Four-Pole Hybrid Magnetic Bearing

Magnetic bearings, with their advantages of no friction and wear, low noise, cleanliness, and no need for lubrication, have irreplaceable unique benefits compared to traditional mechanical bearings, and hold broad application prospects. Building on the existing three-pole and six-pole magnetic levitation bearings, this paper mainly designs a four-pole radial-axial hybrid magnetic bearing, primarily applied to high-speed, high-precision milling electric spindles. This includes optimizing the magnetic circuit structure of the four-pole magnetic bearing and obtaining the levitation force through its equivalent magnetic circuit diagram. A model is established based on design parameters and verified through finite element simulation. In terms of control, state feedback and LQR feedback replace the traditional PID control.