Robust Fractional Order Speed Controllers for Induction Motor Under Parameter Variations and Low Speed Operating Regions

This brief describes the two unique Fractional Order (FO) speed controllers’ FOPI and FO[PI] design and validation for the induction motor drive. The detuning of the conventional PI controller issues under machine parameter variations and low speed operating regions are overcome by the proposed two types of FO speed controllers. This brief presents the novel FO controller design procedure for the Voltage Source Inverter (VSI) fed IM. The actual FO VSI fed IM transfer function model is identified using the chirp signal injection method with the Hardware-In-Loop (HIL) system for the laboratory prototype. The parameter variation is subjected to different stator winding resistance machines of the same rating. The rotor inertia change of up to eight times the no-load value is incorporated to investigate the robust performance of these speed controllers under dynamic operating conditions. The performance of the designed$FOPI$and$FO[PI]$controllers are analyzed at low speeds. The results show the supremacy of the$FO[PI]$controller over the$FOPI$and PI under the same stability boundary limits. The experimental validation of these controllers is provided.