J. Basic. Appl. Sci. Res., 3(9)456-466, 2013 © 2013, TextRoad Publication ISSN 2090-4304 Journal of Basic and Applied Scientific Research www.textroad.com Corresponding Author: Muhammad Asghar Khan, COMSATS Institute of IT, Islamabad, Email: engr.asgharktk@yahoo.com Improvement in Perturb and Observe Method for Maximum Power Point Tracking of PV Panel M. A. Khan, A. Mahmood, M. Arif, M. N. Ullah, I. Khan, M. S. Hassan, A. Zafar, Z. A. Khan* COMSATS Institute of Information Technology, Islamabad,Pakistan. *Internetworking Program, Faculty of Engineering, Dalhousie University, Halifax, Canada. ABSTRACT This paper presents a continuous maximum power point tracking algorithm to get better the effectiveness of the photovoltaic panel by capturing the maximum output power from it and ensure optimum power availability to the load. As the incident solar radiation and the temperature of the panel changes continuously, in such an unpredictable parameters changing situation, the decision of locating the maximum power point is not always tedious but also a wearisome job. Up till now several MPPT techniques have been developed in different ways to resolve the problem. In these the most commonly used techniques are Perturb & Observe method, Variable Inductor method, Incremental Conductance method, and Parasitic Capacitance method for a large Photovoltaic array. In Perturb and observe method, we can improve the efficiency of PV panel through variation in duty cycle using a special control mechanism. Also we present some simulation results of PV panel for a specific location with all parameters known. Finally we will show that the efficiency of Perturb and Observe method can be increased significantly using our proposed technique. KEYWORDS: Photovoltaic (PV) panel, Maximum power point tracking (MPPT), Perturb and Observe (P & O) method, incident solar radiation (INSOLATION), DC-DC converter I. INTRODUCTION A day will soon dawn when earth will be deprived of fossil fuels need of the hour is to surge their alternatives, every one of us is looking forward to some reliable energy reservoir, the sources that can prove themselves not only long-lasting but also environment friendly. What can be better than those elements that are widely distributed on this planet i.e. sun, wind, rivers and geothermal power points, etc. Among all these the solar energy is the most attractive and widely distributed. The energy from sun is being used and utilized by human beings and all other creatures since time unknown. It is an extremely clean, endurable and renewable energy source, which we can exploit in the manufacturing of a solar lightning, heating, and solar cooling appliances etc. A photovoltaic cell is an electrical piece of equipment that transforms the solar energy directly into an electrical energy. It is called an electrical device, in the since because its electrical parametric quantities e.g. voltage, current and resistance varies whenever light rays are incident on it. Operating the PV panel at the maximum power point increases its efficiency by getting the maximum available power under changing weather conditions as in [11]. The maximum power point tracking (MPPT) is fundamentally an impedance tuning issue. The basic requirement is, to change the solar panel input resistance by varying the duty cycle of a DC- DC converter to match with the load resistance. The perturb and observe (P&O) is a straightforward and less expensive technique for locating the maximum power point (MPP). However major flaw of this technique is that, at nearly constant irradiation level, the operating point fluctuates around the MPP which reduces its efficiency. The second drawback is that the P&O technique can puzzles during the periods characterized by continuously varying weather circumstances as in [1]. We can mitigate the drawbacks of perturb and observe method by means of a DC to DC converter capable of having a controlled changeable duty cycle. At the steady state during the oscillation period we increases the duty cycle (D) which reduces the value of ∆P gradually and finally it reaches zero as explained in the flow chart of Fig. 8. The point at which ∆P becomes zero is the MPP. This technique is also helpful in mitigating the second drawback i.e. during changing weather condition the algorithm will locate the MPP more quickly. 456