• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.248-249
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• 2010

This paper deals with the design and experiment of 85kW(17kV, 5A) high voltage power supply for 60kW industrial magnetron. The power supply was designed based on the series resonant converter discontinuous conduction mode(DCM) which has the current source characteristic and high efficiency. In addition, inevitable leakage inductance of high voltage transformer can be used as resonant inductance. The basic analysis of full-bridge series resonant converter with transformer is given and the relationships between resonant tank parameters and input, output specification was derived. Simulation and experiment was done with variable switching frequency and their results verify the theoretical analysis.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.520-527
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• 2016

A new dual-loop digital delay-locked loop (DLL) using a hybrid (binary + sequential) search algorithm is presented to achieve both wide-range operation and high delay resolution. A new phase-interpolation range selector (PIRS) and a variable successive approximation register (VSAR) algorithm are adopted to resolve the boundary switching and harmonic locking problems of conventional digital DLLs. The proposed digital DLL, implemented in a $0.18-{\mu}m$ CMOS process, occupies an active area of $0.19mm^2$ and operates over a wide frequency range of 0.15-1.5 GHz. The DLL dissipates a power of 11.3 mW from a 1.8 V supply at 1 GHz. The measured peak-to-peak output clock jitter is 24 ps (effective pk-pk jitter = 16.5 ps) with an input clock jitter of 7.5 ps at 1.5 GHz. The delay resolution is only 2.2 ps.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.173-174
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• 2015

본 논문에서는 가변 스위칭 주파수를 이용하여 단일스위치 이중출력 플라이백 컨버터의 전압조정특성을 향상시키는 방법을 제안한다. 기존의 이중 출력 컨버터에서는 부하의 변화, 누설 인덕턴스나 자화 인덕턴스의 영향 때문에 두 개의 출력전압을 개별적으로 제어하기가 힘들다. 제안된 방법에서는 컨버터의 2차측에 조정된 필터를 추가함으로써, 스위칭 소자의 듀티비가 일정하더라도 스위칭주파수에 따라 다른 전압을 출력하도록 하였다. 따라서 듀티비 제어뿐 아니라 스위칭 주파수 제어로도 출력전압을 제어할 수 있기 때문에 어떠한 상황에서도 각각의 출력을 제어하는 것이 가능하다. 추가적인 능동소자 없이 필터만을 추가 하여 기존 플라이백 컨버터의 특징인 간결한 제어알고리즘과 회로구성을 유지하였다. 또한 프로토 타입의 이중출력 컨버터를 이용하여 제안된 방법의 성능 및 구현 가능성을 검증하였다.

• 전력전자학회논문지
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• 제25권2호
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• pp.142-151
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• 2020

This paper presents a DC/DC LLC resonant converter with wide input/output voltage gain characteristics and its control method for efficiency improvement. For a wide input/output voltage gain characteristics without designing small transformer magnetization inductance, the proposed converter changes the topology into three modes of operation according to the main switch switching pattern. In each operating mode, variable LINK voltage modulation and frequency modulation were performed to control output voltage and improve operating efficiency. A prototype of a 5-kW DC/DC LLC resonant converter was built and tested to verify the validity and applicability of the proposed converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.147-149
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• 1994

Binary control with integral COFB is presented to alleviate the chattering. Binary control system consists of the main loop and the external loop which transforms the gain of main loop smoothly, and can generate the continuous control input under the existence of the delay and the switching frequency limitation of the controller. Therefore, it has the properties of chattering alleviation, in addition, advantages of the conventional variable structure control. To confirm the validity of the developed controller, position control of brushless DC motor with binary controller as a position controller is performed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.174-176
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• 1995

An additional consideration for using general Induction Motor are about copper loss by harmonic component of source, and increase of iron loss due to switching frequency in semiconductor devices, so that these losses come to be significant elements on design for motors used for variable V/F. In this paper, therefore, the effects of the losses are discussed, in the case the source is generated by square wave and PWM Inverter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.301-303
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• 2001

In this paper we present a Capacitor Charging Power Supply (CCPS) using a series-resonant three-level inverter topology to improve voltage regulation and use semiconductor switches having low blocking voltage capability such as MOSFETs. This inverter can be operated with two modes, Full Power Mode (FPM) and Half Power Mode (HPM). In FPM inverter supplies the high frequency step up transformer with full DC-link voltage and in HPM with half DC-link voltage. HPM switching method will be adopted when CCPS output voltage reaches the preset target value and operates in refresh mode-charge is maintained on the capacitor. In this topology each semiconductor devices blocks a half of the DC-link voltage[2]. A 15kW, 30kV CCPS has been built and will be tested for an electric precipitator application. The CCPS operates from an input voltage of 500VDC and has a variable output voltage between 10 to 30kV and 1kHz repetition rate at 44nF capacitive load [3]. A resonant frequency of 67.9kHz was selected and a voltage regulation of $0.83\%$ has been achieved through the use of half power mode without using the forced cut off the switch current [1]. The theory of operation, circuit topology and test results are given.

• Journal of Power Electronics
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• 제14권2호
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• pp.292-301
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• 2014

This paper presents a new configuration for a three-phase multilevel voltage source inverter. The main bridge is built from a classical three-phase two-level inverter and three bidirectional switches. A variable DC-link employing two unequal DC voltage supplies and four switches is connected to the main circuit in such a way that the proposed inverter produces four levels in the output voltage waveform. In order to obtain the desired switching gate signals, the fundamental frequency staircase modulation technique is successfully implemented. Furthermore, the proposed structure is extended and compared with other types of multilevel inverter topologies. The comparison shows that the proposed inverter requires a smaller number of power components. For a given number of voltage steps N, the proposed inverter requires N/2 DC voltage supplies and N+12 switches connected with N+7 gate driver circuits, while diode clamped or flying capacitor inverters require N-1 DC voltage supplies and 6(N-1) switches connected with 6(N-1) gate driver circuits. A prototype of the introduced configuration has been manufactured and the obtained simulation and experimental results ensure the feasibility of the proposed topology and the validity of the implemented modulation technique.

• Journal of Magnetics
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• 제15권4호
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• pp.213-220
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• 2010

Since the hypothalamus immediately reacts to a nerve by processing all the information from the human body and the external stimulus being conducted, it performs a significant role in internal secretion; thus, a diverse and rapid stimulus pulse is required. By detecting Zero Detector accurately via the application of AVR on-Chip (ATMEL) using commercial electricity, chopping generates a stimulus pulse to the brain using an IGBT gate to designate a new magnetic stimulation following treatment and diagnosis. To simplify and generate a diverse range of stimuli for the brain, chopping can be used as a free magnetic stimulator. Then, commercial frequency (60Hz) is chopped precisely at the first level of the leakage transformer to deliver an appropriate stimulus pulse towards the hypothalamus when necessary. Discharge becomes stable, and the chopping frequency and duty-ratio provide variety after authorizing a high-pressure chopping voltage at the second level of the magnetic stimulator. These methods have several aims. The first is to apply a variable stimulus pulse via accurate switching frequency control by a voltaic pulse or a pulse repetition rate, according to the diagnostic purpose for a given hypothalamus. Consequently, the efficiency tends to increase. This experiment was conducted at a maximum of 210 W, a magnetic induced amplitude of 0.1~2.5 Tesla, a pulse duration of $200{\sim}350\;{\mu}s$, magnetic inducement of 5 Hz, stimulus frequency of 0.1~60 Hz, and a duration of stimulus train of 1~10 sec.

• 조명전기설비학회논문지
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• 제20권2호
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• pp.16-23
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• 2006

본 논문에서는 고역률을 가지고 영전압 스위칭으로 동작되는 새로운 단일 전력단 고주파 공진 인버터 링크형 DC-DC 컨버터 회로에 관하여 기술하고 있다. 제안된 토폴로지는 역률 교정기로써 하프 브리지형 부스트 컨버터와 하프 브리지 고주파 공진 컨버터를 단일 전력단으로 일체화 시켰다. 역률 보상용 부스트 컨버터의 부스트 인덕터 전류를 가변 스위칭 주파수와 일정 듀티비를 가지고 불연속 전류 모드(DCM)로 동작시킴으로써 부가적인 입력 전류제어기 없이 높은 입력 역률을 얻을 수 있다. 또 제안한 토폴로지의 이론해석을 무차원화 파라미터를 도입하여 범용성 있게 하여 회로 설계 전단계에서 필요한 특성값을 도식적으로 표현하다. 첨가해, 제안한 토폴로지의 상용화 가능성과 이론해석의 정당성을 입증하기 위해 스위칭 소자로 Power-MOSFET IRF 740을 제안회로 토폴로지의 스위칭 소자로 채용해 실험 장치를 구성하여 검토를 행하였다. 제안된 컨버터는 향후 통신용 DC/DC 컨버터의 전원장치, 방전등용 진원장치 등의 전원시스템에 유용히 사용될 것으로 사료된다.