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저주파수 대역 무선전력전송 시스템에 의한 불균일 전자파 인체 노출량 분석
안장용,홍선의,최형도,안승영 한국전자파학회 2020 한국전자파학회논문지 Vol.31 No.10
10 MHz 이하 저주파수 대역에서 무선전력전송 시스템의 전자파에 의한 인체 내부의 전류밀도 및 유도 전기장은 복셀기반의 인체 모델을 사용하여 자기 준정적 근사 방법으로 계산된다. 복셀 기반의 인체 모델을 이용한 수치해석 과정에서분할 및 이산화 등으로 발생할 수 있는 계산 불확도를 보완하기 위해 인체 노출량 평가에는 99th percentile을 적용한다. 본 논문에서는 사용 환경 및 시스템 특성이 서로 다른 두 무선전력전송 시스템에서 percentile에 따른 전류밀도 및 유도전기장 특성을 분석하고, 각 percentile 적용에 따른 인체 노출량 평가 결과를 분석하였다.
안장용,김제독,박동렬,김해림,안승영 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.1
This paper proposes a control method for an active shield system using an independent power source under misalignment conditions. The proposed method controls the current strength and phase of the shielding system according to magnetic field leakage characteristics with high shielding performance (SP) under misalignment conditions. The current strength and phase of the shielding system were determined by the current strength and mutual inductance of the wireless power transfer (WPT) and shielding coils. Additionally, we considered x and y misalignment conditions and analyzed SP and power transfer efficiency (PTE). The proposed method was verified through simulations and experiments in terms of SP and PTE. The experiments confirmed that, due to the shielding system control, SP increased from 49.22% to 61.74% under misalignment conditions, but there was no additional PTE reduction due to shielding coil control under these conditions.
송익환,안장용,김지성 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.4
In this paper, we developed an iterative method for modeling a wireless power transfer (WPT) system with nonlinearity. The proposed method can determine the steady-state characteristics of the nonlinear rectifier circuit based on the converging iteration. Additionally, the transfer response of the receiving voltage can be identified with respect to the operating frequency by employing the proposed method in the frequency domain. The proposed method was applied to a WPT system that was designed based on the Qi specification. The circuit simulation and measurement results successfully validated the application of the proposed iterative method.
김동욱,안장용,안승영 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.2
Microrobots can be utilized in various applications, but their ability to move and perform tasks in various environments is especially important. In this paper, we introduce a 3-mm microrobot that can move in a liquid-filled tube, such as a vein, against gravity using an external wireless power transfer-based microrobot propulsion system. The force required to move against gravity was determined by calculating the effects of buoyance and gravity on the microrobot. Based on this information, the current required for the transmitting coil to induce sufficient propulsion was derived using the relation between the incident magnetic field and the magnetic force on a magnetic material. The propulsion system was experimentally tested, and the microrobot successfully moved upward against gravity. In addition, the level of human exposure to the applied electromagnetic field was determined to be within recommended guidelines using the electromagnetic simulation software Sim4Life.
손등 정맥 패턴의 회전 왜곡을 보상한 개인 식별 알고리즘의 연구
최환수,안장용 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-
This paper proposes an enhanced algorithm for person identification system utilizing hand vein pattern. The conventional algorithm does not cope with distortion caused by image rotation caused by misplaced hands on the imaging device. A straightforward approach to consider the rotaional compensation required too much computational load, thus, we devised an approach to expect the rotation direction along with image translation, reducing the compuational requirement dramatically. In this paper, we present the detail of the algorithm with experimental results with the new algorithm.