Comparison of Toroidal and Tooth-Coil Winding 2-Pole Slotted High-Speed Permanent Magnet Motors

This article compares the electromagnetic performance of 6-slot/2-pole slotted high-speed permanent magnet (HSPM) motors with toroidal and tooth-coil windings. Both HSPM motors are optimized for maximum torque by analytical and finite element (FE) methods considering maximum winding temperature allowance. It is found that under the stator loss and thermal limitations, the optimized toroidally wound motor has less effective stator iron volume and lower stator iron loss compared to its tooth-coil counterpart while producing higher electromagnetic torque and exhibiting higher efficiency. Furthermore, the scalability analyses indicate that the enhanced torque production resulting from toroidal winding remains consistent as the rated speed increases, and further increases with the increasing stator active length. However, it diminishes with the reduced lamination thickness and corresponding iron loss. Finally, the analytical and FE predicted results are verified experimentally by the prototype tooth and toroidally wound HSPM motors.