Hybrid Metaheuristic Approach for Optimal LCL-Filter Design in Grid-Connected Inverters Using CSA-PSO with Adaptive Parameter Tuning

This paper presents a hybrid Circle Search Algorithm with Particle Swarm Optimization (CSA-PSO) for optimizing LCL filter design in grid-connected inverters. The proposed method achieves significant performance enhancements, including a 32.7% reduction in Total Harmonic Distortion (THD) from 2.45% to 1.65%, and substantial reductions in component sizes: L1 (3.6mH to 2.82mH, -22%), L2 (1.2mH to 0.81mH, -32%), and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$C$</tex> (4.7MF to 2.50MF, -47%). Dynamic performance analysis demonstrates 48 % lower overshoot (6.4 % vs. 12.3 %) and 33 % faster settling time (12 ms vs. 18 ms), During 90 % grid voltage sags, CSA - PSO achieves 38 % lower current oscillation compared to traditional methods. Harmonic spectrum analysis reveals superior attenuation, with a 25 % improvement in the fundamental frequency component and a 45% reduction in high-frequency harmonics. The steady-state response shows improved current tracking, reducing ripple from 0.85 A to 0.42 A, while three-dimensional spectral analysis confirms enhanced harmonic suppression across all frequencies, particularly a 40 % average reduction in the critical 2nd-13th harmonic range. The optimized design complies with IEEE 519–2014 and IEC 61000-3-2 standards while reducing component costs by 35 %. Simulated fault ride- through tests show a 42 % faster recovery time after fault clearance” maintaining stability margins above 45° and 6 dB.