• Journal of Power Electronics
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• v.1 no.2
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• pp.78-87
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• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.442-446
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• 2004

KOMPSAT series use software-controlled unregulated bus system in which the main bus is directly connected to a battery and the duty-ratio for PWM switch is controlled by the on-board satellite software. This paper proposes a new power-stage circuit that can be available for modularization of the power regulator which is used at the software-controlled unregulated bus system satellite. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. We constructs a parallel-module converter which is composed of proposed power-stages and perform experiment to verify modular characteristics of the proposed power-stage. Finally, we verify the usefulness of the proposed power-stage by comparing above results with those of a parallel-module converter made of conventional power-stages.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.71-77
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• 2019

This study proposes a circulating current reduction method that uses high-frequency voltage compensation when carrier phase difference occurs between two inverters in MSIS. In MSIS, inverters are configured in parallel to increase power capacity and to increase efficiency by using inverters only as needed. However, in the parallel inverter structure, circulating current is inevitably generated. Circulating current increases the stress on the switch, adversely affects the current control performance, and renders load sharing difficult. The proposed method compensates for the output voltage reference of the slave module by using the high-frequency voltage so that the switching pattern of each module is matched even in asynchronous carriers. The validity of the proposed method is verified by simulations and experiments with 600 W IPMSM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.461-466
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• 2016

In this paper, a capsule body shaped surveillance/monitoring device is developed. The device includes a camera and GPS module to transmit live video data and real time GPS coordinates respectively using the Intel Edison module. A control application is developed for the smart phones and tablets to wirelessly view the live video stream and location of the capsule device and also to switch between the multiple capsule devices installed at different locations. The coordination between the developed device and the smart phone / tablet is done using the wireless function of the Intel Edison module.

• Journal of Power Electronics
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• v.17 no.1
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• pp.222-231
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• 2017

In this paper, a new architecture for a cost-effective power conditioning systems (PCS) using a single-sourced asymmetric cascaded H-bridge multilevel inverter (MLI) for photovoltaic (PV) applications is proposed. The asymmetric MLI topology has a reduced number of parts compared to the symmetrical type for the same number of voltage level. However, the modulation index threshold related to the drop in the number of levels of the inverter output is higher than that of the symmetrical MLI. This problem results in a modulation index limitation which is relatively higher than that of the symmetrical MLI. Hence, an extra voltage pre-regulator becomes a necessary component in the PCS under a wide operating bias variation. In addition to pre-stage voltage regulation for the constant MLI dc-links, another auxiliary pre-regulator should provide isolation and voltage balance among the multiple H-bridge cells in the asymmetrical MLI as well as the symmetrical ones. The proposed PCS uses a single-ended DC-DC converter topology with a coupled inductor and charge-pump circuit to satisfy all of the aforementioned requirements. Since the proposed integrated-type voltage pre-regulator circuit uses only a single MOSFET switch and a single magnetic component, the size and cost of the PCS is an optimal trade-off. In addition, the voltage balance between the separate H-bridge cells is automatically maintained by the number of turns in the coupled inductor transformer regardless of the duty cycle, which eliminates the need for an extra voltage regulator for the auxiliary H-bridge in MLIs. The voltage balance is also maintained under the discontinuous conduction mode (DCM). Thus, the PCS is also operational during light load conditions. The proposed architecture can apply the module-integrated converter (MIC) concept to perform distributed MPPT. The proposed architecture is analyzed and verified for a 7-level asymmetric MLI, using simulation results and a hardware implementation.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.2
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• pp.84-91
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• 2003

KOMPSAT series use software-controlled unregulated bus system in which the main bus is directly connected to a battery and the duty-ratio for PWM switch is controlled by the on-board satellite software. This paper proposes a new power-stage circuit that can be available for modularization of the power regulator which is used at the software-controlled unregulated bus system satellite. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. We construct a parallel-module converter which is composed of proposed power-stages and perform experiment to verify modular characteristics of the proposed power-stage. Finally, we verify the usefulness of the proposed power-stage by comparing above results with those of a parallel-module converter made of conventional power-stages.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.1
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• pp.19-22
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• 1978

A modular microcomputer system based on the Intel 8080 microprocessor is designed. Each module communicate via common bus system. The different modules can be placed anywhere on the bus. Address for memory and I/O modules are determined by switch registers situated on the modules. The system is intended to be used as a base equipment for continuing study, expansion, development and for teaching students.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.970-977
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• 2007

Absolute position detector which is one of the major equipment in the field of factory automation, not only perceives the absolute position of the rotary machine but also outputs switch data according to the given angle. Absolute position detector is composed of sensor module and its controller. In this paper, a sensor driver is implemented using FPGA with VHDL. This chip has a less form factor than conventional circuit. A test shows reliable precision within THD(total harmonic distortion) of 0.2% which can be applicable commercially. Also, FPGA-based phase error compensation methods were newly discussed. In the future, more research will be conducted to enhance the precision by the introduction of 3-phase transformer.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1660-1661
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• 2011

본 논문에서는 7중 대역 (GSM850, GSM900, DCS1800, PCS1900, UMTS850, UMTS1900, UMTS2100) 을 지원하는 LPF 내장형 LTCC 프런트 엔드 모듈 (FEM) 을 설계, 제작 및 측정하였다. 제작된 FEM은 효과적인 고조파 제거를 위해 수동소자를 LTCC 기판에 내장하여 저역 통과 필터(LPF)를 구현하였다. 본 논문에서 제안하는 FEM은 송수신 신호를 선택하기 위한 flip-chip 형태의 CMOS RF SP9T switch, Rx 신호의 수신을 위한 dual type의 SAW filter, 매칭 및 ESD 보호 회로를 위한 0603 크기의 칩소자가 부품 외부에 실장되어 구현된다. 전체 크기는 $4.5{\times}3.2{\times}1.2\;mm^3$의 초소형으로 내부 GND 2개 층을 포함하여 총 16층으로 구성된다. 측정결과는 송신단과 수신단의 삽입손실이 각각 1.7 dB, 3.6 dB 이하의 우수한 특성을 보였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.768-772
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• 2007

Integration of RF front end module(FEM) into the antenna has been investigated in USPCS band (1.88GHz-1.99GHz). The FEM consists of input filter, power amplifier, coupler, power detector, bias switch and duplexer. The antenna was designed in planar inverted F antenna(PIFA) structure to implement it inside the handset. In order to avoid strong coupling between the antenna and FEM, a shielding ground layer was placed between them. The antenna size is 19mm by 10mm by 6mm under which FEM whose size is 8mm by 5mm by 1.5m locates. The antenna impedance was selected to match to FEM having better efficiency rather than gain since FEM has enough gain whose system spec is minimum of 20dB. The antenna patterns are shown with and without FEM.