An Improved Fractional Voltage Based MPPT Technique for PV Generation System

Abstract

The utilization of photovoltaic energy is escalating day by day, this leads to development of new techniques which can utilize the photovoltaic power with maximum efficiency. The photovoltaic system must operate at maximum power point(MPP) in order to enhance the overall system efficiency. The MPP is that point on the P-V curve where photovoltaic power for a given condition of radiation and temperature becomes maximum. However, the non linear characteristics of PV module make it difficult to track the MPP. This paper presents an improved Fractional voltage based maximum power point tracking (MPPT) scheme to extract maximum pow)er from photovoltaic system under constant and varying irradiance condition. The traditional MPPT methods like perturb & observe, fractional voltage & current methods are much simpler to implement but they suffer from poor efficiency, inability to track MPP under varying conditions of irradiance, oscillations/fluctuations around MPP etc. The proposed technique overcomes the drawbacks by PI controller with Grey Wolf Optimization technique. The suggested method tracks MPP efficiently even in the presence of varying irradiance and the oscillations in power are quite less as compared to conventional techniques. The effectiveness of the suggested technique is evaluated by comparing the tracking performance with the conventional perturb & observe and incremental conductance under the irradiance of varying amplitude.