An optimal current control scheme in grid-tied hybrid energy system with active power filter for harmonic mitigation

This paper presents hybrid photovoltaic (PV)-wind-battery energy storage network tied to three-phase utility grid side inverter using fuzzy logic proportional integral derivative-improved second-order generalized integrator-quadrature signal generator-phase locked loop (FLPID-ISOGI-PLL) for power quality enhancement at the consumer side terminals. An advanced ISOGI-PLL control strategy is implemented to separate the fundamental constituent of each phase load current without sensing other phase currents, which makes phase independent and reliable. It has several characteristics, such as improved hybrid system (HS) power penetration, load sharing, and power factor correction. Additionally, FLPID adaptive voltage controller is incorporated in the presented scheme to enhance dynamic operation of the system and also keeping the power balance between the dc and ac sides by maintaining the dc bus voltage. Moreover, the photovoltaic system's feed-forward constituent is incorporated in the proposed technique, which improves the system dynamic performance and minimizes oscillations in grid currents. The outcomes of the advanced control strategy are found adequate for enhancing active power filter (APF) performance at the consumer side terminals under several operating conditions. The proposed control technique is computationally analyzed by simulating the system through MATLAB/SIMULINK under steady state, dynamic, load removed, and unbalanced grid voltage conditions. The competency of an advanced control approach is examined with hardware-in-loop (HIL) co-simulation using FPGA Virtex-7 VC-707 via very high speed integrated circuit hardware description language (VHDL) code generation. Finally, the simulation outcomes are verified through a real-time prototype laboratory platform using FPGA Virtex-7 VC-707 evaluation kit, and the total harmonic distortion (THD) analysis of injected grid currents is tabulated under different operating scenarios and found good within the IEEE-519 standard limits.