Eddy Currents in the Rotor Shroud and Permanent Magnets of High-Speed Electrical Machines

This paper examines the electromagnetic processes created by eddy currents in the rotor shroud and in the permanent magnets of high-speed electrical machines with a tooth-coil winding and high-coercivity permanent magnets. To estimate the influence of eddy currents, computer modelings of the electrical machines were made using the Ansys Maxwell software package. Losses and magnetic fields created by eddy currents were examined by these computer models. The harmonic composition of currents and voltages induced by eddy currents was investigated. It was found that the magnetic fields created by the eddy currents in the rotor shroud and the permanent magnets lead to the appearance of even harmonics in the output voltage and current of the electrical machine. To confirm the results of the computer simulation, an experimental study was carried out.