• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.40-47
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• 2014

Sinusoidal back-EMF waveform of vernier Permanent Magnet (PM) machines is analyzed in this paper. An analytical expression of Electromotive Force (EMF) of electric machines including vernier machines is developed to analyze EMF harmonics, and the effect of vernier PM machine pole ratio, the ratio of number of rotor poles to stator poles, on the EMF waveform. Moreover, this paper represents several Finite Element Analysis (FEA) models to verify the analysis based on the proposed expression, and the effect of tooth width ratio, which is the ratio of tooth width to tooth pitch, on back-EMF of vernier PM machines, and optimal tooth width ratio is obtained and verified by FEA. Finally, this paper makes comparisons between EMF waveform of vernier PM machines and that of traditional PM machines from the point of view of analytical EMF expression.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.4
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• pp.191-194
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• 2007

This study focuses on the development of the Electrochemical type $CO_2$ sensor Module by using solid electrolyte which was first developed in our country. The module applied the creative fundamentals that the voltage state generated from Electro-chemical reaction using new materials is converted into $CO_2$ ppm. The study verified the accurate of Electromotive Force(EMF) through the experiment using high-impedance opamp(INA332) to measure EMF which ranges from 100mV to 600mV to be outputted from $CO_2$ sensor, and the small electric current of some nano-ampere(nA)

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2208-2212
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• 2008

This paper deals with the cost reduction design of a single-phase line-start permanent magnet(LSPM) motor. Due to high cost of the permanent magnet(PM), cost reduction can be effectively achieved by reducing PM volume. Therefore, motor characteristics according to the PM volume are calculated by using d-q axis equivalent circuit analysis, and the characteristic map is made. In the characteristic map, maximum torque and efficiency are shown according to motor parameters such as back electromotive force(back emf) and inductances; back emf represents the PM volume. Minimum back emf and inductances satisfying output performance are determined in the characteristic map. Then, motor geometry based on the prototype motor is optimized to get the determined parameters using response surface methodology(RSM) and finite element method(FEM). Through the presented cost reduction design, total PM volume is reduced to 32% of prototype model.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.750-753
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• 2005

This paper presents a method of detecting rotor position for single phase Switched Reluctance Motors(SRMs) using searchs coil. In the single phase SRM, mainly Hall effect sensors or photo interrupters have been used to detect the rotor position. But these sensors cause high cost and increase the volume of the motor, Furthermore when the motor is used in very hostile environment like high temperature or pressure, its reliability goes down. In this paper, low cost and robust characteristics of rotor position detection method are focused in order to compensate for disadvantage of existing sensors. Search coils wound around the stator pole are used for detection of the rotor position in single phase SRM. Rotor position detection is achieved through electromotive force patterns induced by time-varying flux linkage in the search coil. The validity of the method is verified by experimental results.

• 전기의세계
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• v.29 no.6
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• pp.393-400
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• 1980

It is shown in this paper that it is possible to derive generalized state equations for computation of electrical circults constanining SCR and diode elements. Revankar's binary logic variable method is used for formulation of the state equation of chopper circuit. Advantage of this method is that the state equations can be set up without the exact knowledge of the circuit operaton. The different modes of operation of the circuit are identified by the computer itself. By applying this method, the steady state performances of separately excited chopper-fed dc motor considering the counter electromotive force of the motor are investigated and the results of the computer simulation are presented. There is a satisfactory agreement between the theoretical and experimental results.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1108-1110
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• 2000

The BLDCM(Brushless DC motor) has been the Trapezoidal Back Electromotive Force(EMF) due to a surface magnet rotor with nonlinear distribution and full-pitch windings. Theoretically, it should be fed with rectangular phase current in order to minimize torque ripple. But, because voltage source inverter drives BLDCM, perfectly rectangular phase currents are not available. Now in this paper, using fourier series coefficients, calculating the coefficients of harmonic current within available orders and each harmonic component are controlled on stationary frame. Only using four switches, low cost and small size drive can be made and proposed method will be more useful in industrial. Simulation and experimental results prove the validity of the proposed method.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1130-1132
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• 2000

In this paper, For Control of the speed sensorless induction motor propose the method which is controled the motor by operating two axis current in input current of the inverter. This method determines frequency of inverter in order to stator electromotive force and E/F ratio for the setting magnetic flux, drives for speed control using a voltage power converter of the induction motor by means of voltage fed converter with current control ability.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.84-90
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• 2012

Various methods have been proposed to identify the flux position in an interior permanent magnet synchronous motor (IPMSM) without the use of mechanical sensors. To achieve this, a method that uses both the back electromotive force (EMF) and the saliency to identify the flux position in the IPMSM without the injection of high-frequency components at low speeds has been reported. This method was then extended in order to drive the motor with no load to a light load. We propose a combination of these methods with different proportional-integral (PI) controllers for controlling $di_{dest}$/dt and $di_{qest}$/dt. We also introduce compensation values $F_L$ and $F_H$ to reduce the position error when the estimation rule is being selected.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.134-140
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• 2013

This paper proposes a new design of rotor shape of Interior Permanent Magnet Synchronous Motor (IPMSM) used for agricultural electric vehicle (AEV). The distribution of the residual magnetic flux density at the air gap is modified by rotor surface shape and V-type magnet angle. As a result, cogging torque and physical characteristic have been improved, and back electromotive force (back-EMF) of the suggested model has been improved to be closest to sine wave form compared to initial model. The validity of the proposed rotor shape optimization is confirmed by the manufactured IPM rotor core and measured the performance of the cogging torque.

• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.229-234
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• 1973

The dependence of ionic activity and electrode potential upon electrolyte concentration in ethylenediamine includes the effects of ion-pair formation involving all possible combinations of cations and anions represent in the solution and includes the ion-atmosphere effects of dissociated ions. For calculating activity coefficients, Debye-Huckel limiting law, extended Debye-Huckel,equation, and Marshall Grunwald equation were used in comparison of experimental and calculated plots of the electromotive force of the cell versus the logarithum of concentration. The fit of the experimental points to the theoretical curves was improved in case of the Marshall-Grunwald equation.