Improved MPPT short-circuit current method by a fuzzy short-circuit current estimator

Abstract

Several Maximum Power Point Tracking MPPT methods have been proposed looking for more efficient Photovoltaic (PV) system. Some of them are simple but imply low efficiency compared with more sophisticated method. The short-circuit current is a simple method to achieve the maximum power point based on the fact that the current at the maximum power point is proportional to the short circuit current. Nevertheless, the measurement of the short circuit current implies high waste of energy. In this paper a short circuit current estimator based on a Takagi-Sugeno fuzzy model of the PV array is proposed looking for overcoming the main disadvantages of the short circuit current method. The short-circuit current could be estimated under any weather condition in real time, without disconnecting the photovoltaic generator andmeasuring it. Simulation in a grid connected system shows attractive features such as high accuracy, and simple design. This method is validated by experiments using a two-stage single-phase, grid-connected inverter.