Design of MPPT controller for on-grid PV systems

Abstract

ABSTRACT

Maximum energy utilization using tracking, search, and optimization algorithms are considered an integral design requirement of PV system. The photovoltaic (PV) array output power is variable based on insolation/irradiation and junction temperature. The maximum power point tracking (MPPT) controller is added to the PV array, in order to increase an energy efficient operation of installed PV array. Conventional control methods of MPPT are perturbation and observation (P&O) method and incremental conductance(IC) method, etc. Regardless the simplicity of the used search algorithms, all suffer from two drawbacks. Firstly, as the search approaches the MPP operating zone, the controller forced the operating point to chatter and keep oscillating around the MPP. Secondly, any changes in irradiation level cause loss of tracking and a severe change in MPP search direction. The solar cell is affected by its surroundings, such as shadowing from nearby buildings and scattered clouds. The result is that operating P–V curve for the PV array has multiple operating PowerPoint-peaks, different from the assumed single peak curve in normal irradiation. Conventional MPPT methods (such as P&O &IC) are possibly ineffective to severe shadowing and partial clouding conditions.