OSV-MPC for Harmonic and Zero-Sequence Compensation in Four-Wire Off-Grid Microgeneration Systems Based on SEIG

Abstract

This paper proposes a finite control set model predictive control (FCS-MPC) strategy to address voltage regulation in isolated four-wire microgeneration systems based on self-excited induction generators. The FCS-MPC approach enables a simpler and more functional imbalance controller design. The controller determines the optimal switching vector through a cost function that employs a weighting factor for the different control variables. It effectively tracks distorted current references and prevents voltage imbalance, even in a system without frequency regulation. The employed inverter is a four-leg voltage source inverter, also known as a distribution static synchronous compensator, which provides the necessary reactive power and compensates for harmonic content along with the zero-sequence component, ensuring balanced three-phase voltages at the point of common coupling, even with unbalanced loads. The proposed control leverages the instantaneous power theory for synchronization, thereby replacing methods such as the phase-locked loop. Experimental results validate the effectiveness of the proposed control approach and assess the performance of the system in accordance with power quality standards.

Keywords

• Off-Grid Microgeneration
• Induction Generator
• Four-Wire System
• Model Predictive Control
• Zero-Sequence Voltage
• Harmonic Current Compensation