Low Loss and Low Cost Active Radial Homopolar Magnetic Bearing

This paper describes an analytical modeling of a new magnetic bearing with an additional permanent magnet circuit. The suggested design offers various advantages opposite conventional magnetic bearings with regard to the mechanical and electrical expenditure. Using additional permanent magnet circuits the possibility is offered to reduce the required drive power, which is necessary to obtain the radial carrying forces. A simple drive with conventional three-phase current power amplifier becomes practicable. The calculation, design and optimization of the permanent magnetic and electromagnetic circuits is realized by technical and economical point of view. The theoretical executions are concentrated on the calculation of the magnetic forces and the investigation of the coupling of the x- and y-axis. Pure analytical methods are used for this purpose. On the strength of the special arrangement of the stator rings there is a linearization and decoupling of the force characteristics. For the control behavior it leads to, that for example a stabilization of a disturbance force in x-direction causes a negligible force change in the y-axis. At this style there is nearly no coupling of the rotor position. All these influences are shown in diagrams and discussed in detail.