• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.237-240
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• 2000

A new control method using average comparison strategy have been proposed in this paper. This control method realizes sinusoidal input and output current. unity input displacement factor regardless of load power factor. Moreover compensation of the asymmetrical and harmonic containing input voltage is sautomatically realized and calculation time of control function is reduced.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.236-240
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• 2014

Induction motor requires a rotating magnetic for rotation. Current required to generate the rotating magnetic field is magnetizing current. This magnetizing current is associated with the reactive power. This reactive power must be supplied from source side. Therefore, the power factor of the induction motor is low. So, the capacitor is installed on the motor terminals to compensate for the low power factor. Power supply company has recommended to maintain a high power factor to the customer. If the capacitor current is greater than the magnetizing current of the motor, there is a possibility that the self-excitation occurs. So it is necessary to calculate the optimal capacity capacitor current does not exceed the magnetizing current. In this study, we first compute the no-load current and the reactive power of the induction motor and then calculates the limit of the maximum power factor without causing self-excitation.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.413-416
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• 1997

In this paper, we propose a new single-stage isolated switching power supply. The proposed converter reduces the diode conduction loss and offer both the high input Power factor and the direction conversion from the ac line to a dc output voltage. This paper present the Operational principle, analysis and control and experimental results of a 100W prototype.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.242-243
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• 2012

In this paper, 200 W power supply for LED driver has been designed, analyzed, simulated and tested. Input AC voltage of 100VAC-240VAC was converted to DC voltage by high power factor converter. Output voltage was controlled, and output current was controlled by constant current when output current was reached to LED maximum rated current. By simulation and experimental test, voltage and current control and high power factor characteristics are verified.

• Journal of KSNVE
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• v.11 no.2
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• pp.257-264
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• 2001

In this research, piezoelectric smart structures are applied for SEA(Statistical Energy Analysis), which is well known approach for high frequency analysis. A new input power measurement based on piezoelectric electrical power measurement is proposed and compared with the conventional method in SEA. As an example, a simple aluminum beam on which piezoelectric actuator is attached is considered. By measuring the electrical impedance and electrical current of the piezoelectric actuator, the electrical power given on the actuator is found and this is In turn converted into the mechanical energy. From the measured value of the stored energy of the beam, the Internal loss factor is calculated and this value shows a good agreement with that given by the conventional method as well as the theoretical value. To compare the coupling loss factor, L-shape beam system which consists of a aluminum beam subsystem and a steel beam subsystem coupled by three pin is taken as second example. The input power and stored energy of each subsystem are found by the proposed approach. The coupling loss factor found by the electrical input power obtained from the piezoelectric actuator exhibits similar trend to the value found by the conventional method as well as the theoretical value. In conclusion, the use of SEA for high frequency application of piezoelectric smart structures is Possible. Especially, the input power that is essential for SEA can be found accurately by measuring the electrical input power of the piezoelectric actuator.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.920-927
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• 1998

This paper proposed that an Analysis of a partial resonant AC-DC converter for high power and power factor operates with four choppers connecting to a number of parallel circuit. To improve these, a large number of soft switching topologies included a resonant circuit have been proposed. And, some simulative results on computer are included to confirm the validity of the analytical results. The partial resonant circuit makes use of an inductor using step-down and a condenser of lose-less snubber. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in a partial resonant circuit makes charging energy regenerated at input power source for resonant operation. The proposed conversion system is deemed the most suitable for high power applications where the power switching devices are used

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.8
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• pp.392-401
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• 2001

This paper presents the single-stage high power factor AC to DC converter operated in active-clamp mode. The proposed converter is added active-clamping circuit to boost-flyback single-stage power factor corrected power supply. The active-clamping circuit limits voltage spikes, recycles the energy trapped in the leakage inductance, and provides a mechanism for achieving soft switching of the electronic switches to reduce the switching loss. The auxiliary switch of active-clamping circuit uses the same control and driver circuit as the main switch to reduce the additional cost and size. To verify the performance of the proposed converter, a 100W converter has been designed. The proposed converter gives good power factor correction, low line current harmonic distortions, and tight output voltage regulation, as used unity power factor.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1211-1213
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• 2003

A pulse width modulation(PWM) method for single-phase Sepic-type rectifier is introduced in this paper. The characteristics of the proposed PWM system are high performance high power factor with low input current harmonic distortion. The proposed control method is based on the average-current-mode using the dedicated integrated circuit UC3854 this technique it is possible to implement a very simple control circuit for unitary power-factor in CCM operation and also to provide over-current protection.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.219-223
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• 2017

In this paper, we calculated the losses in the high voltage lines of power distribution system. The losses caused by high voltage lines are calculated using maximum current, resistance, loss factor, and dispersion loss factor. The accurate extraction of these factors are very important to calculate the losses exactly. Thus, the maximum loads are subdivided to regions and calculated monthly for more accurate maximum current calculation. Also, the composite resistance is calculated according to the ratio of the used wire types. In order to calculate the loss factor, the load factors according to the characteristics of each region were calculated. Finally, the losses of the distribution system is calculated by adding the losses by the transformers and the low voltage lines.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.746-749
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• 2002

This paper presents a new control method for the high frequency electronic ballast which is operated with raw rectified dc link using diode bridge. For the commercial electronic ballast, proper ac input power factor and crest factor of the lamp current are required. The most ballast, therefore, has a active or passive power factor collection (PFC) circuit. With the proposed method, it can be achieved simultaneously that grater than 0.9 of input power factor and less than 1.85 of lamp current crest factor without any PFC circuit. In this paper, the proposed ballast control scheme and the experimental results for the application to the fluorescent lamp are described.