Design, Analysis And Control Of A 5-Phase Fractional Slot Surface Mounted Pm Machine For Applications With A Wide Speed Range

Reliability problems associated with a three-phase electrical machine lead the researcher to investigate multi-phase machines, where the number of phases is greater than three, and which are starting to attract a growing interest. A five-phase surface mounted permanent magnet synchronous motor (SPM) can be considered as a candidate for fault-tolerant critical applications such as electrical actuators in aircraft and aerospace applications, in addition to other characteristics like high torque-tomass ratio and high effciency. This thesis is concerned with the design, analysis and control of a five-phase SPM machine equipped with a fractional slot winding. In particular, it examines the possibility of using five-phase SPM machines for fault tolerant, wide speed range applications. The thesis covers three sub-areas. The first describes the design, analysis and test of a five-phase SPM motor with improved capability in fault event and uxweakening operation. A five-phase SPM motor has been designed by deriving all necessary equations required for optimising the machine to produce an acceptable torque at high operating speeds above the corner speed. The second aims to explore the effect of varying the motor drive parameters on the optimum ux-weakening performance of the Multi-Frequency (MF) five-phase SPM drive. It is shown that the fundamental magnet ux linkage determines the maximum reachable speed in the ux-weakening mode of operation. The back-emf ratio increases the normalised electromagnetic torque for speeds below the base speed, while it decreases the normalised electromagnetic torque for speeds higher than the base speed. The third deals with the modelling and control of five-phase PM synchronous machines with a non-sinusoidal shape of the rotor ux. A discrete PI controllers for currents and speed were designed based on the two virtual machines analysis. The simulation and practical results showed a good dynamic response.