Search

The permanent magnet linear synchronous motors have the advantages of high efficiency, high thrust density and high power factor, which is mostly attractive to the fields of electromagnetic launch. The electromagnetic field of long primary PMLSM with different structures are analyzed firstly by finite element method in this paper. Then, the thrust characteristics of the motors with different topologies are studied and compared, which fully demonstrates the advantages and feasibility of the proposed PMLSM.

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 direct thrust force control scheme of permanent magnet synchronous linear motor is mainly inspired by the direct torque control of its rotating counterparts so as to achieving excellent force characteristics. However, due to the inherent characteristics of permanent magnet linear synchronous motor, such as open-wide air gap, small equivalent inductance and large mechanical time constant, the control performance of traditional direct thrust control algorithm is greatly deteriorated, which are of prime concern. In this paper, the traditional direct thrust control of permanent magnet linear synchronous motor is analyzed strictly, with the limitations pointed out. Contributed to the concept of predictive control, by optimizing of switching vector and introduction of disturbance observer, the thrust performance of direct thrust force control is improved. At the same time, switching frequency can be optimized, thrust and flux ripple can be suppressed, and outer loop control performance can be improved, when compared to the state of the art.

A design scheme of a new high-speed high-power permanent magnet linear synchronous motor for the driving source of impact acceleration simulation device is proposed. The electromagnetic properties of no-load back EMF, cogging force, air gap flux density and electromagnetic thrust are calculated by finite element method. The maximum theoretical thrust of the linear motor is obtained. Besides, the characteristic curves of electromagnetic thrust and initial phase angle of current are obtained. The structure of permanent magnet linear synchronous motor is optimized and analyzed. The motor thrusts under different structure scheme are also compared, and a good design scheme of high speed and high power permanent magnet linear synchronous motor is proposed. The research in this paper is of great reference significance to the further research on this type of motor.

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.