High Efficiency Photovoltaic Power Controller Using Mppt and Buck Boost Converter

The maximum power point tracking (MPPT) is used in photovoltaic system to maximize the photovoltaic array output power , irrespective of temperature , IR radiation, conditions and electrical characteristics of the load. A new MPPT system is developed consisting of DC to DC converter, which is controlled by microcontroller based unit. There are two charging stages for the proposed PV charger. At the beginning of charging process, a continuous MPPT charging scheme is adopted. When the State of Charge (SOC) of battery reaches the given condition. a pulse current charging scheme with adaptive rest period applied to obtain an average charging current with an exponential profile. During the charging period MPPT function is retained to achieve high charging efficiency. Over charging of the battery can be avoided using the pulse charging scheme with adaptive rest period. The main difference between the method used in the MPPT system and other techniques used in the past is that the PV array output power is used to directly control the DC to DC converter, thus reducing the complexity of the system . In addition, we attempt to design the MPPT by using the algorithm of a selected MPPT method which is “Perturb and Observe “and implement it by using a DC– DC Converter. We have found various types of DC-DC converters .Among them we have selected the most suitable converter which is “BUCK-BOOST” converter , for our desing.PV generation system generally use a microcontroller based charge controller connected to a battery and the load. A charge controller is used to maintain proper charging voltage on the batteries. As the input voltage from the solar array, the charge controller regulates the charge to the batteries preventing any overcharging. So a good, solid and reliable PV charge controller is a key component of any PV battery charging system to achieve systems maximum efficiency. Whereas microcontroller based designs are able to provide more intelligent control and thus increases the efficiency of the system.