• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1115-1119
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• 2007

Five control methods (Speed Control, PID Gain Scheduling, Loop Time Control, Simple PID, Switching Control) have been applied to the control of an Inline Co-axial valve by the simulation of AMESim. The simulation results have shown that the speed control method is the most stable and the fastest way to reach to the set point in the simulation of the flow control. Moreover, It has been found that the five control methods have the almost same characteristics in the power consumption, the counter electromotive force, and the motor angular velocity. According to the analysis results, the fast and stable control characteristics of the speed control method is the most suitable for the flow control using a inline co-axial valve with a DC(BLCD) motor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.652-655
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• 1996

This paper develops an AC motor controller for applications. The AC motor controller is designed based on the variable structure control method and a variable structure disturbance observer is added to reduce the effects of exogenous disturbances. The designed controller is installed on the z-axis of a CNC machining center and milling experiments were performed. The results show improved performance on both position and speed tracking, when compared to the factory-designed servo controller.

• 한국정보통신학회논문지
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• 제9권8호
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• pp.1840-1846
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• 2005

본 논문에서는 유전 알고리즘을 사용하여 PID의 각 계수를 자동적으로 조정함으로써 DC 서보모터의 속도제어에 적용하였다. DC 서보모터는 산업현장 및 로봇분야에 널리 적용되고 있으며 적절한 제어성능을 얻기 위하여 많은 시행착오에 의한 다양한 제어방법이 사용되고 있다. 그러나 산업현장, 플랜트의 변화 및 외란에 강인한 제어알고리즘을 선택하기가 매우 어려우며 많은 시행착오를 통하여 원하는 계수값을 얻어 낼 수 있다. 따라서 본 논문에서는 이러한 문제점을 해결하고 DC 서보모터의 제어성능을 향상시키기 위하여 유전 알고리즘을 적용함으로써 우수한 응답특성을 얻을 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.741-744
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• 2002

The closed circuit pump is applied to control rotating speed and direction of hydraulic motor in hydrostatic transmission. To development of this pump, first of all the servo control regulator has to be designed. Mechanical-hydraulic type servo control mechanism is excellent to be compared with electronic-hydraulic type servo control valve to reliability and economy. In this paper to development positive and negative variable displacement type servo regulator, the hydro-mechanical servo control mechanism is calculated and designed with force balance of pilot piston and position feedback of servo piston.

• 조명전기설비학회논문지
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• 제19권3호
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• pp.66-74
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• 2005

최근 급속도로 발전되고 있는 산업분야에서 서보시스템은 빠른 응답특성과 고도의 정밀성이 요구되고 있다. 이러한 특성의 요구로 인하여 산업용 서보전동기 구동시스템에 고정자 혹은 회전자 자속벡터의 순시위치와 고정자 전류를 검출하여 좌표변환에 의해 고정자 전류를 여자성분과 토크성분으로 분리 제어하는 벡터제어 이론이 많이 적용되고 있다. 벡터제어에서는 좌표변환과 SVPWM 발생을 위해 많은 연산을 요구하므로 디지털 제어시스템에서 DSP에 많은 부담을 주고 있다. 그러나 직접토크제어(DTC) 알고리즘은 디지털 제어 구조로 토크와 고정자 자속 성분의 전류제어에 룩업 테이블을 사용하므로 벡터제어처럼 많은 제어기와 복잡한 연산을 필요로 하지 않고, 동적 응답특성이 전동기의 정수변화에 영향이 적으면서 직접 전동기의 토크와 고정자 자속을 독립적으로 제어할 수 있는 장점을 가진다. 따라서 본 논문에서는 표면 부착형 영구자석 동기전동기(SPMSM)를 사용하여 DTC에 의한 서보 전동기 제어와 벡터제어에 의한 서보 제어시스템 결과를 비교하여 직접토크제어 알고리즘의 산업용 서보 시스템으로의 적용 가능성을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제17권1호
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• pp.26-32
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• 1993

The loads exerted on electro-hydraulic servo system are classified into inertial, viscous, and spring load. The additional load called disturbances is also exerted on system but is generally not modeled. To deal with these kinds of loads, it is necessary to maintain the continuous signal transfer, so we can construct compensator to satisfy control specifications using feedback signal such as displacement, velocity, acceleration and pressure known as state variables. In case of controlling the speed of hydraulic motor, we must keep up robust performance for the various loads and disturbances acted on the system. However, the load flow rate in the valve is characterized by nonlinearity so that traditional theory of linear control could not be expected to give the desired performance. In this paper, it is shown that speed controller of hydraulic motor gives a good command following and disturbance rejection performance by applying sliding mode theory as a way of robust control to the nonlinearity, variation of loads and disturbances.

• Journal of Power Electronics
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• 제15권1호
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• pp.246-255
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• 2015

This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.

• 대한전자공학회논문지
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• 제23권6호
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• pp.888-894
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• 1986

In this paper, a phase locked loop control system is designed to have high performance and stability in a 2-phase bifilar winding PM step motor. The BODE diagram analysis method is used to improve the stability and dynamic characteristic of the closed loop control system. Also, a PLL servo is used to accomplish high-precision speed and to attain smooth ness. In applying the PLL control to the step motor, a new design method is suggested to solve the control problem which occurs as a result of the limited maximum acceleration of the step motor. A simple design method is suggested without using the complicated multi-step characteirstic of the step motor in constant voltage driving. Computer simulation results agree clorelg with experiments, indicating that the PLL servo system of the step motor designed is very useful.

• Journal of Power Electronics
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• 제9권3호
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• pp.499-506
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• 2009

In this paper, the initial pole-position estimation of a surface (non-salient) permanent magnet synchronous motor is mathematically analyzed and surveyed on the basis of simulation analysis, and developed for accurate servo motor drive. This algorithm is well carried out under the full closed-loop position control without any pole sensors and is completely insensitive to any motor parameters. This estimation is based on the principle that the initial pole-position is simply calculated by the reverse trigonometric function using the two feedback currents in the full closed-loop position control. The proposed algorithm consists of the predefined reference position profile, the information of feedback currents, speed, and relative position, and the reverse trigonometric function for the initial-pole position estimation. Comparing with the existing researches, the mathematical analysis is introduced to get a more accurate initial pole-position of the surface permanent magnet motor under the closed-loop position control. It is found that the proposed algorithm can be easily applied in servo drive applications because it satisfies the following user's specifications; accuracy and moving distance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.413-418
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• 1998

We often use induction motor in the hard environment including vibration and high ambient temperature, or in maintenance free operation, because induction motor has durable and simple structure. However, when we use it as servo actuator or accurate speed control motor, we have to equip sensor such as encoder and tachogenerator with the motor control system. And generally those sensor's abilities against bad environment are less than the induction motor itself, So if we can remove these sensors from the system, it'll have more environmental resistance, and the cost will also be reduced. Actually this removal has been achieved in limited field. However, that needs complex calculations and a certain elapse time for data processing. In our study, we intended to estimate the rotational speed from the motor current instead of speed sensor, easily and rapidly in comparison to former methods.