POSITION CONTROL OF SOLAR PANNEL
Photovoltaic systems normally use a maximum power point tracking (MPPT) technique to continuously deliver the highest possible power to the load irrespective of the temperature and irradiation conditions and of the load electrical characteristics. 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 voltage is used to directly control the position of solar panel, thus reducing the complexity of the system. A simple method of tracking the maximum power points (MPP’s) and forcing the system to operate close to these points is presented. This paper details the proposed work to design the solar tracking system based around the microcontroller programmable IC. The solar panel is in the form of array of photovoltaic cells. The operation of the solar panel is actuated by means of the final control element (FCE). The FCE used is stepper motor. For the optimum utilization of solar energy the position of solar panel in the form of photovoltaic array is controlled in accordance with the position of optical electronic sensors located at particular angle of elevation of light rays with respect to ground.
The physical model consists of solar panel in the form of photovoltaic cells; to which the stepper motor with its extended shaft is fabricated. The minimum necessary hardware interfacing circuit associated with microcontroller and the stepper motor is designed and fabricated. The control functions are implemented using 8051Microcontroller based hardware and software. The proposed model resembles the features of solar tracking system, which can be used in usual practice. The experimental results show that the use of the proposed MPPT control increases the PV output power by as much as 10-15% and hence the resulting system has improved high-efficiency, lower cost and can be easily modified to handle more energy sources.