Developing Control Method Based on the Theory of Fuzzy Sets for MPPT in Solar Arrays

Abstract

In this paper, a new hybrid method is presented by combining the fuzzy logic controller and using boost converter. Presented fuzzy logic controller does precise and fast tracking of maximum power point in different environmental conditions (light and temperature). The modelling of this method will result in obtaining a more accurate response from the system. The characteristics of photovoltaic systems are inherently nonlinear and depending on functions of environmental parameters such as light, ambient temperature, and its attaching charge. Thus, we can receive the maximum power from PV array by choosing appropriate operating point when the amount of light and temperature are constant. By modifications in environmental conditions (light and temperature), the operating point of array will be changed and consequently by using different methods of maximum power point tracking (MPPT). MPPT can be always kept as receiving power amount from array at its maximum value, in other words, it can track maximum power point. There are several ways to track the maximum power. In order to optimizing use of these modules and the growing reduction of tracking costs of solar systems, the use of power processor in order to achieve maximum power point and control method based on Mamdani's fuzzy inference method is presented in this paper. In proposal method, duty cycle switching of power processor attached to a solar module has been controlled in a way to obtain maximum power point of module under various conditions of temperature and light intensity. An important advantage obtained by comparing with previous methods is that the control method independency of module type is used and there is no need for reference signal or any kind of physical information about nature of module. The advantage of fuzzy controllers is in working with imprecise and nonlinear inputs; there is no need of accurate mathematical model and fast convergence and the lowest fluctuations in MPPT.