INTERNATIONAL JOURNAL of RENEWABLE ENERGY RESEARCH S. Hesari , Vol.6, No.4, 2016 Design and Implementation of Maximum Solar Power Tracking System Using Photovoltaic Panels Sadegh Hesari * Young Researcher and Elite Club, Bojnourd Branch , Islamic Azad University , Bojnourd, Iran (Hesari.sadegh@yahoo.com) ‡ Corresponding Author; Sadegh Hesari, Tel: +98 9152549200, Hesari.sadegh@yahoo.com Received: 22.05.2016 Accepted: 28.06.2016 Abstract- The aim of this paper is to design and construct a solar photovoltaic system that can receive a maximum power from sun. Two solar panels, two stepping motors and one Atmega IC were used in this design. One of the panels rotates 200 steps in a complete round and 200 voltage samples are received from the stepping motor to be carried to the main panel, which commands the best movement toward the best position. Maximum power point tracking (MPPT) has been conducted using an online method. As such, the proposed system has also been tried via MATLAB software. The simulation results confirm the proposed approach. Keywords: Solar Panel, Stepping Motor, Maximum Power Point Tracking (MPPT). 1. Introduction Solar energy, as a green energy resource, can be used to supply many energy usages in the form of thermal and/or electric energy. Given the increased cost of energy obtained from fossil fuels, as science and technology progress, the cost of energy production using renewable energies decreases and approaches economic efficiency [1-3]. Solar energy enjoys a host of advantages including worldwide availability and numerous applications in various fields[10,11]. The Sun is the biggest and the only energy source for earth, the energy emitted from which is used in different ways in order to supply the usages that otherwise were supplied by fossil and non-fossil fuels. Various methods have been proposed in maxim power point tracking in order to achieve the maximum energy from solar panels, including: 1) offline methods such as: Open Circuit Voltage (OCV) [3], Short-Circuit Current (SCC) [4], and 2) online methods such as perturbcance and observation (P&O)[9-10], Extremum-Seeking Control (ESC) method and IncCond method; and 3) Hybrid methods. One of the disadvantages of offline methods is their power loss, because in both OCV and SCC methods there is a need to stop the load on solar panel. This can lead to power loss. In online methods[11,12], P&O method suffers from two main disadvantages: first, in this algorithm, the employed perturbation range in the system is the main factor of variation in both oscillations and the output power convergence rate, in which a higher perturbation leads to a higher oscillation range and if the perturbation is low, the oscillation range around MPP reduces to minimum but the convergence rate will continue to reduce. Second, if the working variations in the system is fast, the algorithm can lead to an error in tracking. ESC method does not have the disadvantages of P&O method, but its implementation is very complex and its evaluation signal has a small range [1]. IncCond method is an effective method under high speed and environmental variations. However, its main disadvantage is that this method requires complex control circuits. In hybrid methods the control signal is connected to two parts and each part is placed on an independent algorithm loop: the first part is associated with the offline part, determined by environmental conditions of the problem such as light intensity and temperature, and the second part is conducted using online tracking method. In this paper both the environmental conditions of the problem and the control section have been designed through an online method. The basics of the system, the control part, stepping motor, ATmega IC and the simulation results are presented in the next sections. The last section concludes the paper. 2. Basics of the System The photovoltaic system used in this paper is consisted of: 1- solar panel; 2- stepping motor; and 3- controlling board. The proposed approach in this paper is presented in figure 1.