Virtual Investigations of a Stand-Alone Photovoltaic System with Supercapacitor Bank Used to Power an Irrigation System

The paper presents virtual investigation studies of a stand-alone Photovoltaic (PV) system with a supercapacitor bank, used for powering an irrigation system. It powers two water pumps of 200W each, with input power varying from 50W to 350W. An algorithm was developed for controlling the charging and discharging of supercapacitors, in order to optimize the operation of the water pumps. Next, an equivalent electric circuit is created, and SPICE simulations are performed in the Micro-Cap environment. Two scenarios are investigated, using 300F and 250F supercapacitor banks, rated at 27V and 32V, respectively. Furthermore, for each scenario, the capacitors charging/discharging currents during the different operation regimes are assessed. The results showed that the maximal currents during the worst-case scenarios are within (12.3-16.6) A. Another important parameter that was investigated is the minimum operating time of the pumps during “sudden absence of power” for the two scenarios -59s and 141s, respectively.