High-Performance Grid Current Feedback Control for Three-Phase Voltage-Source Converter with an LCL Filter Under Distorted Grid Conditions

Abstract

This paper presents the implementation of the proportional resonant plus multi-resonant (PR-MR) and practical proportional resonant plus multi-resonant (PMR-MR) harmonic controllers in the current control loop to mitigate the high-order harmonic currents. The harmonic controllers, of orders 5th, 7th, 11th, and 13th with proper discretization methods are added to the fundamental controller in the stationary reference frame to mitigate the grid current harmonics caused by the distorted grid voltages. An extensive current control design procedure, proper methods of discretization of the resonant controllers, and system stability analysis are presented. The experimental grid currents show a lower total harmonic distortion close to 1.1% under the distorted grid conditions and comply with the IEEE 1547 standard. The PR-MR and PMR-MR controllers were implemented on the TMDSDOCK28379D 32-bit floating-point digital signal processor. The system is simulated in MAT-LAB/Simulink environment and experimentally implemented on a 7.5 kW three-phase LCL-filtered grid-connected VSC with the proposed control schemes.