• Journal of Power Electronics
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• 제13권6호
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• pp.919-927
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• 2013

This paper proposes a Boundary Current Mode (BCM) control scheme to realize soft switching on a conventional single phase full bridge DC/AC inverter. This technique with the advantages of no auxiliary components, low cost, high efficiency, and simple in control, is attractive for micro-inverter applications. The operation principle and characteristic waveforms of the proposed soft switching technique are analyzed in theory. A digital controller is provided based on that theory. To balance the requirements of efficiency, switching frequency, and inductor size, the design considerations are discussed in detail to guide in BCM inverter construction. A 150W prototype is built under these guidelines to implement the BCM control scheme. Simulation and experiment results demonstrate the feasibilities of the proposed soft switching technique.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제5B권4호
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• pp.312-316
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• 2005

The single phase induction motor has been commonly applied to small-sized electrical appliances because of its low cost, but it has low efficiency and large torque ripple, and it is incapable of speed control. However, two-phase induction motors have small torque ripple, high efficiency and variable speed control, because they are inverter fed. In this paper, the dynamic characteristics of the two-phase induction motor, such as the torque ripple, current and speed, are analyzed by using the time-stepping finite element method, and compared with the cage-type single phase induction motor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권6호
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• pp.359-367
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• 2004

The switched reluctance motor(SRM) has considerable potential for industrial applications because of its high result lily as a result of the absence of rotor windings. In some applications with SRM, paralleling strategy is often used for cost saving, increasing of current capacity and system reliability. A SRM inverter has very low ,switching frequency. This results in reducing the burden for a high-speed of the gate-amp interface circuit. and the linearity of optocoupler is used to protect the instantaneous peak current for the stable operation. In this paper, series resistor is used to equal the current sharing of each switching device and a linear gate-amp is proposed to protect the instantaneous peak current which occurs in transient state. The proposed paralleling strategy is verified by experimental results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권3호
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• pp.180-187
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• 2004

A conventional power supply of a microwave oven has a 60Hz transformer and high voltage capacitor(HVC). Though it is very simple and has low cost, it has several problems such as large size, heavy weight and low efficiency To improve these problems, various high frequency inverter type power supply have been investigated and developed in recent years. But these cost is higher than the conventional one due to additional control circuit, fast switching devces. In this paper, a novel pulse power supply for microwave oven using high frequency transformer embedded HVC(High Voltage Capacitor) is proposed for down-sizing, cost reduction and efficient improvement. To verify the effectiveness of the proposed transformer, an equivalent circuit of transformer embedded HVC is derived and it's characteristic is described. And the validity of the proposed pulse power supply embedded HVC-high frequency transformer is shown by simulations and experiments accroding to various operating conditions.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 Proceedings of 6th International Joint Symposium on Microeletronics and Packaging
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• pp.9-25
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• 2001

Fairchild has been developing a new class IPM called SPM consisting of dramatic Packaging technology to achieve the lowest cost rind better performance for low power home appliances and industrial AC drive applications. The first Fairchild SPM development with IGBT 600V/15A for washing machine application started in 1999 and was completed successfully. Fairchild SPMs are going to be the best solution for low power inverter-driven AC drive system after 2001. The new SPM Packages like SPM ∥ and SPIM for the next generation IPM with the highest competitiveness (cost & performance) shall be continuouslly developed.

• Journal of Power Electronics
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• 제15권1호
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• pp.256-267
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• 2015

Grid-connected transformerless photovoltaic (PV) inverters (TPVIs) are increasingly dominating the market due to their higher efficiency, lower cost, lighter weight, and reduced size when compared to their transformer based counterparts. However, due to the lack of galvanic isolation in the low voltage grid interconnections of these inverters, the PV systems become vulnerable to leakage currents flowing through the grounded star point of the distribution transformer, the earth, and the distributed parasitic capacitance of the PV modules. These leakage currents are prohibitive, since they constitute an issue for safety, reliability, protection coordination, electromagnetic compatibility, and module lifetime. This paper investigates a wide range of multi-kW range power rating TPVI topologies and classifies them in terms of their leakage current attributes. This systematic classification places most topologies under a small number of classes with basic leakage current attributes. Thus, understanding and evaluating these topologies becomes an easy task. In addition, based on these observations, new topologies with reduced leakage current characteristics are proposed in this paper. Furthermore, the important efficiency and cost determining characteristics of converters are studied to allow design engineers to include cost and efficiency as deciding factors in selecting a converter topology for PV applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.163-165
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• 2004

A low-cost electronic ballast using a conventional HID controller IC is proposed. The proposed ballast consists of high frequency DC-DC converter, low frequency DC-AC inverter, and igniter circuit. This ballast shows hot-restrike, suitable operation at each stage of various lamp state and stable operation in steady-state.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1015-1024
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• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• 전기전자학회논문지
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• 제24권1호
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• pp.364-367
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• 2020

본 논문에서는 OR논리게이트를 적용한 순차전압제어방식의 독립형 PV-ESS 시스템을 나타내고 있다. 저압연계방식으로 용량확대에 따른 문제점들을 가지고 있었던 기존 독립형 PV-ESS 시스템에 고압의 아날로그 방식의 순차전압제어 방식을 적용함으로써 고효율, 저가격이 가능한 독립형 PV-ESS 시스템을 제안한다. 본 논문은 기존 24V 태양광 단위 모듈의 직렬연결 확장형 고압 배터리의 출력전압 384V을 3상 DC to AC 인버터의 입력 전압으로 하여 인버터의 출력 전압과 출력 전력을 AC380V@60Hz와 10kW로 구성하였다. PSIM 시뮬레이션에 의한 이론 해석의 타당성을 입증하기 위해 실험을 통해 OR 논리 게이트를 적용한 순차전압제어시스템의 동작 특성을 확인하였다.

• 조명전기설비학회논문지
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• 제20권3호
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• pp.36-44
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• 2006

일반적으로 PWM인버터에 발생된 고조파와 노이즈는 스위칭 주파수, dv/dt와 di/dt, PWM 스위칭 방법에 의해 영향을 받는다. 멀티레벨 인버터가 고전력 시스템에 적용되어 낮은 주파수에서 동작할 때 이것은 큰 고조파 성분과 노이즈를 발생하게 된다. 따라서 멀티레벨 인버터에 출력 필터가 요구된다. 본 논문에서는 H-bridge 7레벨 인버터 시스템을 사용한 3상 유도 전동기 구동 시스템의 고조파와 노이즈 감소를 위해 출력 필터를 설계하였다. 가격이 저렴하고 간단한 구조를 가지며, 고조파와 노이즈를 효과적으로 감소시킬 수 있는 수동필터는 멀티레벨 인버터 시스템을 사용한 3상 유도전동기 구동시스템에 적용되었다. 설계된 시스템은 향상되었고, 시뮬레이션과 실험을 통해 그 타당성을 증명하였다.