• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.25-32
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• 2004

An advanced algorithm for measurement of phase angle between two sinusoidal signals is proposed in this paper. This algorithm uses discrete sample data of two input signals for calculation of phase angle and amplitude. And the key parameters of the measurement algorithm are described by analytical express, so the calculation of phase angle is simplified. In this paper it is proved that harmonic distortion of the input sinusoidal signals does not affect the measurement value of phase angle by using the proposed algorithm when a whole cycle is sampled. And measurement error by the white Gaussian noise is very small compared by other algorithms.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.6
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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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.9
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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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.3
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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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• v.8 no.6
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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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.4
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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.

• Progress in Medical Physics
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• v.3 no.2
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• pp.43-57
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• 1992

Phase detector techique provides a unique probe to membrane recycling phenomenon by enabling dynamic monitoring of cell membrane capacitance. However, it has inherent errors due to constant changes in measurement environments. The present study analyzed several error sources to develope application criteria of this technique. and the following was found based on a theoretical analysis. The initial phase angle has to be appropriately selected to minimize the error due to perturbation of access and membrane conductances. Excitation frequency is also important to determine the initial phase angle. However. deviation of the phase angle from a predetermined initial value during the measurement period does not affect capacitance estimation to a significant degree. Despite an appropriate initial phase selection an error in scaling factor is expected for a large increase in capacitance during exocytosis. which may be overcome by iteratively correcting the scaling factor over the measurement period. These results will provide a useful guideline in practical application of this technique.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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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.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.3
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.3
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• pp.252-258
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• 2010

If the speed measurement of resolver and the generation of PWM signals are implemented with single microcontroller, it is easy to reduce the system cost and to avoid the switching noise of inverters. To avoid the switching noise and to improve the accuracy of measurement, PWM switching and A/D sampling of the resolver should be synchronized. Phase angle of the resolver excitation signal is increased in stepwise manner, then, the output signal of the resolver is measured in each step. From the measured data, the optimal phase angle of resolver excitation signal is estimated using the least square approximation method.