• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.882-884
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• 2002

The transient voltage characteristics of capacitor self-exited induction generator are analyzed by the state equation which is obtained from the d-q axis equivalent circuit of stationary reference frame and torque equation. The d-q equivalent circuit is composed using the condition of stationary reference frame. The mutual inductance is only considered as a function of magnetizing current in the equivalent circuit. The characteristics are analyzed and discussed by the backward Euler method for various load conditions under specified initial conditions and input.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.26-31
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• 2011

In this paper, torque characteristics analysis of Synchronous Reluctance Motor with the cylindrical rotor type by winding function theory(WFT) is described. The stator is same as one of the induction motor. From the d-axis, q-axis flux density distribution, to calculate self and mutual inductances needed to calculate the torque of the machine by using winding function theory the new equivalent geometry of rotor was proposed. D-axis, q-axis flux densities, self inductance and torque characteristics were obtained. From the comparison with results of finite element analysis the proposed method was verified.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.11
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• pp.577-582
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• 2004

In this paper, lumped equivalent circuits for a conventional parallel directional coupler are proposed. This equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of parallel-coupled line. By using the derived design formula, we have designed the 3dB and 4.7dB MMIC couplers at the center frequency of 3.4GHz and 5.6GHz respectively. Measurements for the designed MMIC directional couplers show at 4dB and 5.2dB-coupling value at the center frequency of 3.4GHz and 5.6GHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper

• ETRI Journal
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• v.31 no.6
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• pp.755-764
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• 2009

This paper presents a switched self-biasing and a tail current-shaping technique to suppress the 1/f noise from a tail current source in differential cross-coupled inductance-capacitance (LC) voltage-controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 ${\mu}m$ CMOS process. The measured phase noise is -117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.

• ETRI Journal
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• v.30 no.4
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• pp.615-617
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• 2008

A novel and compact elliptic-function bandpass filter is proposed in this letter. The techniques of slot etching and the addition of open stubs are applied to enhance the self-inductance and self-capacitance of hexagonal open-loop resonators. Thus, size reduction and improved transmission performance are obtained. Compared to the performance of the conventional design, the central frequency and insertion loss are reduced by 28% and 3.1 dB, respectively. Measurements show that the proposed filter has a fraction bandwidth of 23% at the central frequency of 1.84 GHz, and its insertion loss in the passband is less than -1.5 dB. The bandpass filter occupies only 12 mm${\times}$21.2 mm (approximately $0.24{\lambda}_g{\times}0.14{\lambda}_g$).

• Journal of Magnetics
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• v.18 no.3
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• pp.260-267
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• 2013

In this paper a general 2-D model of a large air-gap synchronous machine either with non-magnetic or magnetic core rotor is investigated and electrical characteristics of the machine are analytically calculated. Considering the general model, analytical equations for magnetic field density in different regions of the large air-gap machine are calculated. In addition, self and mutual inductances in the proposed model of the machine have been developed, which are the most important parameters in the electromagnetic design and transient analysis of synchronous machines. Finite element simulation has also been performed to verify the obtained results from the equations. Analytical results show good agreement with FEM results.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.173-175
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• 2004

This paper presents a novel design of a self tuning PI controller of induction motor using fuzzy control. In this approach, the fuzzy tuning of a PI controller gains is achieved through fuzzy rules deduced from many robustness simulation tests applied to several induction motors, for a variety of operating conditions such as response to speed command from standstill, step load torque application and speed variations, with nominal parameters and an changed rotor resistance, self inductance and inertia. Simulation results on a speed controller of induction motor are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.682-684
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• 2015

A 12/14 bearingless switched reluctance motor (BLSRM) with hybrid stator poles has been proposed due to the outstanding decoupling characteristics between the torque and suspending force. However, the motor is a two-phase motor. The output torque of the motor has torque dead zone and high torque ripple. Hence, the motor cannot self-start at some rotor positions. To solve the self-starting problems and reduce the torque ripple, a stepped rotor is proposed in this paper. Then, the motor with the stepped rotor is optimally designed. In the new designed motor, the majority parameters are kept the same with those of original motor; only the torque pole arc and rotor pole shape are optimally designed. The characteristics of the redesigned motor, such as inductance, torque and suspending force, are analyzed and compared with those in the original motor. Finally, the effectiveness of the proposed method is verified by the simulation results.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.191-193
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• 2005

This paper presents Hybrid PI controller of IPMSM drive using fuzzy adaptive mechanism(FAM) control. To increase the robustness, fixed gam PI controller, Hybrid PI controller proposes a new method based self tuning PI controller. Hybrid PI controller is developed to minimize overshoot and settling time following sudden parameter changes such as speed, load torque, inertia, rotor resistance and self inductance. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.110-113
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• 2008

Embedded capacitor technology is one of the effective packing technologies for further miniaturization and higher performance of electric packaging system. In this paper, the embedded capacitors were simulated and fabricated in 8-layered printed circuit board employing standard PCB processes. The composites of barium titanante($BaTiO_3$) powder and epoxy resin were employed for the dielectric materials in embedded capacitors. Theoretical considerations regarding the embedded capacitors have been paid to understand the frequency dependent impedance behavior. Frequency dependent impedance of simulated and fabricated embedded capacitors was investigated. Fabricated embedded capacitors have lower self resonance frequency values than that of the simulated embedded capacitors due to the increased parasitic inductance values. Frequency dependent capacitances of fabricated embedded capacitors were well matched with those of simulated embedded capacitors from the 100MHz to 10GHz range. Quality factor of 20 was observed and simulated at 2GHz range in the 10 pF embedded capacitors. Temperature dependent capacitance of fabricated embedded capacitors was presented.