• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 추계학술대회
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• pp.157-158
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• 2011

This paper deals with the minimization of switching loss of a dual full-bridge bidirectional DC-DC converter for supercapacitor. In case of charging mode the switching loss can be minimized with proper switching pattern, and the switching loss in discharging mode can be minimized with soft switching. Simulation results show that the switching loss is reduced considerably.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.482-485
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• 1996

In this paper, a predictive current control of 12-pulse parallel connected dual converter system without interphase reactors(IPR) is presented. Firstly, the characteristics of system without IPR are analyzed and compared with that of system with IPR. And the predictive current control of this system is discussed. Finally the validity of the presented system and the excellence of the predictive current control response is proved through the simulation results.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.414-419
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• 1998

This paper describes the dynamical performance of a four-quadrant circulation current mode control of dc motor drive, using the controlled flywleeling technique, a four-quadrant closed-loop control drive with an inner current control loop and a speed fuzzy PI regulator is designed. The obtained computer simulation results of a dc motor drive below and above the base speed are demonstrated. These result show that compare to a conventional dual-converter-fed dc motor drive with simultaneous control, the overal system performance has been improved and also, agood stability and robstness has been achieved.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.327-328
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• 2014

This paper presents a pulse density modulation (PDM) technique with a high frequency link for a dual output DC-DC converter. The proposed scheme consists of a fixed frequency AC link and independent PDM controllers for the output regulation, which provides a simple structure and higher efficiency. The simulation and experimental results are provided to show the effectiveness of the proposed method.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.421-422
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• 2015

Nowadays, bidirectional DC-DC converters are becoming more into picture for different applications especially electric vehicles. There are many bidirectional DC-DC converters topologies; however, voltage-fed Dual Half-Bridge (DHB) topology has less number of switches as compared to other isolated bidirectional DC-DC converters. Furthermore, voltage fed DHB has galvanic isolation, high power density, reduced size, high efficiency and hence cost effective. Electrolytic capacitors always have problem regarding size and reliability in DC-AC single phase inverters. Therefore, voltage-fed DHB converter is proposed for the purpose of power decoupling to replace electrolytic capacitor by film capacitors. A new control strategy has been developed for 120Hz ripple rejection, and it was verified by simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1364-1367
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• 2005

In this paper, a novel prototype topology of soft switching PWM controlled high frequency AC power conversion circuit without DC voltage smoothing chemical capacitor filter link from the voltage grid of utility frequency AC power supply source with 60Hz-100V or 60Hz-200V is proposed and introduced for innovative consumer induction heating(IH) boiler applications as hot water producer, steamer and super heated vapor steamer.

• Journal of Power Electronics
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• 제15권3호
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• pp.577-586
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• 2015

The combination of voltage feedforward and feedback control is a conventional approach for correcting the power factor in single-phase ac-dc boost converters. The feedback duty ratio increases significantly with an increase of the line frequency and input inductance. Therefore, the performance of the conventional approach is highly dependent on the bandwidth of the feedback controller. As a result, the input power quality can be significantly exacerbated due to uncompensated duty ratios if the feedback controller is limited. This paper proposes an input impedance and current feedforward control method to reduce the control portion of the feedback controller. The findings in this paper are 1) the theoretical derivation and analysis of variations of line frequency and input inductance on a power factor correction approach, 2) guaranteed consistent performance in a wide range of conditions, and 3) that a low switching frequency can be utilized by the proposed method. A MATLAB/Simulink model and a 1.2kW dual boost converter are built to demonstrate the effectiveness of the proposed method.

• 센서학회지
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• 제14권5호
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• pp.350-356
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• 2005

We have developed a dual-channel type automatic measurement system to evaluate AC-DC current transfer difference of the thermal current converter(TCC) which is primary standard of AC current. The output drift effect of the TCC is minimized by measuring simultaneously the output voltages of two TCCs using voltmeter. Furthermore, the offset voltage of the voltmeter is cancelled nearly out by taking the average values of two outputs of TCCs measured with the forward-reverse directions using dual channel scanner. The uncertainties of the automatic system were 7 to $86{\mu}A/A$ for 3 mA to 10 A at 40 Hz to 20 kHz, which were evaluated by the comparisons between adjacent range of TCCs and inter-comparison with national measurement institute of Germany(PTB). The capability for ac-dc transfer difference measurement was improved by one order compared with that for the manual ac-dc measurement system.

• 정보처리학회논문지A
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• 제9A권1호
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• pp.93-98
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• 2002

본 논문에서는 하드디스크 드라이브 읽기 채널용 아날로그/디지털 변환기를 설계하였다. 본 회로는 고속 저에러율 비교 동작이 가능한 빠른 regenerative autozero 비교기에 기반을 두고 있고, 아키텍쳐에 Double Speed Dual ADC(DADA) 방식을 사용하여 전체 A/D 변환기의 속도를 효과적으로 향상시켰다. 또한 autozero 구조에 적합한 새로운 타입의 thermometer-to-binary 디코더를 사용하여 글리치를 제거하였고 기존의 구조를 보다 최적화시켰다. 이 ADC는 6-bit, 해상도, msample/s 최대 변환속도로 설계되었으며, 390mW 전력 소모와 한 클럭주기의 latency를 가진다. 설계에 0.65m CMOS 공정을 사용하였다.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.63-71
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• 2007

The conversion efficiency, durability and pressure drop of the automotive exhaust catalysts are dependent on the flow distribution within the substrate. Conventional porous medium approaches assuming monolith resistance based on the one-dimensional laminar flow for simulating the flow through the automotive exhaust catalysts over-predict the flow uniformity in the monolith. In this study, additional pressure loss is also considered by accounting for entrance effects due to the oblique flow incident on the front face of monolith as a consequence of flow separation and recirculation within the diffuser. The incorporation of an additional pressure loss improves the predictions for the maximum flow velocity within the substrate. An numerical study has also been conducted for the three-dimensional unsteady incompressible non-reacting flow inside various dual-monolith catalytic converters for the rapid acceleration/deceleration driving.