VP11-12 Design and Implementation of Fixed-bias Flux 3-Phase Magnetic Bearing
Creators: Sujin Noh
Joo Hong Park
Dayoung Lee
Sang-Il Byun
Han-Wook Cho
Publisher: name: IEEE
Year: 2025

This paper presents the design and experimental results of a magnetic bearing system that employs permanent magnets part as a fixed-bias flux and incorporates a three-phase electromagnet part to maintain the rotor's central position. Magnetic bearings (MB) offer numerous advantages over traditional contact bearings, including lubrication-free operation, no wear, and extended lifespan due to their contactless nature [1-4]. Conventional hybrid magnetic bearings typically control the rotor position through differential control of bias flux generated by permanent magnets and control current from electromagnets. However, this approach does not fully utilize the force of the permanent magnets. To address this limitation, the proposed design maximizes the utilization of permanent magnet force. Additionally, magnetic bearings that use a three-phase winding system require fewer circuit components compared to those operating with a single-phase full-bridge converter. Therefore, a 12-pole heteropolar magnetic bearing connected in a three-phase arrangement is placed at the top and bottom to enable radial position control. The electromagnetic characteristics of the proposed model were analyzed using an equivalent magnetic circuit modeling approach. Specifically, the study examined the relationship between the rotor's eccentricity. Fig. 1. shows the magnetic flux density in the permanent magnet region for rotor eccentricities of 0.1 mm, 0.3 mm, and 0.5 mm along the x-axis. Precise force calculations were performed based on the calculated magnetic flux density, and the results were compared and validated with three-dimensional(3-D) finite element analysis (FEA). Based on this analysis, comprehensive system force modeling was conducted. Subsequently, a 3-D mechanical design was performed to develop manufacturing plans and the experimental setup. Fig. 2. shows the fabricated electromagnet part of the system. Using a digital signal processing (DSP) microcontroller and other low-cost electronic components, experimental tests were conducted.References: [1] N. R. Hemenway and E. L. Severson, "Three-Pole Magnetic Bearing Design and Actuation," IEEE Trans. Ind. Appl., vol. 56, no. 6, pp. 6348-6359, Nov.-Dec. 2020. [2] X. Sun, L. Chen and Z. Yang, "Overview of Bearingless Permanent-Magnet Synchronous Motors," IEEE Trans. Ind. Electron., vol. 60, no. 12, pp. 5528-5538, Dec. 2013. [3] H. Sugimoto, Y. Uemura, A. Chiba and M. A. Rahman, "Design of Homopolar Consequent-Pole Bearingless Motor With Wide Magnetic Gap," IEEE Trans. Magn., vol. 49, no. 5, pp. 2315-2318, May 2013. [4] W. Zhao and L. Mei, “Reseach on Modular Permanent Magnet Bias Magnetic Bearing,” J. Electr. Eng. Technol., vol. 17, pp. 3283-3296, Aug. 2022.
This paper presents the design and experimental results of a magnetic bearing system that employs permanent magnets part as a fixed-bias flux and incorporates a three-phase electromagnet part to maintain the rotor's central position. Magnetic bearings (MB) offer numerous advantages over traditional contact bearings, including lubrication-free operation, no wear, and extended lifespan due to their contactless nature [1-4]. Conventional hybrid magnetic bearings typically control the rotor position through differential control of bias flux generated by permanent magnets and control current from electromagnets. However, this approach does not fully utilize the force of the permanent magnets. To address this limitation, the proposed design maximizes the utilization of permanent magnet force. Additionally, magnetic bearings that use a three-phase winding system require fewer circuit components compared to those operating with a single-phase full-bridge converter. Therefore, a 12-pole heteropolar magnetic bearing connected in a three-phase arrangement is placed at the top and bottom to enable radial position control. The electromagnetic characteristics of the proposed model were analyzed using an equivalent magnetic circuit modeling approach. Specifically, the study examined the relationship between the rotor's eccentricity. Fig. 1. shows the magnetic flux density in the permanent magnet region for rotor eccentricities of 0.1 mm, 0.3 mm, and 0.5 mm along the x-axis. Precise force calculations were performed based on the calculated magnetic flux density, and the results were compared and validated with three-dimensional(3-D) finite element analysis (FEA). Based on this analysis, comprehensive system force modeling was conducted. Subsequently, a 3-D mechanical design was performed to develop manufacturing plans and the experimental setup. Fig. 2. shows the fabricated electromagnet part of the system. Using a digital signal processing (DSP) microcontroller and other low-cost electronic components, experimental tests were conducted.References: [1] N. R. Hemenway and E. L. Severson, "Three-Pole Magnetic Bearing Design and Actuation," IEEE Trans. Ind. Appl., vol. 56, no. 6, pp. 6348-6359, Nov.-Dec. 2020. [2] X. Sun, L. Chen and Z. Yang, "Overview of Bearingless Permanent-Magnet Synchronous Motors," IEEE Trans. Ind. Electron., vol. 60, no. 12, pp. 5528-5538, Dec. 2013. [3] H. Sugimoto, Y. Uemura, A. Chiba and M. A. Rahman, "Design of Homopolar Consequent-Pole Bearingless Motor With Wide Magnetic Gap," IEEE Trans. Magn., vol. 49, no. 5, pp. 2315-2318, May 2013. [4] W. Zhao and L. Mei, “Reseach on Modular Permanent Magnet Bias Magnetic Bearing,” J. Electr. Eng. Technol., vol. 17, pp. 3283-3296, Aug. 2022.