Electromagnetic Design and Advanced Thermal Management of Novel Modular Consequent Pole Permanent Magnet Machines

This thesis is mainly focused on the investigation of consequent pole permanent magnet machines (CPMs). The main research topics are: 1) investigation of the influence of winding configurations and rotor structures on machine performance, 2) electromagnetic design of the modular CPMs including E-core and C-core stator segments, 3) advanced thermal management using novel forced air and liquid cooling for the modular CPMs.
Firstly, the influences of winding configurations on the electromagnetic performances of fractional-slot (FS-) and integer-slot (IS-) CPMs are investigated. Based on the findings, the CPMs with different rotor structures including the surface-mounted permanent magnet (SPM), the I-shape interior permanent magnet (I-IPM) and the V-shape interior permanent magnet (V-IPM) are further investigated. Furthermore, the modular CPMs with both E-core and C-core stator segments are comprehensively investigated, which have potentially eased manufacture, assembly and transportation processes for large-dimension machines. The operating principle of the investigated modular CPMs are introduced based on mathematical modelling, and the phase back-EMF and electromagnetic torque production mechanisms have been analysed. Moreover, the static and dynamic performances such as on-load losses, torque-speed curves, power-speed curves and efficiency maps have been investigated for modular machines with different slot/pole number combinations.
Finally, to fully take advantages of the flux gaps (FGs), two forced cooling methods including forced air and forced liquid cooling are proposed for the modular CPMs. The FGs in the modular machines are utilized as extra cooling channels to improve the machine cooling efficiency. The effectiveness of both methods has been proven by the numerical results obtained by 3-dimentional computational fluid dynamics (CFD) analyses. Prototype machines including the conventional, E-core and C-core modular CPMs have been built, and the electromagnetic results obtained by finite element analysis (FEA) have been validated by a series of experiments. In addition, some design guidelines and recommendations are provided for machine designers to select the best modular CPMs for different applications having different requirements.