Maximum Power Point Tracker Applied in Batteries Charging with Photovoltaic Panels

Recently, the concern for environmental issue has been rising in the world such as global warming by exhausting carbon dioxide (CO2) and breaking of ozone layer by freon gas. On December 1997, during the Kyoto Conference on Climate Change (COP3), it was agreed that by the year 2012 the developed countries would reduce at least 5% of the green house gases compared with year 1990 (Riza et al., 2003). Moreover, the global energy shortage and the need for sustainable energy systems enforce the development of power supply structures that are based mainly on renewable resources. Photovoltaic (PV) system is gaining increased importance as a renewable source due to advantages such as the absence of fuel cost, little maintenance and no noise and wear due to the absence of moving parts. But there are still two principal barriers to the use of photovoltaic systems: the high installation cost and the low energy conversion efficiency. A PV panel is a non-linear power source, i.e. its output current and voltage (power) depends on the terminal operating point. The maximum power generated by the PV panel changes with the intensity of the solar radiation and the operating temperature. To increase the ratio output power/cost of the installation it is important that PV panel operates in the maximum output power point (MPP). This chapter describes a lead acid battery charger using a PV panel with high efficiency. It starts by introducing the PV panel characteristics and describing the DC/DC converter need to implement the MPPT algorithm. This is the most important part of this work and shows how to charge and discharge correctly a lead acid battery. The developed prototype uses the perturbation and observation (P&O) MPPT algorithm with the objective to maximize energy storage in the battery. The MPPT algorithm is integrated in one of the main stages of charge of lead-acid batteries making an autonomous and intelligent system that can be used to feed any remote load or small application. It is very important to respect the correct battery charge curves because it will prolong its correct operation and live (Vieira and Mota, 2009). The P&O MPPT algorithm is used to control the maximum transfer power from a PV panel to the battery. This algorithm is executed by a microcontroller using the PV voltage and