Research On Speed Sensorless Technology For Bearingless Induction Motor

Bearingless motors,which combine magnetic levitation bearings with the drive winding,have the advantages of no abrasion,no lubrication and no particle generation caused by bearings.Furthermore,in comparison with conventional magnetic bearing motors,the axial length of the rotor is decreased,which results in increased frequency of the mechanical natural vibration.Furthermore,the efficiency can be increased because the magnetic flux of the motor can be partly used for levitation.When the bearingless induction motor works in high or super high speed,obtain of the rotor speed information becomes difficult.Then the speed sensorless technology can be applied to get the speed information. Until now,a lot of work has been done on the technology.This dissertation focuses on the main theory of the speed sensorless technology in the vector control of the bearingless induction motor.In this dissertation,the mathematical models of the bearingless induction motor are derived and the rotor flux orientation vector control system of the bearingless induction motor is analyzed.Based on the above points,this dissertation mainly studies on the high-frequency signal injection and model reference adaptive system.At the same time,two methods is validated by the computer simulation in different speeds.At last,the digital control system is designed.the application of the speed, sensorless technology in the vector control of the bearingless induction motor is coming true.A digital control system for real-time control is designed on DSP (TMS320F2812).Moreover,the main design schemes of the software and hardware are introduced in detail.Test results in a prototype motor validate the performance efficiency.