On the Improvements of Perturb-and-Observe-Based MPPT in PV Systems

Abstract

There exist numerous maximum power point tracking techniques in today’s market to maintain the operation of PV module at maximum power irrespective of the solar irradiation level and ambient temperature such as perturb-and-observe (P&O) method, incremental conductance (InCond) method, fractional short-circuit current (FSCC) method, and fractional open-circuit voltage (FOCV) method. The perturb-and-observe (P&O) method is the most popular one because of its easy implementation. The classical perturb-and-observe method may fail or deviate from tracking the right direction to capture the correct maximum power point (MPP) of a PV module exposed to a suddenly changed solar irradiation or ambient temperature. The classical method fails to capture the MPP when the solar irradiation or ambient temperature follows a ramp with different slopes. This is because the method can’t discriminate whether the change in module power is due to its own voltage perturbation or due to the change in the irradiation or ambient temperature level. Numerous approaches for improving, adapting, and optimizing the classical P&O method have been published. However, they differ in many aspects such as tracking speed, tracking accuracy, steady-state efficiency, and dynamic efficiency as well as the number of used sensors, complexity, and cost. This chapter is aimed at reporting on the improvements made on the classical perturb-and-observe method under sudden or ramp variations of irradiation level and/or ambient temperature with their advantages and disadvantages as documented in the literature. This chapter is framed as a review chapter.