Isolated MPPT, CC, CV Solar Battery Charger Design and Application

Abstract

With the rapid increase in energy consumption, the production and storage of solar energy from renewable energy sources has become a important subject. The problem of low-efficiency energy transfer from the solar panel has been overcome with the maximum power point tracking (MPPT) method and algorithms. In this study, an isolated MPPT, constant current (CC), constant voltage (CV) solar battery charging circuit with perturb and observe (P&O) algorithm is proposed. Three different modes (MPPT, CC, CV) work together in the proposed solar battery charging circuit. Panel and battery current-voltage values are constantly measured by the microcontroller, and according to these values, the algorithm determines which mode the circuit will operate in. The converter is constantly trying to transfer maximum power to the battery in every mode it operates. The CC and CV modes in the converter also try to achieve maximum power continuously and quickly, and their algorithms are much easier and simpler than traditional PID controls. Another advantage of the algorithm is that it has a direct transition between modes, thanks to its fast response in terms of efficiency and protection. After changing the duty (D) in any mode, it is checked whether it is necessary to switch to the other two modes without returning to the beginning. Theoretical analyzes have been verified by the application of a battery charging circuit with 120 W output power, 12 V output voltage and 10 A output current.