WOA–PSO of fractional-order PID control for arc plasma power supply inverter modules

The inverter module, as a critical device in arc plasma power supplies for converting DC to AC, often encounters issues such as stability errors and system disturbances due to the impact of shock loads when tracking rated voltage and frequency signals. This paper proposes an improved Particle Swarm Optimization (PSO) strategy for Fractional-Order PID (FOPID) control with limited parameter selection, aiming to address the poor performance of inverter modules in arc plasma power supply systems. The proposed strategy incorporates the spiral position updating mode from the Whale Optimization Algorithm into the position updating process of PSO, which improves particle diversity, global search capability and optimization stability. The effectiveness of the proposed method is verified by comparing it with the Ziegler–Nichols tuning method and the standard PSO algorithm in the MATLAB/Simulink simulation environment. A model of an inverter system is established for validation purposes. The results indicate that applying the improved PSO-based FOPID control strategy to the inverter process of the arc plasma power supply system significantly enhances the output waveform quality, reduces harmonic distortion, and achieves excellent control performance.