High-Performance Control of Three-Phase Four-Wire DVR Systems using Feedback Linearization

Abstract

Power quality is a critical issue in distribution systems, where a dynamic voltage restorer (DVR) is commonly used to mitigate the voltage disturbances for loads. This paper deals with a nonlinear control for the three-phase four-wire (3P-4W) DVR under a grid voltage unbalance and nonlinear loads in the distribution system, where a novel control scheme based on the feedback linearization technique is proposed. Through feedback linearization, a nonlinear model of a DVR with a PWM voltage-source inverter (VSI) and LC filters is linearized. Then, the controller design of the linearized model is performed by applying the linear control theory, where the load voltages are kept constant by controlling the d-q-0 axis components of the DVR output voltages. To keep the load voltage unchanged, an in-phase compensation strategy is employed, where the load voltages are recovered to be the same as the previous voltage without a change in the magnitude. With this strategy, the performance of the DVR becomes faster and more stable even under unbalanced source voltages and nonlinear loads. The validity of the proposed control strategy has been verified by simulation and experimental results.

Feedback Linearization-Based Control Strategy for Interlinking Inverters of Hybrid AC/DC Microgrids with Seamless Operation Mode Transition

“…Therefore, the droop control to determine the power-sharing among the interlinking inverters in the microgrid is not considered in this paper. From Figure 1, the modeling of the ILI is expressed through dq-axis components of the voltages and currents as [27][28][29] i rd = i cd − C f . e ld + ω e C f e lq (1)…”

A Generalized Parameter Tuning Method of Proportional-Resonant Controllers for Dynamic Voltage Restorers

“…Therefore, the control scheme is complicated and insufficiently reliable. To eliminate voltage sags and swells, several alternative topologies of DVR have been introduced such as a three-phase inverters with a neutral point created by a DC-link capacitor, three-phase four-wire inverters, and three single-phase fullbridge inverters with a common DC-link capacitor [6], [7]. The latter is preferred because of the simple pulsewidth modulation (PWM) method.…”