Research On Bearingless Switched Reluctance Generators

The bearingless switched reluctance motor(BSRM) has been the focus research since 1990's. It takes advantage of radial forces generated in the rotational process to suspend the rotor. And it also provides a new approach to solve the problems of switched reluctance motor's (SRM's) noises and vibration. So the application field of SRM is broadened.This dissertation focuses on the basic theory of bearingless switched reluctance generators(BSRGs). The main contents are as follows:The mathematical model of BSRMs with single-phase excitation is analyzed. The basic theory of switched reluctance generators(SRGs) is illustrated.By analyzing the control strategies of SRG, three control strategies of BSRGs are suggested: current chopping control(CCC), angle position control(APC), pulse width modulation(PWM). The performances of two control strategies which are CCC and PWM are investigated in Matlab/Simulink. Simulation results verify the feasibilities of the two control schemes.In terms of the key to the control system, the hardware system is designed including main winding converter, radial force winding converter, driving circuit, snubbers, protect circuits and signal regulator.Finally, a novel scheme of bearingless switched reluctance motors with two-phase excitation is proposed. A mathematical model is built based on two-phase excitation. With comparing two-phase excitation mode to single-phase excitation mode, the operating area of two-phase excitation mode is expanded to a great extent. Two optimal methods to distribute currents of two-phase windings including main windings and radial force windings for practical applications are also proposed.