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This paper deals with a design of the exciter which is a self-magnetizing apparatus of a written-pole motor (WPM). For a given rotor of 0.2 hp WPM, the pole shape and winding specifications of the exciter which is driven by a general voltage are optimally designed. Then, with consideration of hysteresis characteristics of a magnetic layer, the magnetization waveform is investigated with Preisach model. To validate the results calculated in design and analysis, the experimental test is carried out and comprehensive test results are suggested. Index Terms--Exciter, hysteresis, magnetization, Preisach, written pole motor.

In this paper, we investigate the effects of space harmonics of single-phase fine start permanent-magnet (LSPM) motors on starting performance. We construct an equivalent electric circuit considering the harmonics for the analysis, in which the magnetostatic field computation is coupled with finite-element modeling. We analyze the starting characteristics by circuit simulation and show that the results compare well with those of time-step finite-element analysis and of experiments. Index Terms--Equivalent circuit, line-start permanent magnet motor, space harmonics, starting torque.

This paper proposes a newly structured double excited two-degree-of-freedom (DOF) motor with tilt/pan motion to use in a security camera. For applications in active vision, a tilt/pan mechanism should be accurate, fast, small, inexpensive, and have low power requirements. We have designed a new type of motor meeting these requirements, which incorporates both tilt and pan into a single, two-degree-of-freedom device. The focus of the research is to design the improved 2-DOF motor which can eliminate the drawbacks as manufacturing, complicated control, and difficulty in lamination in conventional model. Additionally, to effectively improve the torque characteristic, the main pole pitch and the auxiliary pole shape are determined by the pan motion and the tilt motion, respectively. The validity of proposed structure will be shown in the computer simulation of the newly structured double excited 2-DOF motor for security cameras. Index Terms--Multi-degree-of-freedom (DOF), security camera, spherical motor, tilt/pan, 3-D finite-element method.

This paper describes a new position sensorless starting method, specialized for low-cost applications, of a brushless dc (BLDC) motor with a surface permanent-magnet (SPM) rotor to prevent demagnetization of permanent magnet and vibrations due to pulsating currents during the starting period. That the magnitude of peak current causes irreversible demagnetization of permanent magnet, has been measured through experimental tests. The proposed method limits the motor currents during the starting period to lower than the demagnetization currents by doing commutation depending on the level of the measured phase currents. Experimental results show that the proposed method implemented in an inverter for a BLDC motor-driven reciprocating compressor considerably reduces not only the pulsating currents but also the vibration of the compressor during starting. Index Terms--Brushless dc motor, reciprocating compressor, sensorless control, starting method.

This paper proposes a rotary magnetic position sensor (RMPS) which has a sinusoidally magnetized permanent magnet (PM) with a small number of poles. To make the sinnsoidal magnetic flux density distribution from the PM, a magnetizing fixture is designed by adjusting its pole shape. The magnetization process is analyzed using the Preisach model and two-dimensional finite-element method (FEM). The simulation result of the magnetization is compared with the experimental one. Also, the ability of position detection from two sinusoidal signals is shown. Index Terms--Finite-element method, magnetization, Preisach model, rotary magnetic position sensor.

This paper proposes a novel rotor pole shape which consists of a uniform surface and an eccentric surface to make a sinusoidal magnetic flux density in air gap in order to reduce cogging torque, torque ripple, and harmonics of back-electromotive force waveform in spoke-type brushless DC motor. In the process of design and analysis, response surface methodology and the 2-D finite-element method are employed to obtain the rotor geometry and verify the results of the novel rotor pole shape. Index Terms--Brushless DC (BLDC) motor, cogging torque, finite-element method, response surface method, torque ripple.

This paper presents a novel method to reduce commutation torque ripple in a position sensorless brushless dc (BLDC) motor drive. To compensate the commutation torque ripple considerably, conventional methods should know commutation interval, so that they need current sensors. However, the proposed method measures commutation interval from the terminal voltage of a BLDC motor, calculates a pulsewidth modulation (PWM) duty ratio using the measured commutation interval to suppress the commutation torque ripple, and applies to the calculated PWM duty ratio only during the next commutation. Experimental results verify that the proposed method implemented in an air conditioner compressor controller considerably reduces not only the pulsating currents but also vibrations of a position-sensorless BLDC motor. Index Terms--Brushless dc (BLDC) motor, commutation torque ripple, sensorless drive.

This paper propose the newly structured micro permanent magnet (PM) type stepping motor with claw-poles. The micro PM type stepping motor is the preferred solution for many small electronics position determination devices since it could be miniaturized. Thus, there are growing demands for PM type stepping motors with a greater mechanical torque and a smaller size. In this paper, a newly structured micro PM type stepping motor of a 6.0-mm-outer diameter is proposed. Magnetic characteristic of the developed model in comparison with the general type model is analyzed using the three-dimensional finite element analysis (3-D FEA). Simulation and experiment are performed to verify the advantages of the developed motor. Index Terms--Claw-pole, finite element analysis (FEA), holding torque, miniaturization, PM type stepping motor.

This paper proposes optimal design method of stator slot for three-phase cage induction motor fed by six-step inverter output voltage by using proposed analysis method. The finite-element method (FEM) on one phase band stator periodic condition is coupled with harmonic equivalent circuit. Using the FEM, the stator slot is optimally designed and the result is presented. Stator core loss and copper loss including harmonic loss are reduced by the proposed optimum slot design method. The analysis result is verified by experimental measurement. Index Terms--Core loss, harmonic loss, inverter-fed induction motor, optimal design, stator slot.

In this paper, we propose a design procedure and methods for designing the post-assembly magnetization system of a three-phase line start permanent-magnet motor (LSPM). According to the design procedure and the design methods, the post-assembly magnetization system is designed and manufactured. From the experimental results, we verify that the permanent magnet of LSPM is successfully magnetized. Index Terms--Design method, design procedure, line start permanent magnet (LSPM), post-assembly magnetization system.

This paper presents the shape design of the permanent magnet for a rotary type magnetic position sensor for an automobile acceleration pedal using a new two-dimensional (2-D) analysis method. Basically, its flux path is not uniform in the axial direction because the magnetic flux flows three-dimensionally (3-D) between the stator yoke and permanent magnet. So, the analysis and design of the magnetic position sensor has to consider the 3-D shape. We propose a 2-D analytical modeling method of magnetic position sensor account for fringing effects and optimize the shape of the permanent magnet for a high linearity characteristic. Then, the validity of the developed method is confirmed by comparing the calculated values with the measured values. Index Terms--Finite element analysis (FEA), fringing effect, fringing permeance, magnetic position sensor.

This paper presents the operating characteristic analysis of a permanent magnet (PM)-type magnetic circuit breaker using the two-dimensional finite-element magnetic field solution, taking into account nonlinearity of the material and the eddy current. The effect of the eddy current on the dynamic characteristic of the breaker is analyzed from the finite-element analysis. A new modified model to decrease the eddy current is proposed. The characteristics of the two models are compared. Index Terms--Eddy current, finite-element analysis, nonlinearity, permanent magnet (PM)-type magnetic circuit breaker.

A major problem of switched reluctance motors (SRMs) is torque ripple, which causes undesirable acoustic noise and vibration. It is caused by the saliency of the stator and rotor. In this paper, the geometry for low torque ripple is researched and a motor having notched teeth is proposed. Its characteristics are simulated by finite-element method (FEM) analysis and compared with SRMs having conventional shape. Index Terms--Rotor tooth shape, switched reluctance motor, torque ripple.

This paper describes the effect of eddy currents generated in the rotor steel shell of exterior - rotor type permanent magnet brushless DC motor of which the rotor is revolving at a high speed. A two dimensional time-stepped finite element method is used to analyze an electromagnetic field and compute motor performance. The conductivity of the rotor steel shell is modified to consider the transverse edge effect. As a result, the effect of eddy currents is shown by comparing the analysis results between when the proposed method is used and when the method is not used. Index Terms - Brushless DC motor, eddy currents. finite element methods, permanent magnets.

This paper describes the finite element analysis of a direct thrust-controlled linear induction motor(LIM). The time-stepping finite element method and the moving mesh technique are used to calculate the dynamic characteristics of LIM during the direct thrust control. Because LIM has the end effect, thrust correction coefficient is introduced to predict an actual thrust in control. The simulation results, the thrust and the stator flux linkage are shown below and the stator current is compared with an experimental one. Index Terms - Direct thrust control, linear induction motor, thrust correction coefficient, finite element methods.

This paper presents a fast and accurate d-q axis equivalent circuit model of linear induction motor (LIM) for drive system simulations. The developed model was built based on nonlinear transient finite element analysis to obtain the asymmetric d-q equivalent constants for static end effect and the distorted air gap distribution by velocity for dynamic end effect. The model was implemented in a vector control environment through the creation of a d-axis magnetizing inductance to account for the reduction of the magnetizing inductance due to eddy current. Since the d-q axis equivalent circuit model of LIM considering both end effects has not been exactly completed, the significance of the work is that it provides an accurate d-q axis equivalent circuit model of LIM for utilization in simulation environments. Index Terms--Dynamic end effect, finite element analysis (FEA), linear induction motor (LIM), static end effect.

The winding of slotless BLDC (SLBLDC) motor has a rhombic shape or hexagonal shape in its axial direction. So, its shape is not uniform in its axial direction. The analysis and design of slotless brushless dc (SLBLDC) motor must consider the three-dimensional (3-D) shape of the winding. In particular the magnetization distribution of PM as well as the shape determines the output characteristics of SLBLDC motor, which has a 3-D pattern because of the overhang. For the analysis, a new numerical method is developed. The analysis results of this method have been compared with the measured results. Index Terms--3-D analysis method, BLDC motor, slotless winding shape, small sized motor, winding angle.

The harmonics in electromagnetic force are source of the mechanical vibration and the audible noise in an asynchronous traction motor. This paper describes an approach to reduce the force harmonics by changing the rotor slot number. Both the radial and tangential forces acting on the stator teeth are calculated by Maxwell stress tenser and their time harmonics are examined by the discrete Fourier decomposition. As a result, the optimal slot number of the rotor to reduce or eliminate the specific force harmonics is determined. Index Terms--Asynchronous, finite element methods. force, traction motor.

Most single-phase brushless DC (BLDC) motors have unequal air gaps to eliminate the dead point where the developed torque value is zero. These unequal air gaps deteriorate the motor characteristics in cogging torque. Thus in this paper a new topology of the unequal air gaps is proposed to solve this problem. As a result, it is proved by the finite element analysis and experimental results that the proposed air gap topology is very effective in reducing the cogging torque. Index Terms--Brushless DC motor, cogging torque, finite element, unequal air gap.