Derated Mode of Power Generation in PV System Using Modified Perturb and Observe MPPT Algorithm

Abstract

In a grid-integrated photovoltaic system (GIPVS), issues such as surplus active power and inadequate performance of maximum power point tracking (MPPT) exist. A surplus active power causes the overvoltage problem at the point of common coupling in low or medium voltage level grid during the peak hours of power generation. Additionally, the inadequate performance of the MPPT technique results in the power loss due to high settling time during the sudden change in irradiance. Therefore, to solve the surplus power problem, the curtailment of active power is suggested with improved MPPT algorithm in variable irradiance conditions. In this paper, a derated power generation mode (DPGM) control strategy is presented for the curtailment of active power. Additionally, a drift free (named as modified) Perturb & Observe (P&O) is also proposed to improve the performance of the MPPT algorithm. Consequently, the DPGM control scheme with the intermediate boost converter shaves the surplus active power during the peak hours of power generation. Furthermore, the modified MPPT algorithm deals with the fluctuation of irradiance during non-peak hours. Thus, the proposed control scheme delivers in a more efficient system during the peak hours of power generation. In addition, it reduces the power loss and settling time during the change in irradiance for non-peak hours. In the support of the proposed control scheme, a 30 kW system has been simulated in the MATLAB/Simulink using Simpower tools under different environmental conditions.