Search

Bearingless switched reluctance motor (BSRM) adopts a doubly salient structure without windings on the rotor. BSRMs have the advantages of high rate of fault tolerance and simple structure, high power, super high speed and strong adaptability. They have broad application prospects in aerospace, flywheel energy storage, new energy and biomedical fields. Firstly, the suspension operation mechanism of a conventional double winding BSRM is described in this paper. The coupling between torque and suspension force is analyzed with a finite element method. On this basis, from the perspective of magnetic circuit optimization of the torque system and suspension system, the magnetic circuit design, decoupling mechanism and performance characteristics of self-decoupled BSRMs with different topological structures are described centering on the self-decoupled topology form of the BSRM. Finally, the study and development of BSRMs in the future are prospected based on the research status.

High integration, low loss and high-reliability are the main development trends of flywheel battery. Thus this study presents the first prototype of a novel high-integration four degrees of freedom (4-DOF) bearingless motor with the advantages of weak coupling and low power consumption. The proposed bearingless motor can realize energy conversion and produce 4-DOF radial forces compared with the conventional bearingless motor for improving the integration of system. A biased flux for producing radial levitation forces is provided by the permanent magnets, which reduce the power consumption of the system. Moreover, a decoupling between the torque and the suspension systems is realized through a structural design, thereby improving the controllability. Structure and winding configurations are introduced and the operation principle of the 4-DOF bearingless motor is discussed. Magnetic circuits analysis and parameter design method are present and a three-dimensional finite element model is established. Electromagnetic characteristics that focus on the high integration, low loss and high reliability are discussed and validated comprehensively. Finally, a favorable controllability of radial suspension forces are verified using finite-element analysis and some experimental results.

Mathematical models are disappointing due to uneven distribution of the air gap magnetic field and significant unmodeled dynamics in magnetic bearing systems. The effectiveness of control deteriorates based on an inaccurate mathematical model, creating slow response speed and high jitter. To solve these problems, a model-free adaptive control (MFAC) scheme is proposed for a three-degree-of-freedom hybrid magnetic bearing (3-DoF HMB) control system. The scheme for 3-DoF HMB depends only on the control current and the objective balanced position, and it does not involve any model information. The design process of a parameter estimation algorithm is model-free, based directly on pseudo-partial-derivative (PPD) derived online from the input and output data information. The rotor start-of-suspension position of the HMB is regulated by auxiliary bearings with different inner diameters, and two kinds of operation situations (linear and nonlinear areas) are present to analyze the validity of MFAC in detail. Both simulations and experiments demonstrate that the proposed MFAC scheme handles the 3-DoF HMB control system with start-of-suspension response speed, smaller steady state error, and higher stability.

A hybrid double stator bearingless switched reluctance motor with advantages of high suspension output, small loss and weak coupling is presented. This motor can realise electric/power generation and radial two-degree-of-freedom suspension. The biased magnetic field for producing radial force is provided by a permanent magnet, which reduces system power consumption. Self-decoupling is realised between a torque system and suspension system according to the mechanical structure design. Furthermore, the radial force is approximately constant when the suspension current is constant, thereby improving the controllability of the system. The operation principle is introduced and the electromagnetic characteristics are analysed through the time-stepping finite element method. This analysis verifies the effectiveness of the theoretical analysis.

This paper presents a new decoupling control strategy for a 12/8 bearingless switched reluctance motor (BSRM) with improved mathematical model. Firstly, the improved mathematical model is built by Maxwell stress tensor method selecting one-forth arc integration path of the fringing magnetic field. Then, a new decoupling control strategy is described. The average torque and radial force of the scheme is decoupled and the utilization of current is enhanced. Finally, finite element analysis (FEA) model under this control strategy is established, and simulation results verify that the proposed mathematical model and control strategy are effective.

The least square support vector machine (LS-SVM) inductance model optimized by the particle swarm optimization (PSO) algorithm is presented for bearingless switched reluctance motor (BSRM). The training sample is first obtained using the 3D finite element model (FEM) of the prototype, and then LS-SVM model is built, whose hyper-parameters are optimized using PSO algorithm. The absolute error and relative error are computed, which demonstrate the high accuracy of the proposed model.

On the basis of empirical study of the logistics of 13 enterprises in Sichuan Province, this paper has studied the impact of job satisfaction and organizational commitment on contextual performance. The results demonstrated that the higher the pay satisfaction is, the more obvious the staffs' interpersonal facility, (the coefficient is 0.713); the higher normative commitment is, the more obvious interpersonal facility, (the coefficient is 0.686); job dedication is not only influenced by pay satisfaction and supervisor satisfaction (path coefficients is 0.658 and 0.669 respectively), but also by the continuing commitment and normative commitment (path coefficients is 0.717 and 0.682 respectively). On the basis of these findings, a few valuable suggestions surface for the improvement of contextual performance in enterprise logistics.