Feng Xing

Characteristic analysis of an ironless linear synchronous motor with novel halbach magnet array

A novel ironless synchronous permanent magnet linear motor with Halbach array is proposed. The operation principle and structure of this linear motor are introduced. Based on magnetic vector potential equation and boundary conditions, flux density distribution induced by the permanent magnet array is analysed analytically. And then the expression of the air-gap flux density distribution was derived. Characteristics such as thrust and back-EMF are obtained analytically and compared with the finite element simulation results. A prototype machine is manufactured and some experimental study is carried out, which validate the analytical and simulated results.

Modeling and analysis of a magnetically levitated synchronous permanent magnet planar motor with concentric structure winding

This paper propose a novel magnetically levitated synchronous permanent magnet planar motor with concentric structure windings. The analytical model of the novel magnetically levitated synchronous permanent magnet planar motor is established, flux density distribution of the two-dimensional Halbach magnet array is obtained by solving the equations of the scalar magnetic potential. Simulation results obtained by finite element method (FEM) is used to validate the analytical ones. A prototype motor is manufactured in laboratories and some experiments are carried out with the prototype.

Levitation force control of maglev permanent synchronous planar motor based on multivariable feedback linearization method

The whole control system is a strong coupling, nonlinear and multivariable system because the motion of maglev permanent magnet synchronous planar motor has multi-degrees of freedom and the magnetic field produced by the permanent magnet decreases nonlinearly in the vertical direction. The decoupling and linearization of the levitation force is the key part for high-speed and high-precision control. The paper analyzes the mathematical model and the levitation force of the motor. After that, the paper designs a nonlinear controller, which achieves the goal of decoupling and linearizing the multivariable and nonlinear system, by using multivariable feedback linearization method. The simulation result in Matlab/Simulink shows that the whole control system has high-speed response to the given reference and good robustness under disturbance.

Synchronous control of dual linear motors based on advanced space voltage vector switch table

One advanced control method based on a new kind of space voltage vector switch table is proposed in this paper to synchronize dual permanent magnet linear motors (PMLSM). With the aid of this method, synchronous control is realized by one control system with dual linear motors, rather than using two individual control systems to control each linear motor separately. In the system of dual motor synchronous control, when one of the two linear motors experiences load disturbance or receives speed feed instruction from the controller, there will be synchronous position deviation between the two linear motors, which should be reduced. Advanced space voltage vector switch table can be redesigned based on the synchronization position deviation, estimated stator flux linkage, estimated electromagnetic thrust, and which section the stator flux linkage is located in. The dual linear motors can be controlled to work synchronously by selecting the appropriate space voltage vector. The synchronous position deviation between the two motors is used to determine the space voltage vector in the next control cycle, in which way the synchronous control of the two linear motors can be realized rationally and efficiently in one control system. The experiment result shows that synchronous precision and response speed between the two linear motors can be improved greatly by this control method.

Force characteristic analysis of a magnetic gravity compensator with annular magnet array for magnetic levitation positioning system

Magnetic levitation positioning system (MLPS) is considered to be the state of the art in inspection and manufacturing systems in vacuum. In this paper, a magnetic gravity compensator with annular magnet array (AMA-MGC) for MLPS is proposed. Benefiting from the double-layer annular Halbach magnet array on the stator, the proposed AMA-MGC possesses the advantages of symmetrical force, high force density and small force fluctuation. Firstly, the basic structure and operation principle of the AMA-MGC are introduced. Secondly, the basic characteristics of the AMA-MGC such as magnetic field distribution, levitation force, parasitic force and parasitic torque are analyzed by the three-dimensional finite element analysis (3-D FEA). Thirdly, the influence of structural parameters on force density and force fluctuation is investigated, which is conductive to the design and optimization of the AMA-MGC. Finally, a prototype of the AMA-MGC is constructed, and the experiment shows good agreement with the 3-D FEA results.Magnetic levitation positioning system (MLPS) is considered to be the state of the art in inspection and manufacturing systems in vacuum. In this paper, a magnetic gravity compensator with annular magnet array (AMA-MGC) for MLPS is proposed. Benefiting from the double-layer annular Halbach magnet array on the stator, the proposed AMA-MGC possesses the advantages of symmetrical force, high force density and small force fluctuation. Firstly, the basic structure and operation principle of the AMA-MGC are introduced. Secondly, the basic characteristics of the AMA-MGC such as magnetic field distribution, levitation force, parasitic force and parasitic torque are analyzed by the three-dimensional finite element analysis (3-D FEA). Thirdly, the influence of structural parameters on force density and force fluctuation is investigated, which is conductive to the design and optimization of the AMA-MGC. Finally, a prototype of the AMA-MGC is constructed, and the experiment shows good agreement with the 3-D FEA results.

An accurate real-time model of maglev planar motor based on compound Simpson numerical integration

To realize the high-speed and precise control of the maglev planar motor, a more accurate real-time electromagnetic model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic model. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed model has high accuracy and can realize practical application easily.To realize the high-speed and precise control of the maglev planar motor, a more accurate real-time electromagnetic model, which considers the influence of the coil corners, is proposed in this paper. Three coordinate systems for the stator, mover and corner coil are established. The coil is divided into two segments, the straight coil segment and the corner coil segment, in order to obtain a complete electromagnetic model. When only take the first harmonic of the flux density distribution of a Halbach magnet array into account, the integration method can be carried out towards the two segments according to Lorenz force law. The force and torque analysis formula of the straight coil segment can be derived directly from Newton-Leibniz formula, however, this is not applicable to the corner coil segment. Therefore, Compound Simpson numerical integration method is proposed in this paper to solve the corner segment. With the validation of simulation and experiment, the proposed model has high accuracy and can ...

Electromagnetic and Mechanical Characteristics Analysis of a Flat-Type Vertical-Gap Passive Magnetic Levitation Vibration Isolator

In this paper, we describe a flat-type vertical-gap passive magnetic levitation vibration isolator (FVPMLVI) for active vibration isolation system (AVIS). A dual-stator scheme and a special stator magnet array are adopted in the proposed FVPMLVI, which has the effect of decreasing its natural frequency, and this enhances the vibration isolation capability of the FVPMLVI. The structure, operating principle, analytical model, and electromagnetic and mechanical characteristics of the FVPMLVI are investigated. The relationship between the force characteristics (levitation force, horizontal force, force ripple, and force density) and major structural parameters (width and thickness of stator and mover magnets) is analyzed by finite element method. The experiment result is in good agreement with the theoretical analysis.

Research on a novel synchronous permanent magnet planar motor with concentric winding for lithography

A novel synchronous permanent magnet planar motor (SPMPM) which with concentric structure winding is investigated in this paper. Topology of this SPMPM is introduced, and as the mover can move freely on the stator, the planar motor is suitable for long-stroke applications in the lithography. Flux density, electromagnetic thrust and back-EMF of the SPMPM are obtained analytically and compared with the finite element simulation results. A prototype is manufactured and tested successfully. The measured values matching the simulated ones well.

A magnetically levitated synchronous permanent magnet planar motor with concentric structure winding used for lithography machine

A novel magnetically levitated synchronous permanent magnet planar motor (MLSPMPM) with concentric structure winding, which can be used in lithography machine, is proposed in this paper. Topology and principle of the new MLSPMPM are introduced. The scalar magnetic potential is used to solve the magnetic system, and the differential equations are solved by the separation of variables method according to the boundary conditions. Characteristics, such as flux density, electromagnetic force, and back-EMF of the MLSPMPM, are obtained analytically. All of the results are validated by the finite element method. A prototype of the MLSPMPM is manufactured. Based on the prototype motor, some experiments are carried out. The measured results are used to showcase the validity of the analytical analysis.

Control strategy for nine phase maglev permanent magnet synchronous planar motors driven by composite current

The paper present a control strategy for nine phase maglev permanent magnet synchronous planar motors driven by composite current. Maglev planar motor driven by composite current can increase the utilization of the winding and reduce the mass of the mover of the maglev planar motor with moving coil type structure. As a result, the dynamic performance of the motor can be increased. The basic structure and operational principle of the composite current driven maglev planar motor are introduced in the paper. The mathematical model based on its special structure and the d-q coordinate transformation due to the composite current driving are also presented in the paper. Current distribution matrix is used to decouple the 6 degrees of freedom of the motor. The simulation result proves that it has both high stability and high-speed dynamic performance.