Structural Analysis Of Induction Power Magnetic Bearing And Design Of Axial Loading Platform

Power Magnetic Bearing is also called Bearing-less Motor and its stator is composed of torque winding which outputs torque and suspension winding which outputs magnetic levitation force. Although the winding theory about general AC machine is mature, there is lack of relevant theoretical basis that can confirm the number of wire per slot of two windings of Power Magnetic Bearing.Basic steps about structural design to Power stator of Magnetic Bearing is generalized after analyzing and comparing the nature characteristics between Power Magnetic Bearing and general AC machine. Matching relation about the number of wire per slot of two windings is deduced and powers of two windings are calculated by utilizing conservation of energy principle.A winding of general AC machine is changed into a one of Power Magnetic Bearing by utilizing the relation, that the number of wire per slot of two windings, and finite element analysis is implemented to the magnetic field of the Power Magnetic Bearing. It turns out that the stator dimensions which are determined by the electromagnetic parameters of former motor limit the increase of power of Power Magnetic Bearing. Therefore a measure to increase the height of the stator yoke is put forward to counter balance the power loss. It shows that Power Magnetic Bearing with improvement has a higher magnetic flux density of air-gap through theoretical arithmetic and electromagnetic field analysis. It means that the power of Power Magnetic Bearing increases.A mathematic model of Electromagnetic force and an axial motion control equation of rotor is deduced under differential state of Thrust Magnetic bearing by utilizing balance equation of stator voltage, motion equation of Thrust collar and fundamental law of magnetic circuit. A closed loop transfer function block diagram in which stator voltage is used as a control variable is designed. This diagram establishes a theoretical basis for the design of control circuit and the setting of control variable.In order to test the mechanical property and control system of Thrust Magnetic bearing, a set of loading experimental platform is designed. This platform contains support device and force device, and its reliability is analyzed by finite element method.