• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.345-351
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• 2000

To improve the current waveform of diode rectifiers, we propose a new operating principle of the voltage diode rectifiers. In the conventional voltage rectifier circuit, relatively large capacitors are used to boost the output voltage, while the proposed circuit uses ones and a small reactor not boost the output voltage but improve the input current waveform. A circuit design method is shown and confirmed simulation. It explained that compared conventional PWM(Pulse-width modulated)inverter with HPWM(Half Pulse-width modulated)inverter. Proposed HPWM inverter eliminated dead-time by lowering switching loss and holding over-shooting. Output voltage and current of this paper were applied for real air-conditioner.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.596-607
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• 2006

This paper presents Single Phase Switched Reluctance Motor (SPSRM) optimum design for vacuum cleaners using Response Surface Methodology (RSM) to determine geometric parameters, and the 2-D Finite Element Method (FEM) has been coupled with the circuit equations of the driving converter. Additionally, an optimum process for SPSRM has been proposed and peformed with geometric and electric parameters thereby influencing the inductance variation and effective torque generation as design variables. SPSRM performances have also been analyzed to determine an optimal design model for maximized efficiency at high power factor. In order to confirm the propriety of the Finite Element Method and motor performance calculation, simulation waveform and experiment waveform for motor voltage and current were compared.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.7-11
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• 1989

A Faraday rotator is designed with the HOYA FR-5 rotator glass. We find that traveling light rotates 45$^{\circ}$in the glass when magnetic field intensity is about 3.0$\times$105AT/m. The current of 2.7KA flowing in the coil of the 0cm diameter, 29cm long and 41 windings generates this magnetic field. A pulse forming network is designed for this current of 84 sec duration. The network is analyzed numerically to find the relevant circuit parameters for the flattest current waveform.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.219-225
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• 2014

This paper describes an IC for Power Factor Correction. It can use electrical appliances which convert power from AC to DC. The power factor can be influenced not only phase difference of voltage and current but also sudden change of current waveform. This circuit enables current wave supplied to load by close to sinusoidal and minimum phase difference of voltage and current waveform. A self oscillated 10[kHz]~100[kHz] pulse signal converted to PWM waveform and it chops rectified full wave AC power which flows to load device. The multiplier and zero current detector circuit, UVLO, OVP, BGR circuits were designed. This IC has been designed and whole chip simulation use 0.5[um] double poly, double metal 20[V] CMOS process.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2126-2128
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• 1997

In order to establish the robust current controller design technique of series wound motor driver system. This paper proposes a method of compensated Bang-Bang current control using a series wound motor driver system under improperly variable load. Real time implementation of compensated Bang-Bang current controller achieved. Concept design strategy of the control and PWM waveform generation algorithms are presented in the paper.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.2
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• pp.157-163
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• 2014

This paper proposes a two-stage step-down buck and a tapped-inductor boost cascaded converter for high efficiency photovoltaic micro-inverter applications. The proposed inverter is a new structure to inject a rectified sinusoidal current into a low-frequency switching inverter for single-phase grid with unity power factor. To build a rectified-waveform of the output current. the converter employs both of a high efficiency step-up and a step-down converter in cascade. In step-down mode, tapped inductor(TI) boost converter stops and the buck converter operates alone. In boost mode, the TI converter operates with the halt of buck operation. The converter provides a rectified current to low frequency inverter, then the inverter converts the current into a unity power-factor sinusoidal waveform. By applying a TI, the converter can decrease the turn-on ratios of the main switch in TI boost converter even with an extreme step-up operation. The performance validation of the proposed design is confirmed by an experimental results of a 120W hardware prototype.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1121-1133
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• 1998

In this paper, a new method is proposed for a simple andaccurate design of larage-sigal power amplifier using the output current- and volage- waveform analysis. An existing high-efficiency theory, Harmonic Loading, is modified to apply to a real device, and the notion of "actual bias point at large-signal input" is proposed. Based on the proposed theory, 2GHz band poweramplifier is implemented using HEMT device, and the implemented amplifier shows 14dBm output power, 46% drain efficienty, 38% power-added efficiency and 7.8dB gain at 2V bias voltage.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.162-166
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• 2008

This paper presents the design and implementation of a 5kW programmable three-phase harmonic generator, which is capable of generating sinusoidal output voltages with adjustable output amplitude and frequency over a wide range as well as arbitrary waveforms. The considered harmonic generator is a linear power amplifier type. This system consists mainly of a power converter to generate and amplify waveform signals, a controller to control the desired output signal and measure the output parameters including voltage and current, and a control program to set the desired output and display the output values. The prototype programmable three-phase harmonic generator has been constructed and tested. Test results show that the developed programmable three-phase harmonic generator performs well.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.5
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• pp.71-85
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• 1993

The Cycloconverter that the author is going to treat in this paper, has strong advantages over the D.C. Link Inverter in points of chattering torque problem and natural commutation. Thus, the Cycloconverter is expected to be well applied to large and low-speed machines which require better speed control at low frequency. But the control circuit of Cycloconverter has two weak points described as follows. 1) Because of its rather complicated control circuit, it is likely to be illoperating due to unexpected noise signals, thus the higher the accuracy and reliability of the circuit is required to be, the more the circuit may cost. 2) Because the load current is not purely sinusoidal, the Cycloconverter may possibly be destroyed in case of inaccurate convert switching resulted from the difficulties in detecting the load current-zero and the current direction at the moment. In this paper, the author first of all intends to design and build a modified VVVF-type Noncirculating Current Cycloconverter to which recently proposed control methods are applied for improving the circuit simplicity, the control performance, and the system reliability. And then, experiments for observing the output waveforms of the Cycloconverter which is controlled by Singled-Board Computer using 8086 16-bit microprocesser are carried out. Finally the author concludes the result of this study as follows. 1) By replacing the conventional analog control circuits such as Reference Wave Generator, Cosine Timing Wave Generator, and Comparator with softwares, a great circuit simplicity is achieved. 2) The output of the designed Cycloconverter changes its frequency very fast without showing discontinuity of its waveform, and this waveform characteristics enables the smooth speed control of Induction Motor. 3) The design control circuit of Cycloconverter can be applied to the systems of 12 or 24 pulses because of its short processing period.

• Journal of Sensor Science and Technology
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• v.6 no.3
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• pp.245-251
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• 1997

In designing defibrillator, several parameters such as patient's transthoracic impedance, output energy level, peak current, and time duration of current waveform must be considered to generate optimum electrical shocks on the heart. Patient's transthoracic impendence depends on the physical and health condition of patient. In this study, before the development of a defibrillator, the range of above parameters value as circuit elements was determined to derive optimal waveform by predicting and analyzing the performance of designed circuit by means of simulation with the software, P-Spice. The efficiency of parameter design was verified through the performance test with the developed defibrillator.