Numerical Analysis of a Fractional Slot Concentrated Winding Synchronous Machine with Series Hybrid Excitation

Numerical analysis results of a series hybrid excitation synchronous machine (HESM) are presented into this paper. The analyzed structure refers to a three-phase fractional slot concentrated winding (FSCW) synchronous machine with 9 stator slots and 8 surface mounted permanent magnets rotor poles with an additional excitation winding. The use of hybrid excitation offers the synchronous machine the combined advantages of the permanent magnet and the electromagnetic excitation, ensuring high efficiency and flexibility. The possibility of adjusting the rotor magnetic flux in such machines allows to achieve high no-load flux linkage for high torque at low speeds, as well as high torque in a wide speed range. The unique features of the working characteristics are analyzed and explained.