Study on different Maximum Power Point Tracking (MPPT) algorithms for grid connected PV inverters

Abstract

Recent changes within the electricity industry, such as the 2% new renewable energy targets and green energy marketing schemes will see significant growth in the number of photovoltaic (PV) generating systems connected to the grid. PV system that uses the photovoltaic array as a source of electrical power supply has an optimum operating point, called the maximum power point (MPP) which varies mainly depending on cell temperature and irradiation level. Thus, a maximum power point tracking (MPPT) scheme is needed to operate the PV array at its maximum power point. The MPPT works by automatically tracking the MPP of the PV array so that the overall PV system would have highest performance in terms of the power generated from the PV array will be optimally consumed. The project concentrates on the extensive study with regards to different MPPT algorithms that have been implemented in PV inverter for grid-connected PV system. There are two most widely used algorithms that will be developed namely; Perturbation and Observation (P&O), and Incremental Conductance (INC). The simulation studies are carried out in MATLAB/Simulink. The performance analysis with regards to the MPPT convergence speed and efficiency for both MPPT algorithms are evaluated. Simulation results show that the MPPT with INC algorithm offers the best performance in terms of its fastest response in tracking new MPP and highest efficiency under rapid change of irradiance level as compared to the MPPT with P&O algorithm.