Autonomous Power System Powered by Solar Batteries: A Case of Box Oven Heating

In this paper, we present simulation and experimental results of an autonomous power system for supplying renewable energy applications with solar batteries. This system is based on the use of a multi-branch DC/DC Boost converter, where the power switches are controlled by a digital controller that generates a PWM signal of frequency 20 kHz and duty cycle α. The electrical energy, produced by the photovoltaic (PV) panels, is stored in the batteries (24V, 520Ah) and then transferred to the load through the DC/DC converter. The experimental results obtained in the case of heating a solar cooker (oven box), heated by two thermal resistors of 15 Ω, using a DC/DC Boost converter, with three branches, show an electrical power of 300 W and duty cycle =0.7: currents of the branches of 5.3A, voltage and current of the battery of 21.82 V and 15.9 A, output of a DC/DC Boost converter of 70.4 V and 4.2 A. Under these conditions, the efficiency of the DC/DC converter is about 90 %, the energy supplied by the batteries is 558.33 Wh (i.e., 4.4 % of the battery charge), and the heating thermal resistors temperature reaches the value of 636°C after 5 minutes of heating, and the temperature inside the cooker 140°C after 40 minutes of heating. The comparison of all the results obtained with those simulated and those needed by users for cooking shows a very good agreement and consequently the validity of the functioning of the power system, of supply by solar batteries, proposed during this work.