6McMullen P T.S.Huynh C.Hayes R J.Combination radial-axial magnetic beating[C].In.Proc.6th Int.Symp.Magnetic bearings,ETH Zurich,Switzerland,2000:473-478.
7Schweitzer.G.Traxler A.Bleuler.H.Active Magnetic Bearings.Spring-Verlag Berlin.Heidelberg,1993.