Permanent Magnet Type Research Articles

A General Analytical Model of Permanent Magnet Eddy Current Couplings

An improved practical two-dimensional model for the analytical calculation of the magnetic field distributions in permanent magnet (PM) eddy current couplings is presented to obtain the torque characteristics. By establishing the Cartesian coordinate reference system on the rotating conductor, the PM region is treated as a source of traveling wave magnetic field and then the multi-layer boundary value problem is solved. The formulation for the magnet blocks, the eddy current and saturation effects in the solid secondary back iron, and the equivalence relationships between typical PM shapes, are all reasonably taken into account. Calculation results produced by the proposed analytical model are compared with those from the nonlinear finite element method and experimental measurement.

Performance Evaluation and Comparison of Switched Reluctance Cylindrical Linear Motor

Nowadays, most of the researchers have put a lot of effort in designing the permanent magnet type of linear motor. However, due to resource problem occur recently to the permanent magnet material has led to increment of the material cost. This situation made the linear motor development cost is increase as well. Because of this reason, most of linear motor manufacturers are prefer to development non-permanent magnet type to ensure stability and competitive price. Therefore, in this research, a switched reluctance linear motor was designed. The teeth shape has been varied in order to observed the effect to it’s performance. As a result, the best model of switched reluctance linear motor with optimum teeth shape has been proposed. The performance of the model also has been compared to other similar type of linear motor and the permanent magnet type of linear motor.

Simulation and Experimental Study of Oscillator for Permanent Magnet Vibration-to-Electrical Power Generator

This paper presents the simulation and testing of Vibration-to-Electrical Power Generators (VEPG) with different kinds of permanent magnet oscillators for scavenging ambient vibrations. The finite element method is used for magnetic fields calculation. Firstly, single permanent magnet type oscillators are simulated under the sinusoidal vibration. The calculation results show that the permanent magnet oscillator with diameter 20 mm and height 5 mm will realize 4 V peak-peak voltage. Secondly, multiple permanent magnets type oscillators are simulated under the same vibration and comparative studied with the single permanent magnet type. The results show that multiple permanent magnets oscillator with suitable structure will dramatically improve the power density of VEPG. By the end, prototypes with different kinds of oscillators are tested on the condition of sinusoidal vibration. And the experimental results agree well with the simulation ones.

Permanent magnet electron beam ion source/trap systems with bakeable magnets for improved operation conditions

The magnetic system of a Dresden electron beam ion source (EBIS) generating the necessary magnetic field with a new type of permanent magnet made of high energy density NdFeB-type material operable at temperatures above 100 °C has been investigated and tested. The employment of such kind of magnets provides simplified operation without the time-consuming installation and de-installation procedures of the magnets for the necessary baking of the ion source after commissioning and maintenance work. Furthermore, with the use of a new magnetization technique the geometrical filling factor of the magnetic Dresden EBIS design could be increased to a filling factor of 100% leading to an axial magnetic field strength of approximately 0.5 T exceeding the old design by 20%. Simulations using the finite element method software Field Precision and their results compared with measurements are presented as well. It could be shown that several baking cycles at temperatures higher than 100 °C did not change the magnetic properties of the setup.

Application of Svpwm in New Type Permanent Magnet Synchronous Motor Based on Agv

Application of Svpwm in New Type Permanent Magnet Synchronous Motor Based on Agv

Quantitative Comparison of Linear Magnetic Gear with Different Types of PMs

This paper presents a quantitative comparison between the non-rare-earth permanent magnet (PM) and rare-earth PM based linear magnetic gear. By using the finite element analysis, three linear magnetic gears adopting either the non-rare-earth PM or rare-earth PM are analyzed and discussed. Hence, the cost-effectiveness comparison among different types of PMs is conducted. The results indicate that the non-rare-earth PM is preferred to the rare-earth PM for application to linear magnetic gears when cost-effectiveness is emphasized.

수동변속기용 비접촉식 변속단 감지센서 개발

The present paper relates to a development of the Gear Detection Sensor for automotive manual transmission. To detect air gap from control finger to detecting zone of sensor based on non-contacted method, permanent magnet and linear type Hall IC are mounted in this sensor. Control finger is machined to 3 step heights to detect 3 gear stages such as In-Gear, Normal and Rear. After conducting actual experimentation based on exclusive Jig and FEM, it is described to consider possibility for automotive application of Gear Detection Sensor.

Modeling and Design Optimization of Contactless Sliding Transformer System for Ropeless Elevators

In this paper, two novel topological structures of sliding transformer with ferromagnetic core applied in the Contactless Electrical Power Transmission (CEPT) system used for the ropeless elevator driven by moving-coil type Permanent Magnet Synchronous Linear Motor (PMLSM) have been proposed, and the magnetic field distribution is calculated and analyzed by the finite element method (FEM). According to the analysis results of the traditional E-E topology sliding transformer, much higher coupling coefficients of sliding transformers with proposed topologies have been obtained. Then, based on the magnetic distribution and the circuit model of system, the compensation capacitances have been calculated considering supply frequency and load conditions. Finally, the load characteristic of the system with compensation is also obtained by FEM.

Design and simulation of disk stepper motor with permanent magnets

Abstract In this paper the design and the magneto-static simulation of axial-flux permanent- magnet stepper motor with the disc type rotor is presented. Disk motors are particularly suitable for electrical vehicles, robots, valve control, pumps, centrifuges, fans, machine tools and manufacturing. The brushless machine with axial flux and permanent magnets, also called the disc-type machine, is an interesting alternative to its cylindrical radial flux counterpart due to the disk shape, compact construction and high torque density. This paper describes a design of four phase microstepping motor with the disc type rotor. The FEM modeling and the 3D magneto-static simulation of the disk stepper motor with permanent magnets is being subject of the article, too. Disc rotor type permanent magnet stepper motor for high torque to inertia ratio is ideal for robotics and CNC machines.

Permanent Magnet Flux-Switching Machine, Optimal Design and Performance Analysis

In this paper an analytical sizing-design procedure for a typical permanent magnet flux-switching machine (PMFSM) with 12 stator and respectively 10 rotor poles is presented. An optimal design, based on Hooke-Jeeves method with the objective functions of maximum torque density, is performed. The results were validated via two dimensions finite element analysis (2D-FEA) applied on the optimized structure. The influence of the permanent magnet (PM) dimensions and type, respectively of the rotor poles' shape on the machine performance were also studied via 2D-FEA.

Simulations Analysis with Comparative Study of a PMSG Performances for Small WT Application by FEM

Permanent magnet synchronous generators (PMSGs) have a bright prospect in the small wind turbine (WT) applications; PMSGs co mpared to the conventional electrically excitated generators have many advantages, that's why they have attracted many and a strong interest of research. In this paper, a co mparative PMSG performance study's is presented, these performances is studied as a function of physical material like the type of permanent magnet (high, poor, average and linear), as a function of the environ mental conditions as rotor speed, finally, as a function of the design and geometrical parameters (rotor length, number of poles, nu mber of stator slots). These results are obtained by finite element method (FEM ); this approach is a powerful and useful tool to study and design PMSGs, as represented in this paper.

Comparison of Synchronous Motors With Different Permanent Magnet and Winding Types

This paper deals with the design of permanent magnet synchronous motors (PMSMs) with ferrite magnets and their comparison with synchronous machines with NdFeB magnets. In recent years, ferrite magnets have become popular due to their rather low cost and, what is more important, due to increasing of the NdFeB magnets cost last time. The progress in ferrite magnet material properties during the latest decade gave rise to their use in high power applications. Their remanent flux density today reaches values beyond 0.4 T, which allows design electrical machines with acceptable performance. In this paper, three designs of ferrite machines are presented and compared with a real PMSM with NdFeB magnets. Furthermore, the influence of the stator winding type and the shape of the slot opening on the PMSM properties will be demonstrated. All machines are designed for the same output power as the original PMSM with NdFeB magnets. This paper demonstrates that ferrite magnets can, to some extent, be used as replacements for the NdFeB magnets in high-efficiency power applications.

Preparation of the Velocity Ripple Suppression for Intermittent Stator Permanent Magnet Linear Synchronous Motor

Recently, the permanent magnet type linear synchronous motor (PM-LSM) is used as a driving source in transportation systems. In order to apply to the source of the power of the long-distance conveyance equipment, our laboratory have proposed an intermittent stator PM-LSM (ISPM-LSM). However, ISPM-LSM produces the velocity ripple due to an outlet edge of the stator. The sequence of the section changing method is changed in this paper. This suppresses the velocity ripple. The verification is performed using both of the simulation and experimental device.

Dipolar openable Halbach magnet design for High-Gradient Magnetic Filtration

High-Gradient Magnetic Filtration (HGMF) uses heavy electromagnets or c-shaped type permanent magnets in order to generate a magnetic field. When using electromagnets, permanent operation only is possible if an effective cooling system (e.g. water, air) is applied. The operation costs are high due to the electric power consumption. In order to reduce operation costs the use of permanent magnets thus is very advantageous. Most permanent magnet systems that are currently used for HGMF are of the c-shaped type equipped with pole caps and iron yoke which makes them big and heavy. In terms of magnet weight versus magnetic flux density, Halbach type permanent magnets are much more efficient. The present work deals with a dipolar Halbach magnet, called Mandhala (Magnetic Arrangement for Novel Discrete Halbach Layout) which consists of rings from identical magnet blocks that are stacked on top of each other and can be split at optimal angles. We developed a formula which allows to calculate the magnetic flux density along the bore axis for a series of equidistant stacked rings. An optimization program using the genetic algorithm (ga) of MATLAB supports the design and up-scale of the Halbach magnet for HGMF applications as it minimizes the magnet material amount for the user fixed minimum constraints of magnetic flux density and open area for filter introduction. The Halbach magnet that was constructed in this study generates a flux density of 0.37T in the center and offers a region of 160mm within the length of the bore axis in which the magnetic flux density does not fall below 0.29T. This field is sufficiently strong to separate submicron magnetic particles with high efficiency. The built Halbach magnet is more cost-effective, more compact and lighter than c-shaped permanent magnets.

Design of a DC-AC Link Converter for 500W Residential Wind Generator

As one of alternative sources of renewable energy, wind energy has an excellence prospect in Indonesia, particularly in coastal and hilly areas which have potential wind to generate electricity for residential uses. There is urgent need to locally develop low cost inverter of wind generator system for residential use. Recent developments in power electronic converters and embedded computing allow improvement of power electronic converter devices that enable integration of microcontrollers in its design. In this project, an inverter circuit with suitable control scheme design was developed. The circuit was to be used with a selected topology of Wind Energy Conversion System (WECS) to convert electricity generated by a 500W direct-drive permanent magnet type wind generator which is typical for residential use. From single phase AC output of the generator, a rectifier circuit is designed to convert AC to DC voltage. Then a DC-DC boost converter is used to step up the voltage to a nominal DC voltage suitable for domestic use. The proposed inverter then will convert the DC voltage to sinusoidal AC. The duty cycle of sinusoidal Pulse-Width Modulated (SPWM) signal controlling switches in the inverter was generated by a microcontroller. The lab-scale experimental rig involves simulation of wind generator by running a geared DC motor coupled with 500W wind generator where the prototype circuit was connected at the generator output. The experimental circuit produced single phase 240V sinusoidal AC voltage with frequency of 50Hz. Measured total harmonics distortion (THD) of the voltage across load was 4.0% which is within the limit of 5% as recommended by IEEE Standard 519-1992.

Optimum Design of Interior Permanent Magnet Motor for Automotive Cooling Device

In this paper, we developed stator and rotor shapes of interior permanent magnet type brushless motor for automotive cooling device in order to obtain better performance than the prototype. Response surface methodology (RSM) is employed in this paper as an optimization method. Finite element computations have been used for numerical experiments on geometrical design variables in order to determine the coefficients of a second order model for the RSM. The optimum design results confirm that desirable improvements in cogging torque, back-EMF and THD are achieved.

Stator and Rotor Shape Designs of Interior Permanent Magnet Type Brushless DC Motor for Reducing Torque Fluctuation

This paper presents the stator and rotor shape designs in interior permanent magnet (IPM) type brushless dc (BLDC) motor for reducing torque fluctuation. The partly enlarged air-gap made by rotor unequal out diameter and stator core structure with pole shoe modification is introduced. The torque ripple reduction is achieved by upgrading torque value at minimum torque position and their detail characteristics are compared. The final stator and rotor shape of IPM type BLDC motor is decided by design of experiments (DOE) process. The magnetic field and torque characteristics are analyzed by 2 dimensional (2D) finite element analysis (FEA) and their performances are validated by experimental results.

A Ferrite PM In-Wheel Motor Without Rare Earth Materials for Electric City Commuters

Electric city commuters are vehicles used for commuting from suburbs to inner cities and for movement within cities. Because of the short distances that they cover and their small battery size, such vehicles are beginning to attract attention. Generally, a high-performance permanent magnet (PM) composed of rare earth elements, such as neodymium and dysprosium, is used in the in-wheel PM synchronous motor (PMSM) of an electric city commuter. However, rising prices of rare earth elements and export restrictions on them are serious problems. Development of an in-wheel PMSM that does not utilize rare earth PMs is therefore highly desirable for electric city commuter vehicles. Accordingly, our research group has focused on a surface PM type axial gap structure that can achieve a high torque density and a short motor length in the axial direction. The designed motor structure with ferrite PMs replacing the rare earth PMs and the results of a 3-D finite element analysis are introduced in detail in this paper. Moreover, to examine the fundamental characteristics of the designed motor, a prototype is produced and tested.

Optimal design of permanent magnet linear synchronous motor for ultra low force pulsations

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as pole-arc to pole-pitch ratio of magnet, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combined computation of two dimensional (2-D) finite element method (FEM) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEM calculated results of the detect forces for different combinations of factors. With the help of the combined computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.

Vibration Transmission Analysis on a Superconducting Seismic Isolation Device With PM and Copper Plate Systems

We have devised a magnetic levitation type superconducting seismic isolation device using pinning effect of HTS bulk and investigated the characteristics of vibration transmission and damping in a model device with two types of permanent magnet (PM) systems with copper plates; the one was for stable stationary levitation named “PM-PM system” and the other was for improving damping effect named “vibration absorbing system (VAS)”. To clarify the electromagnetic behaviors of these systems, we calculated the distributions of eddy current and magnetic force within the copper plates during a horizontal vibration using a numerical simulation code based on the three-dimensional finite element method (3D-FEM) analysis. As the results, the vibration transmission was reduced due to the Lorenz force generated in the copper plate.