Influence of using conditions on the performance of PM linear synchronous motor for 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.

Thrust performance is one of the important indexes of permanent magnet linear synchronous motors. The traditional non-oriented silicon steel sheet is used as the core material of the permanent magnet linear synchronous motor, which limits the performance of the permanent magnet linear synchronous motors. For the oriented silicon steel sheet has a higher magnetic permeability in the rolling direction, a permanent magnet linear synchronous motor with similar number of poles and slots made of oriented silicon steel is proposed in this paper. By measuring the B-H curves of the rolling direction and the cutting direction, the thrust properties of the two motors made of traditional silicon steel sheets and oriented silicon steel sheets are analyzed and compared by the finite element method (FEM) under rated load and overload conditions respectively. The thrusts under different tooth-yoke ratios are discussed in the end.

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 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.

The permanent magnet linear synchronous motors (PMLSM) are proposed for many applications ranging from ground transportation to reciprocating servo system and conveyance system for their simple structure and high performance. Generally, the acceleration and deceleration experiment of PMLSM is very difficult because it has restricted limits of operating. Therefore, this paper proposes disk type PMLSM in order to solve problem stated above. Since the proposed disk type PMLSM has infinite operation limits, it can be solved a problem in acceleration and deceleration experiment of PMLSM. This paper also deals with the analysis of disk type PMLSM considering slot opening and skew effect for a various air-gap length, in terms of air-gap flux density and 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.

Reduction of the spatial harmonics of back electromotive force(EMF) is a useful way to reduce thrust ripple of permanent magnet linear synchronous motor (PMLSM). In this study, a method of v-skewing in the coils is proposed to reduce the harmonics to suppress thrust ripple in the PMLSM. The thrust and the harmonic are generated in a double-sided PMLSM model. The 3-D finite element method (FEM) is used to build the PMLSM model in consideration of the effect of the v-skewing. Motor platform and testing platform are also built to conduct experimental verification. Simulation results are compared with experiment values. The results indicate that the proposed method is effective for reduction of thrust ripple in double secondary PMSLM.

An automated commissioning procedure is proposed to tune the electrical and mechanical parameters of a linear surface-mounted permanent magnet synchronous motor drive, which is under vector control. The key tuning technique is to utilize a measure on the degree of distortion of controller output waveforms, which is developed from the first-order Walsh function series coefficient. The controller parameters are subsequently tuned based on the identified parameters and the pole-placement technique. An experimental prototype is implemented to test the validity of the proposed approach. Simulation and experimental results confirm the effectiveness of the proposed method in commissioning the vector-controlled linear permanent magnet synchronous motor drives.

Because of the uncertainty’s action in a linear permanent magnet synchronous motor drive system such as the external load force, the cogging force, the column friction force and the Stribeck effect force and the parameters variations, it is difficult to reach specific control performances by using the existing linear controller. To raise robustness under occurrence of parameters uncertainties and external force disturbances, the smart backstepping control system with three adaptive laws is proposed for controlling the linear permanent magnet synchronous motor drive system. In accordance with the Lyapunov function, three adaptive laws are derived to ameliorate the system’s robustness. Furthermore, the smart backstepping control system using revised recurrent fuzzy neural network and revised ant colony optimization with the compensated controller is proposed to improve the control performance. The revised recurrent fuzzy neural network acts as the estimator of the uncertainty’s disturbances. In addition, the compensated controller with error estimation law is proposed to compensate the minimum rebuilt error. Moreover, two learning rates of the weights in the revised recurrent fuzzy neural network are derived according to the discrete-type Lyapunov stability to assure convergence of the output tracking error and are adopted by using the revised ant colony optimization to speed-up parameter’s convergence. Finally, some comparative performances are verified through some tentative upshots that the smart backstepping control system by virtue of revised recurrent fuzzy neural network and revised ant colony optimization with the compensated controller results in better control performances for the linear permanent magnet synchronous motor drive system.

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.

In order to analyse the electromagnetic field of the permanent magnet linear synchronous motor, the wavelet finite element method is applied to compute the electromagnetic field of it. First, the basic theory of Daubechies' wavelet is studied. Then the wavelet finite element model of the electromagnetic field of permanent magnet linear synchronous motor is constructed. Then simulation analysis of electromagnetic field is carried out by the wavelet finite element method, the traditional finite element method and actual test. And simulation results show that the wavelet finite element method has better convergence and can use fewer wavelet finite elements to get the higher computing precision for computing the electromagnetic field of the permanent magnet linear synchronous motor.

The severe drawback of slotted permanent magnet linear synchronous motor (PMLSM) is the detent force, particularly when accurate positioning and constant low speed is required for numerically controlled machine tool. In this paper, a novel short-armature slotted type multi-segment permanent magnet linear synchronous motor (MSPMLSM) is proposed and constructed to reduce the detent force. It consists of a proper shift of the multiple segments of iron core relative to the PMs. The detent forces of MSPMLSMs with different number of segment are analyzed and simulated by finite element method (FEM). The proposed structure has been proved to be a very effective approach for the reduction of detent force. Then this paper presents the statistical and mathematical optimum design of a 3-segment PMLSM using response surface methodology (RSM) together with FEM to minimize the detent force. Full factorial design and steepest ascent method, one of the iterative search method, is proposed to establish optimal design area for applying RSM. Finally, the global optimal design is predicted and the optimally designed one is manufactured, and the numerical results and measured results are reported to validate the effectiveness of this proposed method.

In this paper, the maximum thrust force per ampere (MTPA) strategy for saturated permanent magnet linear synchronous motors over the entire field weakening region is presented. In other words, influence of magnetic saturation on the MTPA and field weakening strategies as well as motor-inverter limitations is considered. Using the modified MTPA strategy leads to minimized copper losses, and so maximum capacity of motor is utilized. The proposed scheme incorporates all optimal strategies and operates the drive within the voltage and current limits of the motor/inverter. Simulation results for a prototype interior permanent magnet linear synchronous motor demonstrate that the MTPA and field weakening strategies can be successfully implemented for vector controlled saturated permanent magnet linear synchronous motor drives.

In recent years, a permanent magnet linear synchronous motor (PMLSM) has been used in various kinds of transportation applications for its relative high power density and efficiency. The general transportation system arranges the armature on the full length of transportation lines. However, when this method is applied to long distance transportation system, it causes increase of material cost and manufacturing time. Thus, in order to resolve this problem, we suggested stationary discontinuous armature PMLSM. However, the stationary discontinuous armature PMLSM contains the edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem because the cogging force that they exert bad influences the controllability of the motor. Therefore, in this paper we proposed the combination of skewed magnets and stair shape auxiliary teeth to reduce the force by edge effect. Moreover, we analyzed the influence of the design factors by using a 3-D finite element method (FEM) simulation tool.

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.