1424 words - 6 pages

Abstract-Many different techniques for maximum power point tracking of photovoltaic arrays were introduced. This paper develops an adaptive maximum power point tracking (MPPT) algorithm for optimizing solar array performance based on incremental conductance (INC) and gradient descent algorithm .In conventional INC method the step size determines how fast the MPP is tracked. Fast tracking can be achieved with bigger increments but the system might not operate exactly at the MPP and oscillate about it instead; so there is a tradeoff between the time needed to reach the MPP and the oscillation error. In this work we have an adaptive step that brings the operating point of the PV array close to the MPP with a bigger step size and then uses INC to exactly track the MPP with a lower step. The experimental results show the notable improvement in the time needed to reach the MPP and also minor oscillation error which increases the accuracy of the system. The method was simulated in PSIM.

Index Terms—Maximum Power Point Tracking (MPPT), Incremental conductance (INC), Adaptive incremental conductance (AINC)

INTRODUCTION

Solar energy is one of the most important renewable energy sources that has been gaining increased attention in recent years. Solar energy is plentiful; it has the greatest availability compared to other energy sources. The amount of energy supplied to the earth in one day by the sun is sufficient to power the total energy needs of the earth for one year [1]. Nowadays research on solar power generates great interest in achieving the only aim to get the maximum energy that PV can provide. The power generated from a given PV module mainly depends on solar irradiance and temperature. For optimal operation of a PV module, its terminal voltage must be equal to the corresponding MPP value. To achieve these goals, various conventional MPP tracking (MPPT) algorithms[2,3] such as Incremental Conductance, Perturbation and Observation (P&O), Hill Climbing, Parasitic Capacitance and Constant Voltage and Current algorithm. Although its complexity, most usual MPPT algorithm is Incremental Conductance due to several advantages that presents in comparison with others have been proposed and used to extract maximum power from PV arrays under different operating conditions. Current research in the field of Maximum Power Point Trackers focuses on new and more flexible ways for duty ratio step size changing. In this paper, a new approach of incremental conductance (INC) algorithm which makes use of a variable step of desirable voltage change is presented by an adaptive method. This algorithm is applied on a DC/DC boost converter. The whole system is simulated using PSIM and some useful results are presented.

PV Models and Equivalent Circuits

A PV model can be expressed by the equivalent circuit shown in Figure 1 This model is also known as a single-diode model In this model, open-circuit voltage and short-circuit current are the key parameters....

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