Performance Analysis of a stand-alone photovoltaic pumping Running MPPT by Constant V/f Technology

Abstract

One of the most urgent problems that we have to face in the Saharan regions intended for agriculture is access to drinking water for irrigation, for livestock, etc. Most of the agrarian regions affected by this problem are far from electricity distribution networks. Thanks to the technological development and the emergence of several solutions, one of the solutions is to introduce photovoltaic energy as a source of electricity, and among the most widespread and successful applications is a stand-alone photovoltaic pumping system.For these systems, and to improve their operation, various control algorithms have been developed. Among these commands that we have experienced, the one required to maximize the power delivered by the photovoltaic generator (GPV) is based on the voltage feedback by fixed Vref, using the constant V/f law. The technique is open loop. By proper adjustment of the output frequency of the inverter, the efficiency of the motor can be maintained in accordance with the change of the insolation and the temperature. In this article, we propose to analyze the performance obtained with this control by varying the reference speed (or the insolation).This control technology was applied to a stand-alone photovoltaic pumping system installed in our research unit in Adrar. The experimental results obtained show that a better performance in terms of power utilization of the photovoltaic generator can be achieved thanks to this control technique, with precise sizing and in a short range of temperature variations throughout the day.