Ultra High Speed Motor Supported by Air Foil Bearings for Air Blower Cooling Fuel Cells

As accomplishing the research of the PM synchronous motor driven by 15 kW at the rated speed of 120,000 rpm, this paper represents an approach to minimize eddy current losses which occur prominently at high speed. Various simulation and testing techniques are therefore applied to determine the effect of design parameters. Here, the proposed parameters for analysis are winding types, slot opening width and sleeve thickness. This paper based on the obtained results, evaluates the optimum value of the most critical design parameters responsible for eddy current loss. Finally, this paper studies the developed model which represents a solution for minimizing the cause of eddy current loss by implementation of sinusoidal distribution of air-gap magnetic flux density. It comes to the conclusion that sleeve thickness should be chosen as considering a function of mechanical stress and critical speed of rotor. Furthermore, the critical speed of rotor is evaluated by rotor dynamics. The design efficiency is well accorded with the efficiency test, having a maximum error of 2.7%.