• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.85-91
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• 2008

A Boost Power Factor Correction (PFC) Converter employing Zero Voltage Switching (ZVS) based Compound Active Clamping (CAC) technique is presented in this paper. An Electro Magnetic Interference (EMI) Filer is connected at the line side of the proposed converter to suppress Electro Magnetic Interference. The proposed converter can effectively reduce the losses caused by diode reverse recovery. Both the main switch and the auxiliary switch can achieve soft switching i.e. ZVS under certain condition. The parasitic oscillation caused by the parasitic capacitance of the boost diode is eliminated. The voltage on the main switch, the auxiliary switch and the boost diode are clamped. The principle of operation, design and simulation results are presented here. A prototype of the proposed converter is built and tested for low input voltage i.e. 15V AC supply and the experimental results are obtained. The power factor at the line side of the converter and the converter efficiency are improved using the proposed technique.

• Journal of KSNVE
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• v.6 no.2
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• pp.205-214
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• 1996

Active noise control(ANC) requires the full capability of a modern digital signal processing module. This paper describes the digital signal processing unit which is designed for ANC of noise fields in passenger car. System hardware is designed to allow software controlled versatility as well as fully qutomatic operation. The developed system is provided with the ability to be self-operated except the case of upload/download of data and program between the personal computer and the system memory. Experimental results are presented to demonstrate ANC performance of noise fields in lightly damped enclosure and passenger car.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1204-1209
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• 2000

Many analytical and experimental studies on the active suppression of nonlinear panel flutter by using piezoceramic patch have been carried out. However, these active control methods have a few important problems; a large amount of power is required to operate actuators, and additional apparatuses such as sensor systems and controller are needed. In this study passive suppression schemes for nonlinear flutter of composite panel, which is believed to be more robust suppression system than active control in practical operation, are proposed by using piezoelectric inductor-resistor series shunt circuit. Toward the end, a finite element equation of motion for an electromechanically coupled system is proposed using the Hamilton's principle. To achieve the best damping effect, optimal shape and location of the piezoceramic(PZT) patches are determined by using genetic algorithms. The results clearly demonstrate that the passive damping scheme by using piezoelectric shunt circuit can effectively attenuate the flutter.

• Journal of Industrial Technology
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• v.34
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• pp.71-78
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• 2014

Recently, using the electronic devices was increased with semiconductor developments. So, the EMI(Electromagnetic interference) problem become to important issue for coexistence with each electronic devices. The EMI is caused by switching operation from the power switches as the FET and the transistor in power conversion devices. In this paper, the hybrid EMI filter that composed with active components and passive components was described. The EMI filter is applied to the 160 watts LED driver experimentally verify the performance. The hybrid EMI filter is compared with non-filter, only passive filter and only active filter. The proposed EMI filter attenuated CM noise more than traditional passive filter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.214-220
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• 2008

Most of converter system could obtain almost unity power factor and make input current sinusoidal waveform, but they have many problems, such as electromagnetic interference and switching losses caused by switching noise in main switch. To solve these problems in hard switching PFC converter, soft switching converter using a resonant between capacitor and inductor is invented In this paper, advantages and disadvantages of conventional ZVT(Zero-Voltage-Transition) soft switching converter using a auxiliary resonant circuit is discussed. Then Improved ZVT soft switching converter proposed. This improved ZVT converter's operation principal, specific property, design scheme of main are described. From Simulation and experiment results of conventional ZVT soft switching and improved ZVT soft switching converter with active snubber, characteristics of the converter are confirmed.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.142-143
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• 2010

An active-clamped current-fed half-bridge converter for the high step-up application is proposed in this paper. The proposed converter is composed of active clamping snubber circuits and a voltage doubler rectifier. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, features, and validity of the proposed circuit, the experimental result for a 200W, 24V input and 400V output prototype are presented.

• Journal of Power Electronics
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• v.8 no.4
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• pp.317-324
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• 2008

This paper proposes a Multiband Shunt Hybrid Active Filter (SHAF) with sensorless control. A plant is modeled in the discrete- time domain and a controller is designed using the Pole shifting law in the polynomial domain. This control approach is very useful for filtering the load harmonics with reduced sensor counts where a low cost solution like SHAF is required. Multiple Synchronous Reference Frames (MSRF) and low pass filters are used to measure the $5^{th}$ and $7^{th}$ harmonic components separately from the load and filter currents. Individual current controllers are designed for the $5^{th}$ and $7^{th}$ harmonic currents. Control is realized in the stationary, three-phase (abc) reference frame. Performance of the controller is validated through simulation, using realistic plant and controller models, as well as experimentally on a full-scale distribution system.

• Journal of Power Electronics
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• v.13 no.4
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• pp.692-700
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• 2013

This paper discusses the design of a novel synchronous reference frame (SRF) method that can extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous SRF studies, the proposed method has an innovative feature that does not require a fictitious current signal. Other key features of the proposed strategy include frequency-independent operation, accurate reference current extraction, and relatively fast transient response. The effectiveness of the proposed method is investigated by conducting a detailed mathematical analysis. Results of the analysis confirm the superior performance of the suggested approach. Theoretical evaluations are confirmed by the experimental results.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.82-87
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• 2002

For the dynamic behavior evaluation of a semi-active vibration control system, it is very important to use an accurate mathematical model for the hydraulic damper applied to the control system. In this study, a mathematical model for a symmetric type hydraulic damper was suggested. In this model, the effects of gas volume and oil temperature variation on the bulk modulus of oil were considered. The dynamic behavior of the damper was investigated by experiments and simulations. It was confirmed that the pressure variation, damping force, and mean pressure variation could be estimated with comparatively good precision by the suggested mathematical model. Moreover, it was shown that excessive pressure rise can be generated by the oil expansion due to the heat energy transformed from the exciting energy of the damper for a short period of the damper operation.

• The Journal of Korea Robotics Society
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• v.8 no.2
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• pp.75-81
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• 2013

This research would investigate deeply the operation of an omni-directional mobile robot that is able to move with high acceleration. For the high acceleration performance, the vehicle utilizes the structure of Active Split Offset Casters (ASOCs). This paper is mainly focused on inverse kinematics of the structure, hardware design to secure durability and preserve the wheels' contact to the ground during high acceleration, and localization for the real time position control.