Metamodel of a Hybrid-Excited Flux-Switching Machine for Operating Cycle Optimization of Long- Term Flywheel Energy Storage Systems

This paper proposes a methodology to quantify the performance of a 12/10 outer rotor Hybrid-Excited Flux-Switching Machine (HE- FSM) over its operating cycle with a view to optimizing its design parameters for a long-term Flywheel Energy Storage System (FESS) application. A low-computational-cost metamodel of the machine is built from the data provided by the Finite Element Model (FEM), to estimate the iron losses and the output torque at the operating points consituting an operating cycle, with a rms error of 1.92% and 1.21 %, respectively. A preliminary design of a HE-FSM is simulated in a fictional 2kWh FESS and exhibits a maximal energy efficiency of 78.73% for a duration of storage of 2 hours. The minimization of the total losses thanks to negative
$d$
axis and field winding current densities allows for a reduction of up to 43 % of the no load losses.