• Journal of Power Electronics
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• v.19 no.4
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• pp.881-893
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• 2019

This paper proposes a practical sliding-mode controller design for shaping the impedances of cascaded boost-converter power decoupling circuits for reducing the second order harmonic ripple in photovoltaic (PV) current. The cascaded double-boost converter, when used as power decoupling circuit, has some advantages in terms of a high step-up voltage-ratio, a small number of switches and a better efficiency when compared to conventional topologies. From these features, it can be seen that this topology is suitable for residential (PV) rooftop systems. However, a robust controller design capable of rejecting double frequency inverter ripple from passing to the (PV) source is a challenge. The design constraints are related to the principle of the impedance-shaping technique to maximize the output impedance of the input-side boost converter, to block the double frequency PV current ripple component, and to prevent it from passing to the source without degrading the system dynamic responses. The design has a small recovery time in the presence of transients with a low overshoot or undershoot. Moreover, the proposed controller ensures that the ripple component swings freely within a voltage-gap between the (PV) and the DC-link voltages by the small capacitance of the auxiliary DC-link for electrolytic-capacitor elimination. The second boost controls the main DC-link voltage tightly within a satisfactory ripple range. The inverter controller performs maximum power point tracking (MPPT) for the input voltage source using ripple correlation control (RCC). The robustness of the proposed control was verified by varying system parameters under different load conditions. Finally, the proposed controller was verified by simulation and experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.303-309
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• 2013

A low power 6-bit flash ADC that uses an input voltage range detection algorithm is described. An input voltage level detector circuit has been designed to overcome the disadvantages of the flash ADC which consume most of the dynamic power dissipation due to comparators array. In this work, four digital input voltage range detectors are employed and each input voltage range detector generates the specific clock signal only if the input voltage falls between two adjacent reference voltages applied to the detector. The specific clock signal generated by the detector is applied to turn the corresponding latched comparators on and the rest of the comparators off. This ADC consumes 68.82mW with a single power supply of 1.2V and achieves 4.9 effective number of bits for input frequency up to 1MHz at 500 MS/s. Therefore it results in 4.75pJ/step of Figure of Merit (FoM). The chip is fabricated in 0.13-um CMOS process.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.62-70
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• 2007

In this paper, the boost Power Factor Correction(PFC) technique for Direct Torque Control(DTC) of brushless DC motor drive in the constant torque region is implemented on a TMS320F2812DSP. Unlike conventional six-step PWM current control, by properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained, therefore a much faster torque response is achieved compared to conventional current control. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, a pre-stored back-EMF versus position look-up table is designed. The duty cycle of the boost converter is determined by a control algorithm based on the input voltage, output voltage which is the dc-link of the BLDC motor drive, and inductor current using average current control method with input voltage feed-forward compensation during each sampling period of the drive system. With the emergence of high-speed digital signal processors(DSPs), both PFC and simple DTC algorithms can be executed during a single sampling period of the BLDC motor drive. In the proposed method, since no PWM algorithm is required for DTC or BLDC motor drive, only one PWM output for the boost converter with 80 kHz switching frequency is used in a TMS320F2812 DSP. The validity and effectiveness of the proposed DTC of BLDC motor drive scheme with PFC are verified through the experimental results. The test results verify that the proposed PFC for DTC of BLDC motor drive improves power factor considerably from 0.77 to as close as 0.9997 with and without load conditions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.75-81
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• 2015

At the end of the 19th century, Edison's DC power system and Tesla's AC power system was debated in power market. Finally, AC system became the primary system of the power market because both step-up and step-down of voltage by using transformer and long-distance power transmission are easily possible. However, nowadays the power market takes some action for introducing DC system. Both domestic and foreign researchers are conducting the study on the DC system as well. Some researchers have conducted the studies on power quality and economic evaluation of the DC distribution system but DC distribution system is still controversial in terms of the effectiveness and reliability. In this paper, we calculate the reliability indices of the Low Voltage Direct Current(LVDC) distribution system considering arrangement of power electronics, layout of the distribution system, and distance between load points.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.25-29
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• 2017

This paper presents a hetero-integration of electrostatically actuated RF MEMS Switch and step up DC-DC converter on a redistribution layer using commercial PCB process. RF characteristics of Duroid with $56{\Omega}$ impedance GCPW transmission line and that of FR4 with $59{\Omega}$ impedance CPW transmission line were analyzed. From DC to 6GHz, RF characteristics of Duroid were better than that of FR4, insertion loss was 2.08dB lower, return loss was 3.91dB higher, and isolation was 3.33dB higher.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.600-602
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• 1996

The purpose of this paper is to develop a new maximum power point tracking(MPPT) using fuzzy set theory for air conditioning system. Fuzzy algorithm based on linguistic rules describing the operator's control strategy is applied to control step-up chopper for MPPT. Fuzzy algorithm is applied to control boost MPPT converter by temperature compensation effect with 8 bit single chip 8051 microcontroller. In this paper, temperature compensation(Becom Transducer : pf-T type) range is $-40^{\circ}C{\sim}+100^{\circ}C$.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.504-507
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• 1991

Modelling and simulation of booster which is used as step-up DC/DC converter for small scale fuel cell generator is studied. And 2kW booster based on this result is designed. Especially, booster efficiency related with fuel cell and control characteristics are analyzed and a 2kW booster is experimented in various operating condition. As a result, power conversion efficiency is above 74% throughout the whole operating range.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.334-335
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• 2011

본 논문에서는 절연이 요구되지 않는 고승압 응용에 적합한 비절연 고승압 컨버터를 제안한다. 제안하는 컨버터는 기존의 부스트 컨버터에 비해 약 2배의 승압비를 가지며 스위치와 다이오드의 전압 정격이 1/2로 감소되어 RDS(ON)이 작은 소자를 선정할 수 있다. 또한 스위치의 ZVS 턴온과 ZCS 턴오프가 성취되며 보조 회로의 공진을 이용함으로서 기존 방식에 비해 스위치의 턴오프 전류가 낮아져 스위칭 손실이 감소한다. 2kW의 시작품을 제작하여 제안하는 컨버터의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.72-73
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• 2011

본 논문에서는 공진형 액티브 클램핑 플라이백 회로를 구성하여 전력스위칭의 전압 클램핑을 통하여 스위칭 손실을 저감하고자 하였다. 또한, 입력측 대용량 인덕터를 대신하여 공진형 액티브 클램핑 플라이백 회로에 두 개의 변압기를 사용하여 효율개선 및 고승압을 구현하고자 하였으며, 하드웨어 Prototype을 제작하여 타당성을 검증하였다.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1038-1040
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• 1992

Booster is used widely as one of the step-up DC/DC power converter in power conversion process for fuel cell power plant which have the electrical characteristic of the high current density and low cell voltage. In view of control system, booster can be unstable when it is operated in broad operation range because the transfer function of booster has zero in right half plane of s-domain. So for reliable operation, controller must make the system stable in whole working range. In this paper, the two control method such as digital PID control and fuzzy control is studied for booster output voltage regulation in fuel cell plant. The design procedure of PID control and fuzzy control is described. And the experiment of designed controller action is performed in various operation points for controller performance test.