Control Designs for Low-Loss Active Magnetic Bearing: Theory and Implementation

GCFC;Generalized complementary flux condition;Flux Bias, Nonlinear Control;Flywheel battery;Magneic bearings

Wilson, Brian Christopher David ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: GCFC;    Generalized complementary flux condition;    Flux Bias, Nonlinear Control;    Flywheel battery;    Magneic bearings;   

Others  :  https://smartech.gatech.edu/bitstream/1853/5228/1/wilson_brian_c_200405_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Control Designs for Low-Loss Active Magnetic Bearings: Theory and Implementation Brian C. D. Wilson327 Pages Directed by Dr. Panagiotis Tsiotras and Dr. Bonnie Heck-FerriActive Magnetic Bearings (AMB) have been proposed for use in Electromechanical Flywheel Batteries. In thesedevices, kinetic energy is stored in a magnetically levitated flywheel which spins in a vacuum. The AMB eliminates all mechanical losses, however, electrical loss, hich is proportional to the square of themagnetic flux, is still significant. For fficient operation, the flux bias, which is typically introduced into the electromagnetsto improve the AMB stiffness, must be reduced, preferably to zero. This zero-bias (ZB) mode of operation cripples the classical control techniques which are customarily used and nonlinear control is required. As a compromise between AMB stiffness and efficiency, anew flux bias scheme is proposed called thegeneralized complementary flux condition(gcfc). A flux-bias dependent trade-off exists between AMB stiffness, power consumption, and power loss. This work theoretically develops andexperimentally verifiesnew low-loss AMBcontrol designs which employ thegcfc condition. Particular attention is paid tothe removal of the singularity present in the standard nonlinear control techniques when operating in ZB. Experimental verificationis conduced on a 6-DOF AMB reaction wheel.Practical aspects of the gcfc implementation such as flux measurement andflux-biasimplementation with voltage mode amplifiers usingIR compensation are investigated. Comparisons are made between the gcfc bias technique and the standard constant-flux-sum (cfs) bias method. Under typical operating circumstances, theoretical analysis and experimental data show that the new gcfc bias scheme is more efficient in producing the control flux required for rotor stabilization than the ordinary cfs bias strategy.