Adaptive DC-Link Voltage Control for Shunt Active Power Filters Based on Model Predictive Control

Abstract

DC-link voltage directly affects the compensation range and performance of shunt active power filters (SAPFs). DC-link voltage in SAPF is generally high, fixed, and dependent on rated power. DC-link voltage could become excessive in low-load conditions, which increases switching loss and switching noise. Optimized DC-link voltage was obtained in this study to enhance compensation adaptability for variable nonlinear loads and fluctuation in grid voltage. We proposed a novel adaptive DC-link voltage control for SAPFs, which reduced switching noise and switching loss during operation. The proposed DC-link voltage control method employed model predictive current control, proportional voltage control and calculation of optimal DC-link voltage. A real-time observer, which was insensitive to distorted grid condition, was used to capture peak grid voltage. Finally, simulations and the results of experiments were used to verify the effectiveness and feasibility of the proposed DC-link voltage control method.