Design and implementation of MPPT controlled grid connected photovoltaic system

Abstract

This paper proposes an intelligent method for maximum power point tracking (MPPT) of a photovoltaic system under variable temperature and insolation conditions and conversion of this solar energy into stabilized sine wave having low distortion factor (DF), so that the solar energy can be supplied to grid and can operate electrical and electronic devices efficiently. For the reduction of tracking time of maximum power from photovoltaic array and to obtain stabilized sine wave with very fast rise time for voltage stability, fuzzy logic control algorithm is implemented with the embedded microcontroller for improved performance as compared to conventional techniques. The system includes a photovoltaic array; a PWM controlled DC-DC, DC-AC converters, sensor circuits and zero crossing detector (ZCD). The designed MPPT controller regulates the converter output voltage by varying modulation index of the PWM pattern using MPPT algorithm and it maximizes the output power extracted from photovoltaic array. This paper discusses the low cost implementation of MPP algorithm in a 8-bit microcontroller using the tools and techniques to generate optimized real time code in C for ATMega8 microcontroller which will demonstrate how maximum power point tracker might provide elegant and efficient solution for increasing the efficiency of a solar system and connection of the extracted energy to grid which is based on experimental results rather than on mathematical models.