Title
Single-Sensor Control of LCL-Filtered Grid-Connected Inverters.
Abstract
Owing to the filter resonance and background harmonics, the current control for the LCL-filtered grid-connected inverter should be carefully designed to ensure stable operation. Prior-art current control methods normally require extra sensors to achieve the damping of the resonance, or sophisticated active damping should be employed. Both increase the overall system cost and complexity. In this context, an improved control strategy is proposed for LCL-filtered inverters. The proposed control method utilizes a novel reduced-order observer in a way that only one current sensor is required for stable operation (i.e., resonance and harmonics are effectively attenuated). More specifically, the reduced-order observer embeds the dynamics of the grid voltage, where the estimated grid information is used for synchronization in a phase-locked loop. The estimated state variables of the observer are then used for the controller design. Furthermore, to achieve active damping and suppress the influence of grid voltage distortions on the current quality, a multi-resonant state-space controller is proposed, where a linear quadratic regulator method is employed to obtain the optimal gain. The simulations and experimental tests are performed on a 3-kW grid-connected inverter system with an LCL filter. The results demonstrate the effectiveness of the proposed method in terms of robust active damping and strong harmonic attenuation, and thus the inverter achieves a good power quality with only one current sensor.
Year
DOI
Venue
2019
10.1109/ACCESS.2019.2906239
IEEE ACCESS
Keywords
Field
DocType
Active damping,linear quadratic regulator,multi-resonant controller,reduced-order observer,state-space control
Inverter,Control theory,Control theory,Computer science,Harmonic,Harmonics,Current sensor,Observer (quantum physics),Linear-quadratic regulator,Grid,Distributed computing
Journal
Volume
ISSN
Citations 
7
2169-3536
0
PageRank 
References 
Authors
0.34
0
8
Name
Order
Citations
PageRank
Mei Su17924.27
Bin Cheng29712.57
Yao Sun34118.81
Zhongting Tang400.34
Bin Guo51603143.97
Yongheng Yang63015.47
Frede Blaabjerg71195248.32
Hui Wang8105.03