• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.231-233
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• 1994

We have studied a properly of N-docosyl pyridinium(TCNQ) Langmuir-Blodgett film at room temperature with the $NO_2$ gas-detection characteristics. As a result, we have found that their conductivities were increased by 6 times at 5 layers(about $250{\AA}$ thickness) LB film. However, their reproducibility was not able to be measured at room temperature. Therefore, we must find their working temperature which was able to activate gas-detection characteristics. The $NO_2$ gas response experiments under 200 ppm concentration in $50^{\circ}C$ show that :here are increment of electrical conductivity by 8 times and 100 seconds of response time, and 200 seconds of recovery times at $60^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.541_542
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• 2009

This paper reviews the definition and background of dynamic pricing which is the essential element of demand response system. Also, economic efficiency and related issues on dynamic pricing are studied. Several issues on design and operation of demand response system, which can implement the dynamic pricing, are described. Therefore the results will be helpful for developing the demand response system with dynamic pricing.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.48-49
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• 2006

Recently, Importance of Generator's Active/Reactive Power Control Capability is highly emphasized for prevention of Large Blackout. Especially, Generator's frequency Response Capability is important to the Power System Frequency Stability. This paper deals with the Development & Implementation of Each Generator Frequency Response Capability Test via the Injection of Artificial Frequency to the Online Generator. Actual On-line Generator's frequency Response Test was successfully implemented to 13 Generator having various fuel source.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.10-15
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• 2003

This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.666-668
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• 2002

Reluctance torque is generated by the rotor of the rugged construction in Synchronous Reluctance Motor. Its construction is simple, and it is very economic because a rotor in existed AC motor can be used. As the Synchronous inductance in Synchronous Reluctance Motor is an element that is proportional to torque, the exact value must be experimentally or analytically found for controlling and the performance development of motors. In this paper, direct torque control simulation to maximize the torque of the Synchronous Reluctance Motor and fast response characteristics was carried out with the inductance value by the Finite Element Method. For the simulation results, there are torques and fluxs response characteristics when controlling speed.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1707-1713
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• 2016

This paper proposes a dc error compensation algorithm using dq-synchronous coordinate transform digital phase-locked-loop in single-phase grid-connected converters. The dc errors are caused by analog to digital conversion and grid voltage during measurement. If the dc offset error is included in the phase-locked-loop system, it can cause distortion in the grid angle estimation with phase-locked-loop. Accordingly, recent study has dealt with the integral technique using the synchronous reference frame phase-locked-loop method. However, dynamic response is slow because it requires to monitor one period of grid voltage. In this paper, the dc offset error compensation algorithm of the improved response characteristic is proposed by using the synchronous reference frame phase-locked-loop. The simulation and the experimental results are presented to demonstrate the effectiveness of the proposed dc offset error compensation algorithm.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.674-682
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• 2017

This paper presents an optimal initial firing angle control based on the energy consumption and regenerative energy of a parallel multi-pulse thyristor dual converter for urban railway power substations. To prevent short circuiting the thyristor dual converter, a hysteresis band for maintaining a zero-current discontinuous section (ZCDS) is essential during mode changes. During conversion from the ZCDS to forward or reverse mode, the DC trolley voltage can be stabilized by selecting the optimal initial firing angle without an overshoot and slow response. However, the optimal initial firing angle is different depending on the line impedance of each converter. Therefore, the control algorithm for tracking the optimal initial firing angle is proposed to eliminate the overshoot and slow response of DC trolley voltage. Simulations and experiments show that the proposed algorithm yields the fastest DC voltage control performance in the transient state by tracking the optimal firing angle.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.3
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• pp.131-138
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• 1999

Generally, the digital controller has many advantages such as high precision, robustness to electrical noise, capability of flexible programming and fast response to the load variation. In this study, we have established proper mathematical equivalent model of Brushless DC (BLDC) motor and estimated the motor parameter by means of the back-emf measurement as being the step input to the controlled target BLDC motor. And the validity of proposed estimation method is confirmed by the test result of step response. As well, we have designed the reasonable digital controller as a consequence of the root locus method which is obtained from the open-loop transfer function of BLDC motor with hall sensor, and the determination of control gain for variable speed control. Here, revised Ziegler-Nichols tuning method is applied for the proper digital gain establishment, and the system stability is verified by the frequency domain analysis with Bode-plot and experimentation.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.123-125
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• 2004

This paper presents the application of response surface methodology (RSM) to design optimization for two types of synchronous reluctance motors (SynRMs); one has 12 slots with distributed winding, and the other has 6 slots with concentrated winding, to improve the ratio between torque ripple and average torque. The usefulness of RSM in optimization problem of SynRM is verified as compared with the results of finite element analysis. In the end, the optimized two SynRMs are compared with SynRM currently used in air-conditioning compressor in connection with torque performance and loss.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1727_1728
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• 2009

Nowadays DC-DC converter has been used widely in electronic production. It has a high requirement in wide input voltage, load variations, stability, providing a fast transient response and lower overshoot. However, it is not easy to be controlled because of its nonlinearity. In this paper, the nonlinear model of DC-DC converter is approximatedby four linear models and sub-controllers are designed by using the LMI guaranteeing the stability of the sub-systems at the same time. For the robust of the control system, an integral sliding mode control (ISMC) is applied together with LMI fuzzy controller. The proposed controller supports a fast and almost no overshooting transient response for the DC-DC converter control.