• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권4호
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• pp.213-223
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• 2004

In the machine tool industry, direct drive linear motor technology is of increasing interest as a means to achieve high acceleration, and to increase reliability. The advantages of such a motor are that it has a good linearity and has no need of such mechanical energy conversion parts, which change rotary motion into linear motion, as screws, gears, chains etc In this paper, two structures of LOA are analyzed. One is the moving-coil type LOA and the other is moving-magnet type LOA. Two types of LOA are analyzed, with reference to the following parameters as variables: magnetic field, flux linkage, motor thrust and back emf. These variables are derived by the use of analytical method in terms of two-dimensional rectangular coordinate system. The maximum values of thrust according to such design parameters as air-gap length and magnet height for each model is also represented. The results are validated extensively by comparison with finite element method. In particular, we experiment moving-coil LOA which is already manufactured and confirm that the experimental results are shown in good agreement with analysis through the comparison of between analytical and experimental results

• Journal of Power Electronics
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• 제13권6호
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• pp.964-974
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• 2013

A modified direct torque control (DTC) method based on torque angle is proposed for interior permanent-magnet synchronous motor (IPMSM) drivers used in electric vehicles (EVs). Given the close relationship between torque and torque angle, proper voltage vectors are selected by the proposed DTC method to change the torque angle rapidly and regulate the torque quickly. The amplitude and angle of the voltage vectors are determined by the torque loop and stator flux-linkage loop, respectively, with the help of the position of the stator flux linkage. Furthermore, to satisfy the torque performance request of EVs, the nonlinear dead-time of the invertor caused by parasitic capacitances is considered and compensated to improve steady torque performance. The stable operation region of the IPMSM DTC driver for voltage and current limits is investigated for reliability. The experimental results prove that the proposed DTC has good torque performance with a brief control structure.

• 전자공학회논문지
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• 제50권1호
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• pp.254-260
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• 2013

본 논문에서는 IPMSM(Interior Permanent Magnet Synchronous Motor)의 약계자 제어에 따른 전자기적특성을 다룬다. IPMSM의 운전 속도 영역을 확장하기 위해 약계자 전류제어가 일반적으로 사용되며 약계자 운전 중에는 전기강판의 자기적 포화에 의해 쇄교자속의 왜형이 발생하게 된다. 따라서 정현파 전류 입력을 위한 전압 파형은 왜형을 갖게 된다. 약계자 전류 증가에 따라 이러한 전압 왜형은 더욱 크게 발생되며 기본파 전압에 비해 상당한 크기의 고조파 전압을 필요로 하게 된다. 이러한 현상을 ２차원 유한요소 해석을 이용하여 확인하였으며 시험을 통해 검증하였다. 본 연구 결과를 통해 IPMSM의 특성 분석에 사용되는 d-q축 등가회로 파라미터 즉, 영구자석에 의한 쇄교자속, d－q축 인덕턴스는 산정 단계에서 기본파 물리량으로 계산되므로 약계자 운전시 발생하는 전압 왜형을 예측할 수 없음을 알 수 있다. 결국 주어진 전압에서 얻을 수 있는 속도 예측에 오차를 수반하게 되며 전압고조파에 대한 대책이 필요하다.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.185-191
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• 2006

In this paper, a novel stator hybrid excited doubly salient permanent magnet (SHEDS-PM) brushless machine with a special magnetic bridge is proposed for the first time. The originality of this machine is purposely to add a magnetic bridge in shunt with each PM pole, which not only maintains the stator lamination in its entireness, but also amplifies the effect of DC field flux on PM flux. An equivalent magnetic circuit is presented to clarify the novelty. Based on the 2-D finite element analysis, the static characteristics of the SHEDS-PM machine, namely phase flux linkage, back-EMF, cogging torque, winding inductance and static torque are deduced. The corresponding results on a prototype machine illustrate that the proposed machine is promising for application to electric vehicles.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.229-230
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• 2007

We investigated the quench characteristics of a superconducting element, two superconducting elements in order to increase the current capacity of flux lock type SFCL. The flux-lock type SFCL consisted of the transformer with a primary winding and a secondary winding connected in parallel, and the superconducting element was connected with secondary winding in series. The applied voltage at that time was 160 ${\sqrt{3}}$. We found that the parallel connection between the superconducting elements increased the power capacity and let quench characteristics improve through their mutual linkage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.868-870
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• 2001

Salient pole rotor type single phase SRM(switched reluctance motor) can be use axial direction magnetic flux and radial direction magnetic flux at the same time. Then, it has higher energy density per unit volume and can be lessened the shaft length of motor or exciting magnetic force. Additionally, it's durability is good because it is simple structure and driving device. Prototype of Salient pole rotor type single phase SRM was fabricated by using parameters of three phase SRM and 3D FEM analysis. Also, driving device was fabricated for prototype. Speed and torque characteristic was confirmed through the experiments, and flux linkage, which is important parameter of SRM for generating torque, was measured. The induction emf was calculated by using ideal inductance graph and current graph. Calculated emf and measured emf was compared for confirming loss of prototype in this paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.836-839
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• 2003

A pneumatic servo valve which is widely applied in industrial field. And It is consist of force motor, spool ＆ sleeve and servo controller. In this study. we developed the force motor which is consume to low power for a pneumatic servo valve. We could reduce the number of turn of the solenoid by using ferromagnetic permanent magnet and took different direction of each other using one coil instead of two coil. we modeled a system consisting of various electro-mechanical subsystems. The appropriateness of the model was verified by simulation. The simulation model resolved the motion of spool, the winding current and the magnetic force. Also, we calculated the displacement and velocity of the spool, flux contour line, b vector. flux density. flux linkage, back EMF etc.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.304-307
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• 2002

A sensorless velocity control strategy for permanent magnet synchronous motors is presented in this paper. Two stator currents are measured and processed in discrete form in DSP. The rotor position and speed are estimated through the stator flux linkage and its derivative estimation. Flux and its derivative are calculated in the stationary reference frame and used to estimate the speed and position. The closed-loop speed control has been shown to be effective from standstill to rated speed. Moreover, a flux drift problem caused by the integration can be eliminated so that a stable sensorless starting and running operation can be achieved. Experimental results are presented to demonstrate the effectiveness of the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.91-93
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• 2003

Disk type Single Phase SRM(Switched Reluctance Motor) can be used axial direction magnetic flux and radial direction magnetic flux. In this paper, the flux linkage was measured according as rotor positions of disk-tyre single phase SRM, which is designed and manufactured in previous research. From the measured data, we got the magnetization curves, inductance profile and Co-energy.

• Journal of Power Electronics
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• 제16권3호
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• pp.994-1003
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• 2016

Two major obstacles in the utilization of electrical vehicles are their price and range. The collaboration of direct torque control (DTC) with induction motor (IM) is preferred for its low cost, easy implementation, and parameter independency. However, in terms of edges, the method has drawbacks, such as variable switching frequency and undesired current harmonic distortion. These drawbacks result in acoustic noise, reduced efficiency, and electromagnetic interference. A feed-forward approach for stator-flux-oriented DTC with space vector pulse-width modulation is presented in in this paper. The outcome of the proposed method is low current harmonic distortion with fixed switching frequency while preserving the torque performance and simple application feature of basic DTC. The method is applicable to existing and forthcoming IM drive systems via software adaptation. The validity of the proposed method is confirmed by simulation and experimental results.