• The Transactions of the Korean Institute of Power Electronics
• /
• v.28 no.1
• /
• pp.68-75
• /
• 2023

This paper proposes a three-phase single-stage AC-DC converter for the small wind generation system. Input power factor improvement and insulated output can be implemented with the proposed three-phase single-stage AC-DC converter under the wide power generation voltage (80-260 V_ac) and frequency (10-42 Hz) in a small wind power generation (WPG) system. The proposed converter is also capable of zero-voltage switching in the primary-side switches and zero-current switching in the secondary-side diodes by phase-shift control at a fixed switching frequency. In addition, it is possible to control a wide output voltage (V_o: 39 V_DC-60 V_DC) by varying the link voltage and improving the input power factor (PF) and the total harmonic distortion factor (THD_i). Simulation and experimental results verified the validity of the proposed converter.

• The Journal of the Acoustical Society of Korea
• /
• v.25 no.2
• /
• pp.61-71
• /
• 2006

An MP3 encoder chip has been designed and fabricated with the hardware and software co-design concepts. In the aspect of the software. the calculation cycles of the distortion control loop. which requires most of the calculation cycles in MP3 encoding procedure. have been reduced to $67\%$ of the original algorithm through the 'scale factor Pre-calculation'. By using a floating Point 32 bit DSP core and designing the FFT block with the hardware. we can get the additional reduction of the calculation cycles in addition to the software optimization. The designed chip has been verified using HW emulation and fabricated via 0.25um CMOS technology The fabricated chip has the size of $6.2{\time}6.2mm^2$ and operates normally on the test board in the qualitative and quantitative aspect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.05c
• /
• pp.53-56
• /
• 2004

This paper describes the method of position error reduction in Linear Pulse Motor (LPM). Though the micro step exiting method is applied, the vibration and position error caused by trust distortion from mechanism still remains. This paper presents the method for reduction of position error on moving the mover at whole cycle, by compensating a scale factor through real-time control of the PWM pulse width corresponding to exiting current command and absolute position error from linear encoder.

• Journal of Industrial Technology
• /
• v.19
• /
• pp.217-226
• /
• 1999

A single phase to three phase power converter with cost effective and simple structure is proposed. The converter consists of rectifier and inverter. The rectifier is composed of a half wave rectifier, a dc link capacitor, and a current limiting inductor, and the inverter is of only two switches with PWM control. For negative sequence operation the inverter output voltage leads the line input by $60^{\circ}$, and for positive sequence operation the inverter output voltage leads by $60^{\circ}$. We can see that positive sequence operation shows higher output voltage, slight harmonic distortion(2%), and better performances such as high efficiency and high power factor. A mathematical model for system analysis is provided, and specifications for selection and control scheme both for start-up and for steady state are analyzed. comparison and operational limits of positive and negative sequence operation are performed, and simulations and experiments are executed to verify the proposed.

• Journal of Power Electronics
• /
• v.12 no.5
• /
• pp.689-698
• /
• 2012

This paper investigates the effects of applying different input current waveshapes on the performance of a continuous-conduction-mode (CCM) power-factor-correction (PFC) boost pre-regulator. It is found that the output voltage ripple of the pre-regulator can be reduced if the input current is modified to include controlled amount of higher order harmonics. This finding allows us to balance the performance of output regulation and the harmonic current emission when coming to the design of the pre-regulator. An experimental PFC boost pre-regulator prototype is constructed to verify the analysis and show the benefit of the pre-regulator operating with input current containing higher order harmonics.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.600-608
• /
• 2013

This paper analyzes the effect of the admittance component for the digitally controlled single-phase bridgeless power factor correction (PFC) converter. To do this, it is shown how the digital delay effects such as the digital pulse-width modulation (DPWM) and the computation delays restrict the bandwidth of the converter. After that, the admittance effect of the entire digital control system is analyzed when the bridgeless PFC converter which has the limited bandwidth is connected to the grid. From this, the waveform distortion of the input current is explained and the compensation method for the admittance component is suggested to improve the quality of the input current. Both the simulations and the experiments are performed to verify the analyses taken in this paper for the 1 kW bridgeless PFC converter prototype.

• Journal of Power Electronics
• /
• v.12 no.2
• /
• pp.258-267
• /
• 2012

An interleaved single-stage AC/DC converter with a boost converter and an asymmetrical half-bridge topology is presented to achieve power factor correction, zero voltage switching (ZVS) and load voltage regulation. Asymmetric pulse-width modulation (PWM) is adopted to achieve ZVS turn-on for all of the switches and to increase circuit efficiency. Two ZVS half-bridge converters with interleaved PWM are connected in parallel to reduce the ripple current at input and output sides, to control the output voltage at a desired value and to achieve load current sharing. A center-tapped rectifier is adopted at the secondary side of the transformers to achieve full-wave rectification. The boost converter is operated in discontinuous conduction mode (DCM) to automatically draw a sinusoidal line current from an AC source with a high power factor and a low current distortion. Finally, a 240W converter with the proposed topology has been implemented to verify the performance and feasibility of the proposed converter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.3
• /
• pp.180-191
• /
• 2022

In this paper, a single-stage alternating current (AC)-DC converter is proposed for the automated-guided vehicle wireless charging system. The proposed converter is capable of soft-switching under all input voltage (VAC: 220 Vrms ± 10%), load conditions (0-1 kW), and air gap changes (40-60 mm) by phase control at a fixed switching frequency. In addition, controlling a wide output voltage (Vo: 39~54 VDC) is possible by varying the link voltage and improving the input power factor and the total harmonic distortion factor. Experimental results were verified by making a prototype of a 1-kW wireless power charging system that operates with robustness to changes in air gaps.

• Proceedings of the KIPE Conference
• /
• 2001.12a
• /
• pp.119-123
• /
• 2001

In this paper, a DCM operated boost integrated single-stage forward-flyback converter is proposed. This proposed converter has high power factor, low harmonic distortion, and tight output regulation. To increase efficiency, zero voltage switching with asymmetrical control is used. This converter also give low voltage stress in switch and this results in low conduction loss with low turn-on resistance.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.2 no.1
• /
• pp.33-38
• /
• 1997

Generally, various semiconductor switching devices for power systems are used in battery chargers for electric vehicle. When these used, it takes the problems of transient-current or distortion of waveforms in power systems near by battery chargers because of harmonics and large peak-current, low power factor, etc., caused by the non-linearity of these devices. Recently, power factor control, line current peak-cut, harmonics reduction which was ignored in past is more and more important. In this paper, to solve those problems we will improve the characteristics of voltage rising and propose the high power factor converter circuit for battery chargers. Our proposed system convert commutated voltage to AC resonant wave in high frequency inverter and rectify the link voltages passed high-frequency transformer and transfer the DC voltages. Especially, the effect using these converter system can be improved very large by power factor control and we have to verify the possibilities of improvement through the experiment of Pb-Acid battery application.