constant voltage region of PV characteristics, particularly when the controller is designed using a low-cost digital controller. This paper introduces a novel hysteresis controller to ensure effective operation in both these regions. This dual control strategy ensures effective control in both regions and provides smooth trajectories as per mathematical model or lookup table to mimic any PV characteristics under various temperatures and insolations with the use of the low-cost digital controller. The hardware prototype is constructed with the digital signal controller to demonstrate the efficacy of the proposed simulator.