Marek Przybylski

Brushless DC motor with a bonded permanent magnet and powder magnetic core

Powder magnetic circuits find more and more application in modern electric machines. These magnetic circuits frequently comprise soft magnetic core and powder permanent magnets as a source of magnetic flux of excitation. It is connected with a lot of advantages of these kinds of materials. The main purpose of the work is to design a brushless DC motor with powder permanent magnet and powder soft magnetic core. It was assumed that the powder magnetic core will be prepared from iron powder bonded by resin and permanent magnet will be prepared from powder of Nd-Fe-B melt-spun ribbon. Investigation of technology of magnetic materials was done and presented. Measurements of properties of magnetic materials were considered in design and analysis of motor. During designing process the dimensions and operational parameters of designing motor were assumed. Permanent magnet DC brushless motor with nominal power 250 W and rotational speed 6000 rpm was designed.

The application of powder magnetic circuits in electric machines

Development of new magnetic materials enables development of electric machines. Nowadays a lot of universities, research centers and factories work on application of powder magnetic circuits in electromagnetic transducers. This type of magnetic circuits has a lot of advantages. The paper presents methods of tailoring physical properties of powder magnetic circuits and the influence of the type of magnetic circuits on the parameters of electric motors.

New PM magnetic developments

Operating parameters of electric machines depend, among other things, on the parameters of magnetic circuit used in the machine…

The influence of cryogenic temperatures on the characteristics of a brushless motor

this article presents the results of a study on the magnetic properties of soft magnetic powder composites at room temperature and at liquid nitrogen temperature. the properties of a magnetoelectric motor with the power of 0.75 kw at room temperature and cryogenic temperatures are also presented in this article. the study of magnetic properties showed that magnetization curves at 20°c and -195.8°c temperatures are almost the same. iron loss in the composite at liquid nitrogen temperature increased significantly in comparison to loss at room temperature. the study of the magnetoelectric motor showed that the back electromotive force at liquid nitrogen temperature decreases insignificantly in comparison to the back electromotive force at room temperature. electromagnetic torque at liquid nitrogen temperature increases in comparison to room temperature.

Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated.

Field-Based Analysis and Optimal Shape Synthesis of Switched Reluctance Motors

This study focuses on a class of a three-phase switched reluctance motor. The aim of the paper is to optimize torque and iron loss as a function of the geometry. To enhance the efficiency of the motor, a procedure of automated optimal design is adopted. The analysis model of the motor is based on 2D finite element method simulation, while the design optimization is based on evolutionary computing.

Magnetic Composites in Electric Motors

Magnetic composites are manufactured as magnetic powder bonded by dielectric material, which bond and insulate powder grains. Magnetic composites are applied in electric machines due to their favorable magnetic and mechanical properties as well as possibility of tailoring their physical properties. The paper is a review of soft and hard magnetic composites, their internal structure, properties, and advantages resulted from their application on magnetic circuits of electric motors.

Wind-driven optimization for the design of switched reluctance motors

In the paper, the Wind Driven Optimization WDO algorithm is applied to the optimal shape design of a class of switched reluctance motors. The goal of the optimization is to identify a class of geometries which maximize the torque and simultaneously minimize the iron losses of the motor. Because of the twofold design criterion, the multi-objective version of the wind driven algorithm M-WDO is used. Results are eventually compared with those obtained by means of a standard genetic algorithm GA.

Numerical analyses of a radial flux motor with a double-sided rotor, Nd-Fe-B magnets and the soft magnetic composite stator: Part 1

The paper deals with numerical analyses of a radial flux motor with double-sided rotor. The motor was designed with Nd-Fe-B sintered magnets and soft magnetic stator made of iron powder. The motor was designed for assessment of possibility of construction high torque motors with the powder stator for e.g. electric vehicles or washing machines. The motor is assumed to have stator composed from segmented parts made of iron powder. Those parts are assumed to be made by pressing the powder in a die or cut from larger parts by electric discharge machining. The motor stator was designed with uses of special construction powder components and is subjected of a Polish patent application. Designed stator should have better mechanical performance than stator made of electrical steel.

Design of linear motor with two degrees of freedom

This paper presents a construction of the flat stepper motor with a complex move of soft magnetic plate with one multipolar permanent magnet. Stator has 16 cylindrical electromagnets which are combined in 4 phases. This solution is advantageous because it simplifies the way of controlling motor. In this case there are only 8 wires and the external driver controls currents in only 4 phases. Unlike in the solutions where many glued permanent magnets are used, it was considered a possibility to produce one permanent magnet which will be multipolarly magnetized. A special magnetization fixture allows hard magnetic material to be magnetized in the required distribution of poles. Flat stepper motor with multipole permanent magnet can lead to further considerations on the construction of linear rotary motor.