Dynamic behavior and stability of energy efficient electro-magnetic suspension of rotors involving time delay

Energy efficient contact less suspension of high-speed rotor shafts in application areas such as power-plants and Flywheel Storage Systems (FESS), can be achieved through Active Magnetic Bearings (AMBs). Inevitably, there exists time delay sensing the displacement actual control force by electromagnets, thus leading to system instability. This paper therefore analyses stability AMBs, with constant delay. FESS is modelled a rigid rotor-AMB system. Performance two different laws, (i) PID (ii) recently introduced Four-Element (FE) law, are compared. The governing equations transformed frequency domain, exploit Pade's approximation modeling delayed value feedback signal analysis carried out analyzing poles. methodology has been verified using experimental results from existing literature. Numerical simulation differential also used validate analytical results. FE law shows promise tolerating delay, compared conventional controller AMB higher possible spin speed relaxed sampling constraints on instrumentation. One prospective applications this work design flywheel energy storage systems for an electric vehicle.