Axial flux surface mounted permanent magnet disc motors for smooth torque traction drive applications

Axial Flux surface mounted Permanent Magnet (AFPM) machines have gained growing interest during the last decade. These machines offer some unique features and have certain advantages over Radial Flux Permanent Magnet (RFPM) machines. This thesis investigates the surface mounted AFPM machines for smooth torque traction drive applications. It includes a detailed review of the possible slotless and slotted AFPM machines, sizing approach, and machine optimizations and comparison. The torque quality of each RFPM and AFPM machine has also been accomplished using both mathematical and Finite Element (FE) approaches. The results obtained from both Torque Ripple Factor (TRF) analysis and 2D/3D FEA are compared and illustrated in the thesis.; Cogging torque is very important issue for traction drive applications and no detailed cogging torque work has been done for AFPM motors. Cogging torque minimization techniques focusing on AFPM machines are reviewed and a new cogging torque minimization technique is introduced specifically for multiple rotor surface mounted AFPM motors. This new technique has not only some manufacturing advantages but also is very easy to implement. Basic principles of the new technique are explored and the proposed new method is applied to an AFPM machine. Cogging torque optimization using 3D FE analysis as well as minimum cogging torque is also accomplished.; Flux control capability is an important objective for PM machines. Unfortunately, surface mounted PM machines, by their nature, lack the capability to control the flux. A new Field Controlled Axial Flux surface mounted PM (FCAFPM) disc machine concept with field weakening capability for traction drive applications are introduced. Basic evaluation of the proposed topologies is attained and electromagnetic design of an 8-pole double-rotor-single-stator field controlled disc motor is presented. The sizing analysis, optimization, FE analysis, optimization of field weakening capability and torque capability have been the emphasis of the FCAFPM machine design. The prototype of the new FCAFPM machine is manufactured and tested in the lab. The theory has been supported with computer simulations and laboratory experiments, and strong correlation has been attained.