Research On Interior-Circumferential Permanent Magnet Synchronous Machineand Its Hybrid Excitation Technology

Permanent magnet synchronous machines(PMSMs) have the advantages of high efficiency, high power density and high reliability. Air-gap magnetic field of electro-magnetic machines is adjustable. Hybrid excitation technology makes reasonable combination of permanent magnet excitation and electro-magnetic excitation, which has a bright future for the electric vehicle drive system and aircraft power system.Interior-circumferential permanent magnet synchronous machine is firstly investigated. The coordination of numbers of poles and stator slots, the dimension of the permanent magnets are analyzed.The contribution of reluctance torque to the electromagnetic torque, the influence of difference between electromagnetic model and actual processing structure are analyzed with finite element analysis. To increase the output toque, the influence of stator slot dimension and magnetic isolation slot on the output capability under motoring operation is discussed based on the analysis of armature reaction.Hybrid excitation synchronous machine(HESM) with magnetic shunt rotor is developed from interior-circumferential PMSM with the hybrid excitation technology, capturing the merits of high power density and field regulation capability. Influences of the introduction of magnetic shunt structure on armature reaction, inductance feature, output power under generating and motoring operation and the operating point of the permanent magnets are analyzed for the comparative analysis between the HESM with magnetic shunt rotor and interior-circumferential PMSM. Two novel topologies of HESM with interior magnetic bridge and HESM with non-uniform air-gaps are proposed and analyzed based on the principle of magnetic shunt. The influence of excitation current regulation on constant power operation characteristics and loss is further discussed.100k W interior-circumferential PMSM prototype and 100 k W HESM with magnetic shunt rotor are developed, and test rig is established. The influence of magnetic shunt structure on output performance under generating and motoring operation is verified. The effect of flux weakening control with excitation current and d-axis current on motoring operation is analyzed. It is verified that the HESM with magnetic shunt rotor could operate with high efficiency under a wide operation region with the coordinated control of excitation current and d-axis current, and efficiency in most regions exceedes over 92%.