A New Multi-Axial Flux Pm Motor–Generator System for Flywheel Energy Storage

This study presents a flywheel energy storage system utilizing a new multi-axial flux permanent magnet (MAFPM) motor–generator for coil launchers. The traditional winding structure of the flywheel is effective for energy recovery over several minutes. However, because the projectile is launched from coil launchers in less than one second, the traditional winding structure experiences insulation deterioration and winding damage due to the high current. This study proposes a winding structure made of an 8 × 0.5 mm conductor with eight turns to meet the energy requirements of coil launchers. Furthermore, the motor winding was divided into two sections, which were compared using both series and parallel connection methods as described in the literature. The proposed system produces energy that is 29.96%, 85.63%, and 81.11% lower than the A winding (where A and B are identical), the A + B winding (series connected), and A//B winding (parallel connected) at the same speed. However, as the speed increases by 258.26%, the energy output rises by 215.88%. The flywheel motor–generator’s series-parallel winding structure reaches its current carrying capacity at 1188 rpm. By utilizing a separate winding instead of the traditional motor–generator winding, a current of 38.4 A is achieved, ensuring that the winding’s current carrying capacity remains within the design parameters. Experimental data have proven that the proposed multi-wire winding structure is an innovative solution for coil launchers, surpassing various combinations of motor–generator windings found in the literature. Furthermore, the placement of the proposed winding in a single slot in the design ensures a compact structure.