• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.139-142
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• 2002

A resonant type voltage source and power device and a control method using Pulse Density Modulation(PDM) power control and Pulse Width Modulation(PWM) voltage control for Ozone Generator are described. For the stability of discharge in the generating tube, it is desirable that the peak apply voltage is constant. The PDM power control is employed for sustaining the voltage constant at any generating tube input power. Moreover, to avoid the influence of input AC voltage fluctuation etc., PWM voltage control with generating tube peak voltage feedback is used. Both functions were confirmed by the experiment with 6.5[kHz], 1.8[kW] inverter and generating tube. The effect of input synchronous PDM method for input current stabilizing is confirmed also.

• Journal of Power Electronics
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• 제16권6호
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• pp.2016-2023
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• 2016

This paper presents a simple input-constrained current controller for a DC/DC boost converter with stability analysis that considers the nonlinearity of the converter model. The proposed controller is designed to satisfy the inherent input constraints of the converter under a physically reasonable assumption, which is the first contribution of this paper. The second contribution is providing a rigorous proof of the proposed control law, which keeps the closed-loop system along with the internal dynamics stable. The performance of the proposed controller is demonstrated through an experiment employing a 20-kW DC/DC boost converter.

• Journal of Power Electronics
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• 제16권3호
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• pp.925-935
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• 2016

This paper proposes a new interleaved double-input three-level Boost (DITLB) converter, which is composed of two boost converters indirectly in series. Thus, a high voltage gain, together with a low component stress and a small input current ripple due to the interleaved control scheme, is achieved. The operating principle of the DITLB converter under the individual supplying power (ISP) and simultaneous supplying power (SSP) mode is analyzed. In addition, closed-loop control strategies composed of a voltage-current loop and a voltage-balance loop, have been researched to make the converter operate steadily and to alleviate the neutral-point imbalance issue. Experimental results verify correctness and feasibility of the proposed topology and control strategies.

• 대한전기학회논문지
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• 제40권12호
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• pp.1230-1241
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• 1991

Asymmetrical pulse width modulated(APWM) control technique for AC chopper is proposed which can improve the input power factor. The ideal switching function for the proposed technique is derived and its optimal slope to maintain the input power factor to unity is calculated. By digital simulation several characteristics are investigated theoretically and then compared with those of the conventional PWM and the phase angle control technique. In order to maintain the input power factor to unity the optimal slope and the average value of the ideal switching function are calculated. The experimental results show a good agreement with the calculated ones, which proves the feasibility of the proposed technique.

• 대한전기학회논문지
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• 제45권1호
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• pp.30-41
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• 1996

Current Source(CS) PWM converter is appropriate for the magnet power supply system which requests high power and high precision current control. Input and output filters should be installed to eliminate the current or voltage harmonics caused by the PWM switching for the CS PWM converter. But the input/output filters limit the output DC current range and may destroy the system with filter resonance, and make the system equation more complicated. In this paper, systematic and simple filter design method which considers not only the harmonic attenuation but also the total system good transfer function characteristics in the dc filter. The simulated and experimental results verify the proposed theory. (author). refs., figs., tabs.

• Journal of Power Electronics
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• 제6권3호
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• pp.271-278
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• 2006

A new high efficiency zero-voltage and zero-current switching (ZVZCS) bidirectional DC/DC converter is proposed in this paper. The proposed converter consists of two symmetric half-bridge cells as the input and output stages. MOSFETs of input stage are turned-on in ZVS condition, and those of output stage are turned-off in ZCS condition. In addition, MOSFETs of input and output stages have low voltage stresses clamped to input and output voltage, respectively. Therefore, the proposed converter has high efficiency and high power density. The operational principles are analyzed and the advantages of the proposed converter are described. The 300W prototype of the proposed converter is implemented for 42V hybrid electric vehicle (HEV) application in order to verify the operational principles and advantages.

• 전기학회논문지
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• 제64권12호
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• pp.1810-1817
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• 2015

The railway vehicle has an auxiliary power unit for supplying power to the associated electronic control devices and passenger service unit. Typically, input voltage from the catenary for rolling stock is highly fluctuating according to the substation capacity, vehicle propulsion and regeneration. Especially, the frost and freezing on contact wire in winter can cause a blackout inside vehicle, and also brings about electronic components damaging and the system down. To prevent this problem, a large filter and capacitor is used. But this is not a perfect solution, because it is increasing weight of the unit. In this paper, a new algorithm is proposed to suppress the disturbance without adding devices. Simulation and experimental results show that the proposed algorithm has performance to suppress the disturbance at the sudden input voltage variations.

• Journal of Power Electronics
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• 제15권4호
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• pp.886-898
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• 2015

The design feasibility of a micro unidirectional DC transmission system based on an input-parallel output-parallel (IPOP) converter is analyzed in this paper. The system consists of two subsystems: an input-parallel output-series (IPOS) subsystem to step up the DC link voltage, and an input-series output-parallel (ISOP) subsystem to step down the output voltage. The two systems are connected through a transmission line. The challenge of the delay caused by the communication in the control system is addressed by introducing a ring communication structure, and its influence on the control system is analyzed to ensure the feasibility and required performance of the converter system under practical circumstances. Simulation and experiment results are presented to verify the effectiveness of the proposed design.

• 전력전자학회논문지
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• 제24권1호
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• pp.66-69
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• 2019

This study proposes a high-efficiency phase-shifted full-bridge (PSFB) converter with a wide input voltage range. The conventional PSFB converter is a useful topology in high-power applications. This converter not only achieves the zero-voltage switching of the primary switches, but also has small RMS current in the primary side. However, because the conventional PSFB converter has large freewheeling current in the primary side when it is designed considering the hold-up time of the converter, such a converter has high conduction loss at the primary switches. To solve this problem, a new PSFB converter is proposed in this study. The experiment is implemented with an input voltage ranging from a 320 V-400 V and an output power specification of 715 W.

• 전자공학회논문지
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• 제51권9호
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• pp.41-45
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• 2014

본 논문에서는 입력전력에 따라 드레인 바이어스를 조절하여 낮은 입력 전력에서도 고효율 동작이 가능한 무선전력전송용 고효율 class-E 전력증폭기를 설계하였다. 고효율 동작이 가능한 class-E 전력증폭기에 적응형 바이어스 조절회로를 추가하여 낮은 입력 전력에서 드레인 바이어스를 조절함으로써 전체적인 효율의 향상을 얻을 수 있다. 제안된 적응형 class-E 전력증폭기는 효율의 향상을 위해 직렬 공진회로와 입, 출력 정합회로를 이용하여 구현하였으며, 입력전력에 따라 드레인 바이어스를 조절하기 위해 방향성 결합기, 전력 검출기, 연산 증폭기를 이용하여 적응형 바이어스 조절회로를 구성하였다. 따라서 전력증폭기의 최대출력과 전력효율은 13.56 MHz에서 41.83 dBm, 85.67 %이고, 0 dBm ~ 6 dBm의 낮은 입력 전력에서 고정형 바이어스보다 평균 8 %의 효율의 증가를 확인하였다.