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Mathematical Problems in Engineering
Volume 2014, Article ID 129619, 9 pages
Research Article

Research on Discretization PI Control Technology of Single-Phase Grid-Connected Inverter with LCL Filter

1College of Defense Engineering, PLA University of Science and Technology, Nanjing 210007, China
2Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

Received 1 June 2014; Revised 10 August 2014; Accepted 15 August 2014; Published 29 September 2014

Academic Editor: Victor Sreeram

Copyright © 2014 Jianke Li et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Compared with L-type filter, LCL-type filter is more suitable for high-power low-switching frequency applications with reducing the inductance, improving dynamic performance. However, the parameter design for the LCL filter is more complex due to the influence of the controller response performance of the converter. If the harmonic current around switching frequency can be fully suppressed, it is possible for inverter to decrease the total inductance as well as the size and the cost. In this paper, the model of the LCL filter is analyzed and numerical algorithms are adopted to analyze the stability of the closed-loop control system and stable regions are deduced with different parameters of LCL filter. Then, the minimum sampling frequencies are deduced with different conditions. Simulation and experimental results are provided to validate the research on the generating mechanism for the unstable region of sampling frequency.