• Journal of Advanced Marine Engineering and Technology
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• 제36권6호
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• pp.837-843
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• 2012

비동기 전동기는 여러 분야에서 널리 사용되고 있으며, 특히 전원공급에 비해 많은 전력을 사용하는 전동기의 경우 이를 기동하기 위해서는 다양한 기동방법이 적용되고 있다. 전동기 기동방법은 주로 회전자에 가변저항을 삽입하거나 고정자에 공급하는 전압을 감소시키는 방법이 사용되고 있다. 이와 같이 기동시 가변저항을 변경하거나 전압을 변경하기 위해서는 특정 단계에서 특정한 시간이 필요하게 된다. 이 시간을 스위칭시간이라 부르며, 이 시간을 정확히 파악하는 것은 매우 어려운 부분이다. 이 시간은 전동기의 부하특성이나 그 형식에 따라 변화한다. 따라서 본 논문에서는 전동기와 부하의 수학적 모델의 개발과 설계에 대해서 알아보고, 전동기의 기동에 필요한 스위칭시간을 계산하기 위해 SIMULINK를 활용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과는 다양한 전동기와 부하를 가진 시스템에 가장 적절하고 적용 가능한 기동 시간을 얻는데 활용할 수 있도록 비교 검토되었다.

• 전력전자학회논문지
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• 제2권3호
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• pp.37-43
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• 1997

2상 하이브리드 스텝모터를 미세스텝으로 제어하면 저속에서도 부드럽게 회전하고, 스텝 분해능을 높일 수 있으며, 공진으로 인한 바람직하지 못한 현상들을 제거할 수 있다. 본 논문에서는 고성능 미세스텝 구동회로를 개발하였다. 본 논문에서 개발한 미세스텝 구동회로는 2상 하이브리드 스텝모터의 1회전스텝(1.8도)을 128 미세스텝으로 구동할 수 있는 위치 분해능을 가지며 스텝모터를 장시간 구동할 때 발생되는 열로 인한 문제점을 줄이기 위한 전류 절약 동작모드를 지원한다.

• 대한전자공학회논문지
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• 제25권3호
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• pp.269-275
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• 1988

In this paper, a high efficiency motor drive system which improves the multi-step response of PM step motors by reducing the transition time of the motor drive current, is studied by designing a dual-voltage drive circuit. The designed drive circuit eventually prevents the motor from decreasing drive torque while the stepping rate is increased. The method of designing a dual-voltage drive circuit with the motor specifications is suggested in order to improve the response of step rate and drive efficiency. Also, despite improving the power efficiency on motor driving, the response characterstics suggested by the motor manufacture's specifications are satisfied without any special deficiency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.37-39
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• 1998

The hybrid step motor has found applications in a wide range of mechanical systems as a low cost, open-loop positioning device. The step motor provides good stiffness at rest against disturbing load influences, a combination of moderate speed fine resolution, high reliability and simplicity. In recent years, considerable competition has arisen over the technological issue of wheather the device should be applied as a 2-Phase or 5-Phase machine. In this paper, to compare two systems, we have atempted to derive the mathematical. model, and analysed operating detent torque with this model. The analysis shows that a fundamental component of the permeance distribution produces the average torque and that harmonic components produce the ripple torque.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.416-423
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• 한국공작기계학회논문집
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• 제13권5호
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• pp.30-37
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• 2004

This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m／min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.88-94
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• 2005

A swirl ratio of a charge in the cylinder could be calculated by measuring both the rotary speed of paddle and the intake air flow rate in the swirl measurement apparatus fur several positions of valve lift. The automation of the swirl ratio measurement for a cylinder head is achieved by controlling both the valve lift of cylinder head and a suction pressure of the surge tank, instead of controlling them manually. PID control of the surge tank pressure and positioning a valve lift of the cylinder head are also achieved by using two step motors, respectively. Rotating speed of a paddle are measured using an optical sensor and a counter. Flow rate are measured from ISA 1932 flow nozzle by reading a differential pressure gauge position using IEEE-1394 camera. Time to measure the swirl ratio for a port in the cylinder head is drastically reduced from an hour to 3 minutes by automation control of the apparatus.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.977-980
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• 1993

The technique to design high performance small motors has been based on experimental data, which results from lots of cost, experience and time in manufacturing. Recently, as high-performance computer appears, many engineers use numerical methods to design and analyze electric machine. Since, the step motor which has very small air gap(0.02-0.05mm) is different from other electric machine in its structure. The shape of rotor teeth and stator teeth influence seriously on the torque characteristics. And it is operated over magnetic saturation point. Therefore, the design of step motor needs to solve nonlinear problem and to calculate magnetic field precisely. In this paper, we solve nonlinear problem by employing Finite Element Method and obtain torque-displacement characteristics for the design of step motor. We also manufacture VR step motor according to the obtained results, and measure some torque characteristics. Through comparing calculated results with experimental results, it is verified that FEM is very useful to design step motor, and the motor designed by our technique is improved in its step accuracy.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.371-374
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• 2004

Induction motors are a critical component of many industrial processes and are frequently integrated in commercially available equipment. Safety, reliability, efficiency, and performance are some of the major concerns of induction motor applications. Preventive maintenance of induction motors has been a topic great interest to industry because of their wide range application of industry. Since the use of mechanical sensors, such as vibration probes, strain gauges, and accelerometers is often impractical, the motor current signature analysis (MACA) techniques have gained murk popularity as diagnostic tool. Fault tolerant control (FTC) strives to make the system stable and retain acceptable performance under the system faults. All present FTC method can be classified into two groups. The first group is based on fault detection and diagnostics (FDD). The second group is independent of FDD and includes methods such as integrity control, reliable stabilization and simultaneous stabilization. This paper presents the fundamental FDD-based FTC methods, which are capable of on-line detection and diagnose of the induction motors. Therefore, our group has developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. This paper presents its architecture. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module is checking stator current, voltage, temperatures, vibration and speed of the motor. The DSPs share information from each sensor or DSP through DPRAM with hardware implemented semaphore. And it communicates the motor status through field bus (CAN, RS485). From the designed system, we get primitive sensors data for the case of normal condition and two abnormal conditions of 3 phase induction motor control system is implemented. This paper is the first step to drive multi-motors with serial communication which can satisfy the real time operation using CAN protocol.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.675-682
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• 2009

Instead of direct driving like BLDC, the induction principle is adopted as a driving one for planar stage. The stage composed of four linear induction motors put in square type is activated by two-axial forces; low-frequency attractive force and thrust force of the linear induction motors. Here, the modified vector control whose new inputs are q-axis current and dc current biased to three phase current instead of d-axis current or flux current is applied extensively to overall motion of the stage. For the developed system, the precision step test and the constant velocity test are tried to guarantee its feasibility for TFT-LCD pattern inspection. However, to exclude a discontinuity due to phase shift and minimize a force ripple synchronized with the command frequency, the initial system is revised to the antagonistic structure over the full degree of freedom. Concretely describing, the porous air bearings guide an air-gapping of the stage up and down and a pair of liner induction motors instead of single motor are activated in the opposite direction each other. The performances of the above systems are compared from trapezoid tracking test and sinusoidal test.