Implementation of frequency integrated multi-order generalized integrator for solar energy sourced grid

Abstract

This work presents a frequency integrated approach on a multi-order generalized integrator and a self-tuned discrete proportional plus integral regulator (PIR) for three-phase double-stage grid tied photovoltaic (PV) energy system, where the peak power is extracted from PV system and feed to the load and the grid. The function of this novel frequency integrated multi-order generalized integrator (FIMOGI) is to attenuate the higher-order and sub-order harmonic components from distorted load currents, even when the load currents are linear or nonlinear and balanced or unbalanced. Integrated frequency approach removes the switching frequency variation of VSC without addition of a FLL and improves the synchronization of VSC power fed to the grid. Moreover, self-tuned PIR is used to regulate the DC-link voltage under different dynamic and disturbance conditions. To improve the transient performance, a PV power feed-forward term is included in the implemented control. The proposed FIMOGI controller is modelled and the control is developed in Simulink environment as well as its performance is validated on a developed laboratory prototype. The simulated and experimental performance is carried out under nonlinear balanced and unbalanced load, and solar insolation increase and decrease. The grid current condition measured in terms of total harmonics distortion, during Simulation and validation are found under the restrained of IEEE-519 standard in different working condition, which exhibits the efficacy of the implemented control.