Improved design of Lorentz force-type magnetic bearings for magnetically suspended gimballing flywheels

A Lorentz force-type magnetic bearing (LFMB) with good linearity is suitable for the high-precision deflection control of a magnetically suspended gimballing flywheel (MSGFW). In this paper, a novel LFMB with improved double magnetic circuits is presented. Inclined magnetization Halbach array permanent magnets (PMs) and trapezoidal PMs are utilized for improving the magnetic flux density. A mathematical model of the magnetic flux density is established based on the equivalent surface current method. To obtain the maximum magnetic flux density, the optimal magnetization angle is calculated, and the dimension parameters are optimized by the sequential quadratic programming method. A maximum magnetic flux density of 0.615 T is obtained, which is 7.9% larger than that of an LFMB with conventional double magnetic circuits. Based on simulation results, LFMB prototype magnetic flux density experiments are carried out. The results show that the magnetic flux density fluctuations of the two LFMB schemes are similar. The maximum magnetic flux density of 0.608 T is increased by 6.7% when compared with that of the LFMB with conventional double magnetic circuits at 0.57 T. The error between the simulation and the experiment is within 5%. This indicates that the LFMB with improved double magnetic circuits is promising when it comes to meet the agile maneuver requirements of the spacecraft.