A Fuzzy Logic Control Strategy for Frequency and Voltage Regulation of the LLCL-Filter-Based Synchronverter System
Received: 22 July 2025 | Revised: 14 August 2025 and 5 September 2025 | Accepted: 6 September 2025 | Online: 8 December 2025
Corresponding author: Thai An Nguyen
Abstract
This paper proposes a control strategy employing Fuzzy Logic Control (FLC) to mitigate the voltage variation of the LLCL filter synchronverter system under various operating conditions, especially during an islanding scenario. The proposed strategy utilized an FLC-based adaptive control method for optimizing the integral coefficient of the reactive power control phase, the damping and virtual inertia coefficients, and defining a new approach in operating the reactive power control phase of the conventional LLCL filter synchronverter system. The proposed control strategy effectively suppresses the voltage variation phenomena during the off-grid operation, grid-connected modes, and islanding transitions while improving the frequency response under off-grid conditions and enhancing the output current performance under grid-tie scenarios. The simulations of the proposed control strategy of the LLCL filter synchronverter system are conducted in MATLAB/Simulink platform through various operating scenarios. The simulation results validated the improvements in voltage, frequency, and output current response compared to the conventional approach. Thus, enhancing the grid stability and power quality at the point of common coupling facilitates a more reliable integration of synchronverter-based distributed generation systems into modern power networks.
Keywords:
synchronverter, adaptive control, virtual inertia, LLCL, FLC, VSGDownloads
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