A Method to Maximize Torque Density in MGs for Synchronous Condensers and Flywheel ESS

For magnetic gears (MGs) employed in flywheel and synchronous condenser energy storage systems (ESS), this paper introduces a method to maximize torque density under stress constraints. Initially, the minimum safe internal air-gap length under stress constraints is determined using the theory of thick cylinders. Subsequently, employing the Precise Sub domain Analytical Method (PSAM) and the stress tensor method, a mathematical analytical model of the magnetic gear's output torque is developed. This yields extensive data on the maximum static torque values. Thereafter, a surrogate model is created based on the Neural Network Radial Basis Function (NNRBF) model, and the optimal solution for torque density is attained using a Multi-Island Genetic Algorithm (MIGA). Finally, the validity of the proposed method is confirmed through Finite Element Analysis (FEA).