• 전자공학회논문지SC
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• 제41권3호
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• pp.25-32
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• 2004

본 논문에서는 두 개의 사인파 신호의 위상 차이를 계산해 내기위한 개선된 위상 측정 알고리즘을 제안하였다. 이 알고리즘은 두 개의 입력신호의 양자화된 샘플링 데이터를 사용하여 위상과 크기를 구해낸다. 측정 알고리즘의 중요 파라메타들은 몇개의 해석식으로 표현되기 때문에 위상을 계산하기 위해 필요한 연산량이 상당히 줄어들고 따라서 더 빠른 속도로 위상을 계산해 낼 수 있게 되었다. 또한 본 논문에서 제시한 알고리즘을 사용하여 입력신호의 한주기 전체를 샘플링할 경우에는 입력신호에 harmonic distortion이 발생하더라도 위상 측정 오차가 전혀 발생하지 않음을 수식으로 증명하였으며 컴퓨터 시뮬레이션을 통하여 이를 확인하였다. 그리고 입력신호에 가우시안 백색 잡음(white gaussian noise)이 발생할 경우에 위상 측정 오차가 얼마나 발생하는 지에 대하여 여러 가지 관점에서 컴퓨터 시뮬레이션을 수행하고 그 결과를 분석하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.274-278
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• 2005

Voltage transformer(VT) comparison measurement system is usually used for measurements of ratio error and phase angle error of VT made in industry. Both ratio error and phase angle error in VT are critically influenced by values of burden of VT used. External burden effects on both ratio error and phase angle error in VT are theoretically calculated. From the theoretical calculation, a method of evaluation for linearity of ratio error and phase angle error in VT measurement system have been developed using the standard capacitive burdens, with negligible dissipation factor less than 10$^{-4}$. These burden consists of five standard capacitors, with nominal capacitance of 1.1 $\mu$F, 1 $\mu$F, 0.1 $\mu$F, 0.01 $\mu$F, 0.001 $\mu$F. The developed method has been applied in VT measurement system of industry, showing in good consistency and linearity within 0.001 $\%$ between theoretical and measured values.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권9호
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• pp.470-474
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• 2004

Both ratio error and phase angle error in voltage transformer(VT) depend on values of burden of VT used. A method of evaluation for linearity of ratio error and phase angle error in VT measurement equipment have been developed using the standard resistance burdens, with negligible AC-DC resistance difference less than $10^-6$. These burden consists of five standard resistors, with nominal resistance of 100 $\Omega$, 1 k$\Omega$, 10 k$\Omega$, 100 k$\Omega$, and 1 M$\Omega$. The developed method has been applied in VT measurement equipment of industry and the validity of the developed method has been verified by showing the consistency of the result of linearity obtained using VT with wide ratio error.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권3호
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• pp.134-141
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• 2006

A potential transformer(PT) has ratio error and phase angle error. Precise measurement of the errors of PT can be achieved using high voltage capacitance bridge, high voltage capacitor and low voltage capacitor. The uncertainty for this method is evaluated and found to be $20{\times}10^{-6}$ in both ratio error and phase angle error. The values measured for PT using the method are well consistent with the those measured for same PT in NMIA(National Measurement Institute of Australia) within the corresponding uncertainty.

• Journal of Electrical Engineering and Technology
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• 제8권6호
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• pp.1345-1351
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• 2013

Variable iron loss as function of current phase angle of Interior Permanent Magnet Synchronous Motor(IPMSM) was calculated through Curve Fitting Method(CFM). Also, a magnetic flux density distribution of iron core according to current phase angle was analyzed, and an iron loss calculation was performed including harmonic distortion. The experiment was performed by production of non-magnetizing model for the separation of mechanical loss, and the iron loss was calculated by the measurement of input using power analyzer and output power using dynamometer. Some error was generated between experimental results and calculation value, but an iron loss diminution according to current phase angle followed a same pattern. So, errors were generated by measurement, vibration, noise, harmonic distortion loss, etc.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제53권4호
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• pp.213-217
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• 2004

A current transformer(CT) used for the estabilishment of high current national standard, has generally very small ratio error and phase angle error. Both the errors of CT depend critically on the external burden used. When both the ratio and phase angle errors at two different burdens including zero burden are known, those at any other burdens are calculated theoretically. The theoretical values are well consistent with the experimental results within the $82{\times}10$-6, implying the measurement system of CT in KRISS is well maintained.

• 한국의학물리학회지:의학물리
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• 제3권2호
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• pp.43-57
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• 1992

위상감지법(phase detector technique)은 세포의 막 캐패시턴스(membrane capacitance)를 실시간적으로 측정할 수 있는 유일한 방법이나 측정이 행해지는 동안 세포의 상태가 끊임없이 변화하기 때문에 피할 수 없는 측정오차가 존재한다. 본 연구는 이 오차의 근원을 분석하여 위상감지법의 실용한계를 규정하고자 하였다. 이론적 분석에 기초하여 다음과 같은 사실을 밝힐 수 있었다. 1) access conductance와 membrane conductance의 변화에 기인하는 측정오차를 줄이기 위해서는 초기 위상치를 올바로 선택하여야 한다. 2) 이 때 세포를 여기시키기 위해 인가하는 전압의 주파수를 알맞게 선택하여야 한다. 3) 그러나 초기 위상치가 정해진 이후의 위상 변화는 막 캐패시턴스의 측정에 큰 영향을 미치지 않는다. 4) 초기 위상을 적절히 선택하였다 하더라도 세포외 분비시 막 캐패시턴스가 크게 증가하는 경우에는 비례상수에 오차가 발생한다. 이 때 발생하는 오차는 측정기간 동안 비례상수를 되풀이하여(iteration) 보정함으로써 방지할 수 있다. 이상의 결과는 향후 위상감지법을 사용할 때 유용한 설용한계를 제공하리라 생각된다.

• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.619-625
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• 1997

In this paper, we show that the rotor position of the bifilar-wound hybrid stepping motors for the closed-loop drives is detected by the phase current measurement. We propose an instantaneous phase current equation, which is the function of electrical angle, by modeling the stepping motor including motor driving circuits. We also analyze the relationship between phase current and rotor position from the computer simulation results. We show that the information about the rotor position is obtained from the phase current amplitude and its derivatives at the instance of ${\pi}/2$ electrical angle of excitation voltage.

• 대한조선학회논문집
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• 제57권3호
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• pp.160-167
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• 2020

A two-stroke diesel engine and a propeller normally adopted in large merchant ships are regarded as major ship vibration sources. They are directly connected and generate various excitation components proportional to the rotating speed of diesel engine. Among the components, the magnitude of two excitation components with the same frequency generated by both engine and propeller can be compensated by the adjustment of their phase difference. It can be done by the optimization of propeller assembly angle but requires a number of burdensome trials to find the optimal angle. In this paper, the efficient estimation method to determine optimal propeller assembly angle is proposed. Its application requires the axial vibration measurement in sea trial and the numerical vibration analysis for propulsion shafting which can be substituted by additional vibration measurement after one-trial modification of propeller assembly angle. In order to verify the validity of the proposed method, the phase difference between two fifth order excitation components generated by both diesel engine and propeller of a real ship is calculated by the finite element analysis and its result is indirectly validated by the comparison of axial vibration responses at intermediate shaft obtained by the numerical analysis and the measurement in sea trial. Finally, it is numerically confirmed that axial vibration response at intermediate shaft at a resonant speed can be decreased more than 87 % if the optimal propeller assembly angle determined by the proposed method is applied.

• 전력전자학회논문지
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• 제15권3호
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• pp.252-258
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• 2010

레졸버에 의한 속도 측정과 PWM 신호 발생을 하나의 마이크로콘트롤러를 이용하여 동시에 구현하면 시스템 비용을 줄일수 있을 뿐만 아니라 인버터의 스위칭 노이즈를 회피하는 것이 용이하다. 스위칭 노이즈를 회피하면서 동시에 속도측정 정밀도를 높이기 위하여 PWM 스위칭과 레졸버 신호의 A/D 변환 시점이 동기되어야 한다. 본 연구에서는 레졸버 여자신호의 위상을 단계적으로 변화시키면서 레졸버 출력신호를 측정하고, 측정된 데이터로부터 최소자승근사법을 이용하여 레졸버 여자신호의 최적 위상을 추정하였다.