Bearingless motor's radial suspension force control based on virtual winding current analysis

Abstract

Decoupling control of torque and suspension force is the key technology to achieve stable operation for bearingless motors. In this paper, after a general introduction of the principle of radial suspension forces for the bearingless permanent magnet synchronous motor (BPMSM), a new analysis method based on virtual winding current is presented. Based on the proposed analysis method, the corresponding theoretical analysis of suspension operation is presented. Meanwhile, the control strategy of stable operation is put forward for the BPMSM. In order to testify the validity of the proposed analysis method, the relevant experiments are designed and conducted. It can be concluded that the experiment results are very close to theoretical analyses based on the proposed method. Moreover, the validity of control strategy can be confirmed, which establishes foundations for further research.

Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

“…In conclusion, the direction of radial suspension force rotation has relations with that of equivalent suspension force winding rotation, and the rotating angular velocity is PB times to that of equivalent suspension force windings, as can be seen in [16]. The description of the principle for the 2-4 poles BPMSM also applies to other pole pair compositions and various types of bearingless motors.…”

A Novel Single Winding Structure and Closed Loop Control of the Suspension Force Vector of Bearingless Permanent Magnet Synchronous Motors

“…i stU1 " I s cospωtq`I t cospωtq i stV1 " I s cospωt´2π{3q`I t cospωt´2π{3q i stW1 " I s cospωt`2π{3q`I t cospωt`2π{3q i tU2 " 2I t cospωt´πq i tV2 " 2I t cospωt´π{3q i tW2 " 2I t cospωt`π{3q (2) where i st(U~W)1 is the winding current supplied by the first inverter, i t(U~W)2 is the winding current supplied by the second inverter. Both the original and improved winding topologies of the motor structure are shown in Figures 2 and 3.…”

“…Conventional BPMSMs require two sets of stator windings: the torque winding and the suspension force winding, sharing the same stator slots to simultaneously generate torque and suspension forces. There inevitably exist the problems of making the motor size larger, processing process complexity and increased power consumption [2]. The magnitude of the suspension current required during normal operation is low, which results in insufficient utilization of the suspension winding which can provide sufficient suspension force under the maximum allowable eccentric displacement, further spread and application of BPMSMs has been hindered [3].…”

A Bearingless Induction Motor Direct Torque Control and Suspension Force Control Based on Sliding Mode Variable Structure

“…For the part of suspension force control, the traditional method is by detecting the radial displacement of the rotor, and the given value of suspension force is obtained by the PID modulation, which can realize the closed-loop control of the suspension force [17]. The method is relevant to air gap flux identification, and its dynamic response and the anti-interference performance are not good.…”