• 한국정밀공학회지
• /
• 제18권3호
• /
• pp.189-194
• /
• 2001

This paper presents a mew design of an inductive position sensing system with high sensitivity. The designed system consists of the driving coils, position-detecting coils, and closed loop formed magnetic blocks. To obtain high sensitivity we design a symmetric and closed loop type measuring system with small air-gaps. The elements that affect the system characteristics are turn ratio, excitation frequency, air-gap size, capacitance effect, and load resistance. By experimental investigation, the influences of these elements are examined and the system parameters are selected. The sensitivity of the newly designed system is greater than 2800mV/(V mm) and the linearity error is below${\pm}0.01%; in; the; range; of; {\pm}200{\mu}m$.

• 센서학회지
• /
• 제9권4호
• /
• pp.268-273
• /
• 2000

본 논문은 박막 히터형 유량센서의 온도보상을 위해 초기 불평형 전압을 이용한 새로운 온도보상 방법을 사용하였다. 온도보상을 위해서 본 논문에서는 휘스튼 브릿지의 비를 다르게 하는 방법으로 오픈루프에서 초기 불평형 전압을 온도에 따라 나타낸 그래프를 이용하여 센서 회로의 저항값을 구하는 방법을 사용하였다. 공기 온도가 $-20^{\circ}C{\sim}120^{\circ}C$ 범위에서 온도 보상을 실시한 결과 ${\pm}1%$이내의 온도 오차가 발생하여, 정밀한 박막 히터형 유량 센서를 제작할 수 있었다.

• 융합신호처리학회 학술대회논문집
• /
• 한국신호처리시스템학회 2006년도 하계 학술대회 논문집
• /
• pp.77-80
• /
• 2006

This paper based on spiral vector, three phase induction motor is described a detailed modeling by a phase segment methode. Based on this model, A torque control and the equation of regenerative power for the induction motor drive, based on the field acceleration method(FAM), is presented. The speed control system is designed to be applied voltage source inverters that is easy the current type feedback of power regeneration for motor drive. The ability of shaving power to be measured power regeneration has been investigated in speed acceleration and reduction. And it is change of stator resistance that the voltage commands include error, the ripple of exited voltage and torque occur from the results. The experimental tests verify the performance of the proposed regenerative drive for FAM, proving that good behavior of the drive is achieved in the transient and steady-state operating conditions.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권10호
• /
• pp.522-527
• /
• 2003

This paper proposes a new speed and flux estimation method which has the robustness against the variation of the electrical parameters of the motor and the superiority in the dynamic characteristics. In the proposed method, the stator currents and the rotor fluxes are observed on the stationary reference frame using the sliding mode concept. And the rotor speed is estimated using the current estimation errors and the observed rotor fluxes based on the Lyapunov stability theory. Also a design method of the observer gain is proposed to minimize the effect of the speed estimation error on the rotor flux observation. The experimental results are shown to verify that the proposed method shows the excellent performances under the variations of motor resistance and inductance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 학술대회 논문집 전문대학교육위원
• /
• pp.113-115
• /
• 2001

This paper presents the rotor parameter identification based on the MRAS theory and the speed estimation using ANN for the sensorless vector control of induction motor. The motor speed is estimated using ANN model which contains the rotor parameter. And the rotor parameter is identified using MRAS scheme which contains the rotor speed. The rotor speed estimate converges to its actual value as the rotor parameter error converges toward the zero. The simulation using Matlab/Simulink is performed to show the effectiveness of the proposed scheme.

• ETRI Journal
• /
• 제29권1호
• /
• pp.70-78
• /
• 2007

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.

• 전기학회논문지
• /
• 제64권8호
• /
• pp.1217-1223
• /
• 2015

In this paper, we study the problem of torque ripple minimization in Brushless DC Motors (BLDC) and proposes a disturbance observer (DOB) based controller in order to efficiently reduce the torque ripple. In the DOB based control system, an equivalent disturbance (plant disturbance and effect of modelling error) is cancelled by its estimate. When the DOB controller is applied to BLDC motors, the effect of inverter switching is considered as an equivalent disturbance and to be cancelled by the DOB controller. Through computer simulations, it is shown that the performance of the proposed DOB controller is superior to that of the conventional PI controller. In the case where the numerical values of resistance and inductance are not known exactly, it is shown that the proposed DOB controller achieves better performance than the PI controller.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 A
• /
• pp.205-207
• /
• 2003

The line impedance is important data that is applied in all analysis fields of electric power system like power flow, fault current, stability and relay calculation etc. Usually, impedance can be accurately calculated in case of overhead line. However, in case of power cables or combined transmission lines, impedance can not be accurately calculated because cable systems have the sheath, grounding wires, and earth resistance. Therefore, if there is a fault in cable system, these terms will severely be caused much error to calculation of impedance. Therefore, the line impedance were measured for this study in an actual power system of underground cables, and were analyzed by a generalized circuit analysis program EMTP for comparison with the measured value. These analysis result is considered to become foundation of impedance calculation for underground cable.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
• /
• pp.30-31
• /
• 2019

Carbonation of the root concrete reduces the durability of the reinforced concrete, and it is important to check the carbonation resistance of the concrete to ensure the durability of the reinforced concrete structure. In this study, a basic study on the prediction of carbonation progress was conducted by considering the mixing conditions of concrete using deep learning algorithm during the theory of artificial neural network theory. The data used in the experiment used values that converted the carbonation velocity coefficient obtained from the mixing conditions of concrete and the accelerated carbonation experiment into the actual environment. The analysis shows that the error rate of the deep learning model according to the Hidden Layer is the best for the model using five layers, and based on the five Hidden layers, we want to verify the predicted performance of the carbonation speed coefficient of the carbonation test specimen in which the exposure experiment took place in the real environment.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.640-645
• /
• 2007

An experimental apparatus to show the hot spot cooling of an IC chip using a thermoelectric cooler is developed. The spot heating in very small area is achieved by the applying CO$_2$ laser source and temperatures are measured using miniature thermocouples. The active effects of thermoelectric cooler on the hot spot cooling system such as rapid heat spreading in the chip and lowering the peak temperature around the hot spot region are investigated. The experimental results are simulated numerically using the TAS program, which the performance characteristics such as Seebeck coefficient, electrical resistance and thermal conductivity of the thermoelectric cooler are searched by trial and error. Good agreements are obtained between numerical and experimental results if the appropriate performance data of the thermoelectric cooler are given.