• Journal of Power Electronics
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• 제15권3호
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• pp.730-740
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• 2015

This paper presents model reference adaptive system speed estimators based on Type-1 and Type-2 fuzzy logic controllers for the speed sensorless direct torque and flux control of an induction motor drive (IMD) using space vector pulse width modulation. A Type-1 fuzzy logic controller (T1FLC) based adaptation mechanism scheme is initially presented to achieve high performance sensorless drive in both transient as well as in steady-state conditions. However, the Type-1 fuzzy sets are certain and cannot work effectively when a higher degree of uncertainties occurs in the system, which can be caused by sudden changes in speed or different load disturbances and, process noise. Therefore, a new Type-2 FLC (T2FLC) - based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties, improve the performance, and is also robust to different load torque and sudden changes in speed conditions. The detailed performance of different adaptation mechanism schemes are performed in a MATLAB/Simulink environment with a speed sensor and sensorless modes of operation when an IMD is operates under different operating conditions, such as no-load, load, and sudden changes in speed. To validate the different control approaches, the system is also implemented on a real-time system, and adequate results are reported for its validation.

• 한국추진공학회지
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• 제2권2호
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• pp.47-55
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• 1998

중형항공기용 터보팬엔진의 설계점, 탈설계점에 대한 정상상태 및 천이상태 성능해석을 수행하였다. 정상상태 성능해석은 설계점으로 선정한 지상최대추력조건과 탈설계점으로 선정한 최대상승조건과 순항조건에서 수행하였으며 부분부하 성능해석 결과 저압압축기 회전속도 90％RPM에서 가장 연료소모율이 적어 경제적임을 확인하였다. 천이상태 성능해석은 각각의 비행조건에서 연료의 Step증가, Ramp증가, Ramp감소, Step 증가 후 Ramp 감소의 경우에 대하여 수행하였다. 천이상태의 성능해석을 위해서는 압축기와 터빈의 일에 대한 조합이 필요한데, 일의 조합방정식에 포함된 잉여 토오크의 적분에는 Modified Euler Method를 적용하였다. 천이상태 성능해석 결과, 모든 비행조건에서 Step 및 Ramp 증가의 경우 고압압축기의 터빈입구온도가 제한온도를 초과하며, 최대상승조건에서 연료를 Step 또는 5.5초 이내의 Ramp 증가시킬 경우 고압압축기에서 실속이 발생함을 확인하였다.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.839-850
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• 2002

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components'characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.

• 수산해양기술연구
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• 제36권3호
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• pp.157-165
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• 2000

연안 소형 어선의 조업 효율을 향상시키기 위한 연구의 일환으로 소형 유압식 어로윈치시스템을 설계하고, auto tension 기능을 내장시켜 이 시스템의 개루프 상태에 대한 동적 응답 특성을 분석, 고찰한 결과를 요약하면 다음과 같다. 1. 본 연구에서 설계, 제작한 소형 윈치시스템은 갑판상 어느 장소에서도 조작이 가능하도록 원격조작방식을 채용하고 있기 때문에 어로 작업시의 인력 감소와 작업의 효율성을 높일수 있다고 생각된다. 2. 솔레노이드 밸브를 ou/off 조작하여 윈치를 구동할 때, 정전 및 역전 구동 조작에 대한 윈치 드럼의 회전 지연시간(dead time)은 각각 0.09 sec, 0.04 sec이었다. 또한 on/off 레버의 조작을 행한 직후 응답 특성은 약간 불안정하였지만, 짧은 경과 시간을 거쳐 안정되는 추종성능을 나타내었다. 3. 윈치를 auto tension mode로서 구동하는 경우, 윈치의 회전축에 55.9 kgf$.$m 이상의 토오크가 작용하면 윈치는 5.1 rpm의 회전속도로서 줄을 풀어내고, 그 이하의 토오크가 작용하면 11.1 rpm의 회전속도로서 줄을 감아들이는 자동 권양 윈치의 기능을 발휘한다. 4. 윈치의 auto tension mode에 대한 과도 응답에서 부하가 급격히 증가할 때와 감소할 때의 정정 시간은 0.12 sec, 0.2sec이었고, 그 때의 회전속도는 각각 11 rpm, 5.3 rpm이었다. 5. 원격제어조작에 따른 윈치의 토오크 및 회전속도에 대한 추종성능은 정전 구동에 있어서는 0.23 sec, 역전 구동의 경우에 있어서는 0.37 sec 이내로서 비교적 안정된 응답 특성을 나타내었다. 이상의 결과로부터 본 연구에서 설계한 소형 어선용 자동 권양 윈치 시스템은 인력을 절감하고, 부하의 급속한 변화에 대한 추종 성능이 현용 어로시스템에 비하여 매우 우수하기 때문에 해상에서 어로작업시 과부하에 대한 어구의 손상 방지 및 조업 효율의 향상에 크게 기여할 것으로 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1647-1650
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• 1997

This paper presents the control law of Automatic Rudder Trim System(ARTS) for the KTX-1. The proposed ARTS is designed mainly t reduce the pilot's work load for trimming in the various conditiions of engine torque. airspeed, and aircraft configuration. The ARTS partially compensates the transient yawing motion due to change of engine power in turboprop aircraft because of the limitation of the actuation speed of the trim motor. In this paper flight test data are analyzed to understand the phenomena and the dynamics of the reversible rudder flight control system is derived. Finally, the control concept and conrtol law of ARTS are described and the characteristics of the ARTS are analyzed through simulation study.

• 제어로봇시스템학회논문지
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• 제2권2호
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• pp.115-120
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• 1996

In this paper, a sliding mode controller which is characterized by high accuracy, fast response and robustness is applied to speed control of AC-SERVO motor. The control input is changed to the continuous one in the boundary layer to reduce the chattering phenomenon, and the boundary layer converges to zero when the state variables of system reach to steady state values. The integral compensator is added to reduce steady state error and to provide the continuous torque reference. The acceleration which is necessary for the sliding plane is estimated by an obsever. Sliding surface is included in control input to enhance the robustness and transient response without increasing sliding mode controller gain. The proposed controller is implemented by DSP(digital signal processor). The effectiveness of the proposed scheme is demonstrated through experimental works.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.173-174
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• 2016

This paper proposes a comparison of Voltage Oriented Control (VOC) and Direct Power Control (DPC) under command mode transition for PMSG Wind Turbines (WT). Based on a neutral point clamped three level back to back type Voltage Source Converter (VSC), proposed control scheme automatically control the generated output power to satisfy a grid requirement from the hierarchical wind farm controller. Automatic command mode transition based on the dc-link voltage error provides a command mode changing between grid command and MPPT mode. It is confirmed through PLECS simulations in Matlab. Simulation result shows that proposed control scheme of VOC and DPC achieves a much shorter transient time of generated output power than the conventional control scheme of MPPT with optimal torque control and VOC under a step response. The proposed control scheme makes it possible to provide a good dynamic performance for PMSG wind turbines in order to generate a high quality output power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2139-2142
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• 1997

The most important thing in vector control scheme is the knowledge of accurate electrical motor parameters. These parameters can computed by conventional motor test, such as no-load and locked rotor tests. However, the values from these tests are different from actual motor parameters, and the adjustment process of the parameters is time consuming. This paper presents an auto-tuning method for vector control of induction motor. The tuning algorithm is based on the rotor flux behavior of the induction motor for stepwise torque current command. The transient terminal voltage caused by the undesirable variation of the rotor flux is used for tuning the slip gain $K_5$ defined as the inverse of the rotor time constant. The electrical parameters of induction motor can also calculated by this method. The presented method is evaluated through the computer simulations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.47-51
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• 1996

In this paper, we propose a method for compliance control of a SCARA type 2-freedom direct drive(DD) manipulator. Each joint of the manipulator is driven by a travelling ultrasonic motor(USM). The travelling USM has good some characteristics over conventional servo motors such as compact size, light weight, silent motion, high torque and high speed response. By controlling the elasticity and viscosity of robot joints, a robot can work in compliance with external environment. we control the elastic coefficient and the viscous coefficient of joint by adjusting the phase difference of the motor power. And we contemplate transient response of USM with adjusting the elastic coefficient and the viscous coefficient. To use the result, we can control the robot to reach its goal with compliance motion. It remains for further research to develop the impedance control of USM.

• 한국정밀공학회지
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• 제31권10호
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• pp.935-945
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• 2014

This paper presents a new road generative system that employs a pad of preventive overspeed or tollgate. The system consists of pad, shaft, torsional damper, oneway-clutch, gear system, and electricity generator components. When the car driven through the road generation system, it occurred to surplus energy in the DC power. In order to maximize the power of electricity energy harvester, the simulation software is developed. It is used to determine parametric dimension for optimal design with the theoretically calculated results from the simulation software. The transient responses at the conditions of low and high vehicle speed are compared with the calculated results as torque, impact force, power, out energy etc. Consequently, before design a road generation system, the analysis of simulation results shows that the proposed concept and system has efficiency and confidence.