Design and Analysis of Microcontroller-Based, Maximum Power Point Tracker for Photovoltaic Power Systems

Maximum power point tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic array output power, irrespective of the temperature and irradiation conditions and of the load electrical characteristics. These techniques vary in many aspects as simplicity, digital or analogical implementation, sensor required, convergence speed, and range of effectiveness, implementation hardware, popularity, and cost and in other aspects. A new MPPT system has been developed, consisting of a Buck-type dc/dc converter, which is controlled by a microcontroller-based unit. The main difference between the method used in the proposed MPPT system and other techniques used in the past is that the PV array output power is used to directly control the dc/dc converter, thus reducing the complexity of the system. The resulting system has high-efficiency, lower-cost and can be easily modified to handle more energy sources. This paper describes the development of prototype model based on incremental conductance algorithm in the laboratory, the necessary interface circuits and software control algorithm.