An elemental modelling method for linear motor parametric studies using boundary-free analytic magnetic field solutions: Including 3D geometry, permeability, and end effects

No-lapping concentrated windings permanent magnet linear synchronous motor (PMLSM) which possesses notable advantages such as big thrust force density, short winding head and small magnetic resistance is the preferred drive motor on Linear motor cordless upgrade system. In the paper 15 slots 16 poles PMLSM has been taken as example. On the basis of d-q dual-response theory, key parameters such as the motor resistance of q-axis (quadrature) and d-axis (direct) have been calculated by Finite Element Method. Thus mathematic model of PMLSM steady-state analysis has been built. PMLSM performances such as current, thrust force, power factor, efficiency, and electric power brake force affecting by supply voltage and ambient temperature change have been studied respectively both on load condition and no-load condition. The experiment results agree with theoretical analysis, with good prospects of permanent magnet (PM) linear synchronous motor for design and application of ropeless elevator.

A new transfer model vehicle system for automatic horizontal transport, especially in short-turning-area applications, has been developed in the authors' laboratory. It is driven by permanent magnet (PM) linear synchronous motors (LSMs), and can operate efficiently in orthogonally-crossed-guideway network in mass-reduced mode. This paper presents a fundamental study of the PM LSM vehicle running on such network guideways with two crossings. The experimental results have shown a good agreement of the vehicle motion with the demand pattern in network running operation.

There are produced the detent force caused by slot-teeth structures, end-effect and parallel magnetization of permanent magnet in permanent magnet linear synchronous motor. In this paper, we proposed to establish the auxiliary core for reducing detent force which is generated the discontinuity of magnetic circuits by end effect. The optimal design of the auxiliary core used a finite element analysis and design of experiment. To demonstrate the validity of the paper, the experiment results are compared with analysis ones.

The significant drawback of the permanent magnet linear synchronous motor (PMLSM) is force ripples, which are generated by the distortion of the stator flux linkage distributions, cogging forces caused by the interaction of the permanent magnet and the iron core and the end effects. This will deteriorate the performance of the drive system in high precision applications. The PMLSM and its parasitic effects are analyzed and modeled using the complex state-variable approach. To minimize the force ripple and realize the high precision control, the components of force ripples are extracted first and then compensated by injecting the instantaneous current to counteract the force ripples. And this method of the PMLSM system is realized by the field oriented control method. In order to verify the validity of this proposed method, the system simulations are carried out and the results are analyzed. The effectiveness of the proposed force ripples reduction method can be seen according to the comparison between the compensation and non-compensation cases.

Permanent magnet linear synchronous motors (PMLSM) offer several advantages over their rotary counterparts in many precision manufacturing applications requiring linear motion, which can achieve a much higher speed and a higher position accuracy. However, linear motors are more sensitive to disturbance and parameter variations. Furthermore, the linear motor systems are subject to significant nonlinear effects due to friction and force ripple. A sliding mode controller with an adaptive disturbance observer is processed to achieve high accuracy in the presence of external disturbance and parameter uncertainty. The position control for the gringding machine of a PMLSM feed drive using the proposed control strategies is illustrated. Simulation results show that the proposed controllers provide high-performance dynamic characteristics and are robust with regard to external load disturbance.

The end effect of the long primary permanent magnet linear synchronous motor (PMLSM) mainly comes from the breaking of the end permanent magnet field, which is a unique phenomenon and problem. This effect has a significant impact on the air-gap magnetic field and the electromagnetic parameters of the motor. Aiming at the end effect of the long primary PMLSM, this paper uses Schwarz-Christoffel transform to establish and solve the long primary PMLSM airgap magnetic field analysis model that takes into account the end effect, the expression of the additional magnetic field is obtained. Moreover, the equivalent circuit model of PMLSM considering the end effect is proposed based on the principle of equal field-circuit complex power, and the end effect reactance is obtained. Finally, the rationality of the end reactance was verified by the finite element numerical calculation, thus proving the validity of the equivalent circuit model that takes into account the end effect.

The winding segmented permanent magnet linear synchronous motor (WS-PMLSM) has not only a general slotting effect but also a unique two-end effect caused by the segmented stator and the finite length passive mover, which makes the detent force of WS-PMLSM possess the qualities of all types of linear motors. This paper adopts a physics-based multiple analytical method to study the detent force properties. First, an accurate sub-domain model is used to obtain the magnetic field distribution of the tooth slot, and the results of the analytical solution and the graph of the tooth slot effect are obtained using the scalar magnetic potential. Subsequently, the effect of the end unenergized core on the magnetic field is analyzed using Maxwell’s theory for the stator end effect, revealing that the end effect causes pulsating and reversing magnetic fields in the motor, which in turn creates mutual inductance with unequal phases, and generates thrust fluctuations. Finally, a complex relative air-gap permeability is introduced on the basis of the conformal mapping to equate the end effect generated by the permanent magnet. The accuracy of the proposed multiple analytical models was verified by the results of the finite element method (FEM) and experimental model.

This paper deals with the characteristics of permanent magnet linear synchronous motor according to the permanent magnet arrangement. The thrust, detent force, normal force and lateral force are generated in the permanent magnet linear synchronous motor. The detent force and lateral force cause the vibration of permanent magnet linear synchronous motor. The 3-D FEM is used to consider the effect of the skew and the overhang effect. Simulation values are compared with experimental ones. Furthermore characteristics of vibration and efficiency are estimated by experiments.

Linear motor eliminates the middle part of mechanical drive train, but because of structural characteristics of itself, must to take effective measures to reduce thrust fluctuations, or direct drive will lost its original meaning. In this paper, firstly research on detent force of moving magnet type permanent magnet synchronous linear servo motor and analyze the principle of generate detent force, secondly analyze the cogging force of moving magnet type permanent magnet synchronous linear motor and obtain the expression of cogging force maximum value, finally propose effective method to reduce detent force.

Permanent magnet linear synchronous motor (PMLSM) has important applications in transportation and industrial control systems for its direct thrust and high power density, etc. Thrust and normal force are the most important criteria for the PMLSM, and numerical methods and finite element analysis (FEA) methods have been conduced to evaluate the forces. In this paper, a prototype has been built to measure the thrust and the normal force of a PMLSM Through investigations with experiments, the traits of the thrust and the normal force have been found out, including the trends versus exciting currents with different amplitudes, different air gap lengths, variable magnetic poles, and different magnet arrangements. Conclusions are drawn through experimental analysis benefit to the electromagnetic design and control scheme evaluation for the PMLSM.

Permanent magnet linear synchronous motor (PMLSM) has a good application prospect in the fields of electromagnetic emission. The finite element method is applied to analyze the magnetic field of PMLSM with different permanent magnet (PM) structures. Then, the thrust characteristic of the PMLSM is optimized by PM cutting and Halbach PM, which promotes the study of permanent magnet structure problems in the design of PMLSM.

In this paper, a technique for reducing the cogging force in slotted permanent magnet linear synchronous motors (PMLSMs) is presented. A two-step minimization process that depends on the slotting and end effects is proposed. Taguchi's parameter method, coupled with 2-D and 3-D finite element analysis (FEA), is employed to minimize the cogging force.

This paper compares three possible linear motor topologies for an electromagnetic launch system to assist civil aircraft take-off. Assisted launch of civil aircraft has the potential of reducing the required runway length, reducing noise and emissions near airports and improving overall aircraft efficiency through reducing engine thrust requirements. A comparison is made of practical designs of a linear induction motor, a linear permanent magnet synchronous motor and a superconducting linear synchronous motor to propel the A320-200 aircraft. The machine design requirements are established considering aerodynamic and engine performance and allow the aircraft to safely complete the take-off procedure. Analytical design of conventional synchronous and asynchronous linear motor will be compared with finite element analysis. A superconducting synchronous motor design is also considered, accounting for full system losses including the cryocooler power requirement and the mechanical & design constraints necessary for the cooler and the superconducting coils.

In material handling applications where high precision, very long tracks and closed paths are required, short primary linear drives are proposed. The short primary type uses an active vehicle (moving winding) on a passive track (stationary magnets or induction rail). To implement this topology, this paper presents a combined operation of a short permanent magnet linear synchronous motor (PMLSM) and a linear induction motor (LIM). The costs can be reduced considerably by using a simple induction rail, instead of permanent magnets on the track. The control unit and converters are mounted on board of the active vehicle. A contactless energy transmission provides the average power and an ultracapacitor bank provides the peak power demanded by the active vehicle via a bidirectional DC-DC converter. The field oriented control, the drive control, the machine model and the control structure are based on field oriented control (FOC) using the rotating AB-reference frame. The transition control strategy is described and experimental results demonstrate the transition between sections with permanent magnets and induction rail.

A discontinuity of magnetic circuits according to the end effect is generated in the permanent magnet linear synchronous motor (PMLSM). Due to the unbalanced back electro-motive force (EMF) and impedance produced, unbalanced current is generated. The circulating current, which is caused by a decrease in the thrust, is generated by the unbalanced current. The optimal design of auxiliary-teeth at the end of the mover was carried out to solve the unbalance of phase by using design of experiment (DOE), and compared with the basic model through finite element analysis (FEA). As a result, the auxiliary-teeth model compensates for the decrease of thrust caused by the unbalanced phase. Also, this model is proven to reduce the detent force by the vibration and noise of the PMLSM and copper loss caused by the circulating current.