Design And Simulation On The Power Amplifier Of Active Magnetic Bearings

Active Magnetic Bearings (AMB), which use controllable electromagnetic force to support freely a rotor, have a lot of advantages such as adjustable stiffness and damp that the traditional bearings can't compare with, so it is called a technique revolution in the bearings.Power amplifier is a crucial part in the AMB control system. It is used to magnify or convert the control signal into a power signal with enough energy to drive the electromagnetic iron actuators. So the performance of power amplifier plays an important role in the technique capability of control system.Considering the characteristics of AMB, ordinary power amplifier can not meet the demand in its control system, so high-performance and high-efficiency power amplifier, most of which should design exclusively, is needed here, and moreover the design is full of difficulty and complexity.Therefore, this dissertation has made a research on the power amplifier of the AMB, the main work is arranged as follows:In order to make preparation for the analysis of the power amplifier, the system composing of the AMB is introduced at first, and then detailed mathematics description which is based on a 1DOF AMB system is analyzed;From four kinds of amplifier models, a very clear analysis to the basic theories of the AMB power amplifier is made based on the current mode switching power amplifier, and the detailed structure of switching power amplifier is discussed then, four category of the switching power amplifier is presented subsequently;Because the PWM power amplifier is widely applied at present, so the implementation of the PWM modulator is discussed, a design example of the PWM power amplifier is put forward, and several kinds of new switching power amplifier based on the PWM technique are introduced;Two simulation software MATLAB\Simulink and MultiSIM, which have the special features between each other, are introduced. A three-level PWM switching power amplifier and a current mode three-level switching power amplifier are designed and simulated respectively through the two simulation software, moreover the author's own analytical views are put forward.At last, based on the summary of this dissertation, the developing trend of the power amplifier in the AMB is prospected.