• Journal of Power Electronics
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• 제16권5호
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• pp.1802-1812
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• 2016

Cross regulation is a key technical issue of single-inductor multiple-output (SIMO) DC-DC converters. This paper investigates the cross regulation in single-inductor dual-output (SIDO) Buck converters with continuous conduction mode (CCM) operation. The expressions of the DC voltage gain, control to the output transfer function, cross regulation transfer function, cross coupled transfer function and impedance transfer function of the converter are presented by the time averaging equivalent circuit approach. A small signal model of a SIDO CCM Buck converter is built to analyze this cross regulation. The laws of cross regulation with respect to various load conditions are investigated. Simulation and experiment results verify the theoretical analysis. This study will be helpful for converter design to reduce the cross regulation. In addition, a control strategy to reduce cross regulation is performed.

• International journal of advanced smart convergence
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• 제7권1호
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• pp.7-14
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• 2018

In this paper, we derive a transfer function of cross-coupled microwave filter systems by using a characteristics of chain matrices. Depending on the lumped element of capacitor or inductor, the cross-coupled system is negatively- or positively system. We used a ladder network as a starting system composed of several subsystems connected in chain. Each subsystem is descrived by Laplace impedance. By solving the transmission zero characteristic equation derived from the cascaded subsystems, we can find the zeros of filter system with externally cross-coupled lumped elements. With the cross-coupled elements of capacitors, the numerator polynomial of system transfer function is used to locate the quadruplet zeros in complex plane. We show the polynomoials of numerator and denominator of cascaded transfer function, obtaining the zeros of the cross-coupled system.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1134-1138
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• 2008

본 논문에서는 전력분배기의 설계에 필수적인 분포정수 임피던스 변환기의 합성법을 제시하고, 이에 의하여 광대역 전력분배기를 설계한다. 변환기의 전달함수는 Chebyshev 근사로 합성하며, 변환기의 소자값은 최소 삽입손실(MIL)과 리플에 대하여 계산된다. 변환기의 요구 성능은 전달함수의 MIL과 리플을 최적화함으로써 구할 수 있다. 이의 응용 예로써 $2{\sim}8GHz$에서 동작하는 4-경로 전력분배기(four-way power divider)를 설계하였다. 실험 결과, 전력분배기는 주어진 주파수 대역에서 설계치에 근접하는 성능을 나타내어, 분포정수 회로합성에 의한 변환기의 설계는 전력분배기의 설계에 유용하게 사용될 수 있음을 입증하였다.

• Journal of Power Electronics
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• 제17권1호
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• pp.305-313
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• 2017

A novel interference isolation method is proposed by using several designed coils in capacitive power transfer systems as isolation impedances. For each designed coil, its stray parameters such as the inter-turn capacitance, coil resistance and capacitance between the coil and the core, etc. are taken into account. An equivalent circuit model of the designed coil is established. According to this equivalent circuit, the impedance characteristic of the coil is calculated. In addition, the maximum impedance point and the corresponding excitation frequency of the coil are obtained. Based on this analysis, six designed coils are adopted to isolate the interference from power delivery. The proposed method is verified through experiments with a power carrier frequency of 1MHz and a data carrier frequency of 8.7MHz. The power and data are transferred parrallelly with a data carrier attenuation lower than -5dB and a power attenuation on the sensing resistor higher than -45dB.

• Corrosion Science and Technology
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• 제9권4호
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• pp.153-158
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• 2010

Electrical appliances such as audiovisual equipment and personal computers have recently had heat and electromagnetic problems. In order to solve those problems, 'High heat absorbing pre-painted steel sheet (hereinafter referred to as PSS)', 'High electromagnetic shielding PSS' and 'High heat absorbing and high electromagnetic shielding PSS' have been developed. In this paper, the heat characteristics and electromagnetic shielding properties of PSS are investigated by methods that use enclosures and their mechanisms are discussed. It was found that 'High heat absorbing PSS' and 'High heat absorbing and high electromagnetic shielding PSS'could reduce the heat problem. The mechanism of the heat characteristics was presumed for the high heat absorptivity of the back coating inside the enclosure. And it was also found that 'High electromagnetic shielding PSS' and 'High heat absorbing and high electromagnetic shielding PSS' could shield electromagnetic waves well. The mechanism of the electromagnetic shielding properties was considered for the low transfer impedance of the back coating inside the enclosure. 'High heat absorbing PSS' and 'High electromagnetic shielding PSS' have been adopted as materials for electrical appliances and 'High electromagnetic shielding and high heat absorbing PSS' have been tested for that purpose.

• 전기학회논문지
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• 제64권4호
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• pp.560-566
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• 2015

The self-consistent simulation based on the drift-diffusion approximation with anisotropic transport coefficients was performed. The RHCP-wave propagation was observed in MICP and this wave was refracted toward the high-density region. The calculated impedance seen from the antenna terminal shows that resistance component of MICP is a higher than that of ordinary ICP. Because of a higher resistance, the power transfer efficiency was improved to 95%. This property is practically important for large-size, low-pressure plasma sources because high resistance corresponds to high power-transfer efficiency and stable impedance matching characteristics.

• 전력전자학회논문지
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• 제22권6호
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• pp.469-475
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• 2017

Using impedance matching techniques as a way to increase system power transferability in capacitive wireless power transmission has been widely investigated in conventional studies. However, these techniques tend to increase the circuit volume and thus counterbalance the advantage of the simplicity in the energy link structure. In this paper, a compact circuit topology with one leakage-enhanced transformer is proposed in order to minimize the circuit volume for the capacitive power transfer system. This topology achieves a reactive compensation, and the system quality factor value can be reduced by the turn ratio. As a result, this topology not only reduces the overall system volume but also minimizes the voltage stress of the link capacitor. An optimal design guideline for the leakage-enhanced transformer is also presented. The advantages of the proposed scheme over the conventional method in terms of power efficiency and circuit volume are revealed through an analytic comparison. The feasibility of applying the new topology is also verified by conducting 50 W hardware tests.

• 대한조선학회논문집
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• 제42권2호
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• pp.136-141
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• 2005

An experiment method has been developed to analyse the vibration characteristics of marine propeller blades, and vibration tests have been carried out on the model scale propeller in air and in water. The driving point transfer function(acceleration/excitation force) has been measured and modified by compensating the attachment effect of the impedance head. The measured natural frequencies in air have been compared with the theoretical results by an in-house FEM code PROSTEC. The added masses have been derived by comparing the measured natural frequencies in air and in water, and the results have been compared to the results using existing formula based on experience.

• ETRI Journal
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• 제38권3호
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• pp.568-578
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• 2016

A wireless power transfer (WPT) system is usually classified as being of either a two-coil or four-coil type. It is known that two-coil WPT systems are suitable for short-range transmissions, whereas four-coil WPT systems are suitable for mid-range transmissions. However, this paper reveals that the two aforementioned types of WPT system are alike in terms of their performance and characteristics, differing only when it comes to their matching-network configurations. In this paper, we first find the optimum load and source conditions using Z-parameters. Then, we estimate the maximum power transfer efficiency under the optimum load and source conditions, and we describe how to configure the matching networks pertaining to both types of WPT system for the given optimum load and source conditions. The two types of WPT system show the same performance with respect to the coupling coefficient and load impedance. Further, they also demonstrate an identical performance in the two cases considered in this paper, that is, a strong-coupled case and a weak-coupled case.

• 대한전자공학회논문지SD
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• 제39권3호
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• pp.49-60
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• 2002

본 논문에서는 DRAM 모듈의 전원 평면에 대한 효과적인 설계 방법을 제시하였고 그 방법은 다음과 같이 세 단계로 구성되어 있다. 1) PEEC 등가회로를 이용한 2D 전송선 구조로 전원평면의 모델링 및 해석. 2) 측정값 비교를 통한 해석 결과 검증. 3) 전원 평면의 물리적 파라미터를 이용한 설계 가이드 제시. 제시한 내용을 바탕으로 하여 DRAM 모듈에서 전원 및 접지평면 성능을 안정화를 이루기 위한 효과적인 De-coupling 커패시터의 용량과 개수를 결정하는 방법을 기술하였다 이 설계 방법론은 스트립 구조 및 do-coupling 커패시터를 갖는 DRAM 모듈에서 효과적으로 사용할 수 있다.