Design and evaluation of a 300 kW double stage axial-flux permanent magnet generator

[摘要] ENGLISH ABSTRACT: This thesis deals with the design and evaluation of a 300 kW double stage axial-fluxpermanent magnet generator with an ironless stator. The magnetic and electricaldesign equations are derived for sinewave and quasi-squarewave axial-flux permanentmagnet machines. The thermal design approach used is also described. The machineis optimised for maximum torque per current loading. A Matlab program code isdeveloped to do the necessary calculations in the design optimisation and thecalculation of the machine parameters.Mechanical finite element simulations are conducted to investigate the severity of themagnetic attraction force between the rotor discs. The results obtained from thesimulations suggested an increase in the yoke thickness in order to withstand theattraction force. The construction of the prototype machine's rotor and stator isdescribed. The flux density in the airgap is thoroughly investigated throughmeasurements and analysis. Thermal measurements are also conducted to investigatethe effect of eddy currents in the stator winding. Furthermore, no-load measurementsconducted on the 300 kW machine showed that the machine has a serious problem ofcirculating currents in the parallel connected coils. Possible solutions for this areinvestigated and recommendations are given. Due to the circulating current problemand the relative high eddy current losses, it was not possible to do full-load tests onthe machine.

[发布机构] Stellenbosch University