Design of a modified electronic load controller using hybrid optimization for reliable SEIG-based microhydro electrification

Abstract

This study introduces a modified electronic load controller (ELC) that is integrated with a self-excited induction generator (SEIG) to ensure consistent and stable power generation in microhydro-based rural electrification systems. To improve the SEIG-ELC system’s dynamic performance, the parameters of the proportional-integral (PI) controller are optimally adjusted using a hybrid particle swarm optimization-gradient descent (PSO-GD) method. This method merges the global search ability of PSO with the local refinement strength of GD. The effectiveness of the proposed method is experimentally confirmed through two comparative tests conducted on a laboratory-scale 2.2 kW, 415 V, 4.8 A, 50 Hz, delta-connected three-phase SEIG, which powers a three-phase resistive main load and a controllable dump load. In the initial test, the PI controller utilizes PSO-GD optimized gains of ( Kp = 0.45) and ( Ki = 12), while the second test applies traditionally tuned gains of ( Kp = 1.20) and ( Ki = 35). Using a Fluke 435-II power quality analyzer, experimental data on source voltage, source current, dump-load voltage, and dump-load current are collected under various loading scenarios, with sudden load shifts. The PSO-GD optimized controller proposed in this study achieves a settling time of 25 ms, which is 40% faster than the traditional controller. Compared to their nominal values, this controller improves the mean voltage accuracy by 29.12% and the mean frequency accuracy by 75.23%. Additionally, the voltage variance and standard deviation are decreased by 75% and 50%, respectively, while the frequency variance and standard deviation are reduced by 93.73% and 74.95%, respectively, indicating significantly improved voltage and frequency stability during sudden load changes. The regulated output voltage maintains a total harmonic distortion (THD) of 5.8%, with the 5th, 7th, 11th, and 13th harmonic components restricted to 3.82%, 2.64%, 1.85%, and 1.42%, respectively, complying with the IEEE 519–2022 standards for low-voltage systems below 1 kV. The experimental findings reveal that the hybrid PSO-GD optimized ELC markedly improves transient response, voltage and frequency regulation, stability, and power quality when compared to traditional PI tuning. This offers a reliable control solution for SEIG-based micro-hydro power systems.