A Maximum Power Point Tracking VRLA Battery Charger Based on Modified Perturb and Observe Technique

This paper proposes a modified Perturb and Observe (P&O) algorithm for maximum power point tracking (MPPT) from a solar module to charge a VRLA (valve-regulated lead-acid) battery in an optimal fashion. The battery charging system has a capability to maximize the input power to the battery under variable insolation and temperature conditions. Generally, in battery charging system, the battery current and voltage are required to monitor, for the sake of battery protection or state-of-charge (SOC) estimation or to implement different charge control techniques. In this study, the P&O technique is implemented by using the same battery voltage and current sensor with an additional photovoltaic (PV) voltage sensor. A theoretical analysis of the proposed method is described, and its feasibility is also tested by experimental results.