Stability and dynamic analysis of the electric vehicle flywheel rotor with active magnetic levitation bearings including time delay

The time delays present in the active magnetic bearings (AMB) systems are small and have generally been ignored. However, even if the unpredicted or unconsidered time delays are small, they may have a significant influence on the stability behavior of the feedback-controlled rotor systems. In this work, an electric vehicle flywheel energy storage system (EV-FESS) is modeled as a single disc high-speed rotor system supporting the AMB. The time delay arising through the feedback control loop has been included in the model, and its effect on the overall control and stability of the system has been considered. The system has been modeled as a simplified rotor finite element model based on the Timoshenko beam theory. Initially, the present method is validated with the benchmark literature and experimental results. Further, the dynamics of the system were studied under the lower, medium, and high speed operations. A comparison study is shown with and without a time delay on the dynamic response of the systems under different operating speeds. The parametric studies were also carried out to identify the influence of the proportional and derivative gains on the system’s responses. The influence of the time delay, along with the other driving parameters such as base excitation, short shock, and sensor drift, on the dynamic response of the system is studied. The system is in a stable state with longer delays at lower speeds, whereas the system goes unstable at medium and higher speeds with longer delays.