• Title/Summary/Keyword: optimization scheme

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Improved Particle Swarm Optimization Algorithm for Adaptive Frequency-Tracking Control in Wireless Power Transfer Systems

  • Li, Yang;Liu, Liu;Zhang, Cheng;Yang, Qingxin;Li, Jianxiong;Zhang, Xian;Xue, Ming
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1470-1478
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    • 2018
  • Recently, wireless power transfer (WPT) via coupled magnetic resonances has attracted a lot of attention owing to its long operation distance and high efficiency. However, the WPT systems is over-coupling and a frequency splitting phenomenon occurs when resonators are placed closely, which leads to a decrease in the transfer power. To solve this problem, an adaptive frequency tracking control (AFTC) was used based on a closed-loop control scheme. An improved particle swarm optimization (PSO) algorithm was proposed with the AFTC to track the maximum power point in real time. In addition, simulations were carried out. Finally, a WPT system with the AFTC was demonstrated to experimentally validate the improved PSO algorithm and its tracking performance in terms of optimal frequency.

Design of Water Resource Planning System Utilizing Special Features in Mathematical Programming Data Structure (수리계획 모형 자료구조를 활용한 수자원 운영 계획 시스템의 설계)

  • Kim, Jae-Hee;Park, Youngjoon;Kim, Sheung-Kown
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2000.04a
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    • pp.160-163
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    • 2000
  • Due to the complexities of the real-world system, a water resource management program has to deal with various types of data. It appears that management personnel who has to use the program usually suffers from the technical burdens of handling large amount of data and understanding the optimization theory when they try to interpret the results. By combining the capabilities of database technology and modeling technique with optimization procedure we can develop a reliable decision supporting tool for multi-reservoir operation planning, which yields operating schedule for each dam in a river basin. We introduce two special data handling methodology for the real world application. First, by treating dams, hydro-electric power generating facilities and demand sites as separate database tables, the proposed data handling scheme can be applied to general water resource system in Korea. Second, by assigning variable names using predetermined key words, we can save searching time for identifying the moaning of the variables, so that we can quickly save the results of the optimization run to the database.

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Shape Optimization of a CRT based on Response Surface and Kriging Metamodels (반응표면과 크리깅메타모델을 이용한 CRT 형상최적설계)

  • Lee, Tae-Hee;Lee, Chang-Jin;Lee, Kwang-Ki
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.3
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    • pp.381-386
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    • 2003
  • Gradually engineering designers are determined based on computer simulations. Modeling of the computer simulation however is too expensive and time consuming in a complicate system. Thus, designers often use approximation models called metamodels, which represent approximately the relations between design and response variables. There arc general metamodels such as response surface model and kriging metamodel. Response surface model is easy to obtain and provides explicit function. but it is not suitable for highly nonlinear and large scaled problems. For complicate case, we may use kriging model that employs an interpolation scheme developed in the fields of spatial statistics and geostatistics. This class of into interpolating model has flexibility to model response data with multiple local extreme. In this study. metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube. which finds the shape minimizing the local maximum principal stress Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.

Design of Modal Transducer in 2D Structure Using Multi-Layered PVDF Films Based on Electrode Pattern Optimization (다층 압전 필름의 전극 패턴 최적화를 통한 2차원 구조물에서의 모달 변환기 구현)

  • 유정규;김지철;김승조
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.632-642
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    • 1998
  • A method based on finite element discretization is developed for optimizing the polarization profile of PVDF film to create the modal transducer for specific modes. Using this concept, one can design the modal transducer in two-dimensional structure having arbitrary geometry and boundary conditions. As a practical means for implementing this polarization profile without repoling the PVDF film the polarization profile is approximated by optimizing electrode patterns, lamination angles, and poling directions of the multi-layered PVDF transducer. This corresponds to the approximation of a continuous function using discrete values. The electrode pattern of each PVDF layer is optimized by deciding the electrode of each finite element to be used or not. Genetic algorithm, suitable for discrete problems, is used as an optimization scheme. For the optimization of each layers lamination angle, the continuous lamination angle is encoded into discrete value using binary 5 bit string. For the experimental demonstration, a modal sensor for first and second modes of cantilevered composite plate is designed using two layers of PVDF films. The actuator is designed based on the criterion of minimizing the system energy in the control modes under a given initial condition. Experimental results show that the signals from residual modes are successfully reduced using the optimized multi-layered PVDF sensor. Using discrete LQG control law, the modal peaks of first and second modes are reduced in the amount of 12 dB and 4 dB, resepctively.

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Optimization of the Number of Antennas for Energy Efficiency in Massive MIMO WPCN (Massive MIMO WPCN에서 에너지 효율 향상을 위한 안테나 수 최적화 기법)

  • Han, Yonggue;Sim, Dongkyu;Lee, Chungyong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.3
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    • pp.19-24
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    • 2015
  • We introduce an optimization of the number of base station antennas in massive multiple-input multiple-output (MIMO) wireless powered communication network (WPCN). We use channel hardening property of massive MIMO system to approximate channel gain in terms of the number of base station antennas. Then, we find an optimal solution by partial differential and obtain a closed form solution by using Lambert-W function. The simulation results show that the approximation and the method of solving the optimization problem are reasonable, and the optimal solution of proposed scheme is almost identical to the optimal number of base station antennas by the exhaustive search method.

PSO-Based Optimal PI(D) Controller Design for Brushless DC Motor Speed Control with Back EMF Detection

  • Kiree, Chookiat;Kumpanya, Danupon;Tunyasrirut, Satean;Puangdownreong, Deacha
    • Journal of Electrical Engineering and Technology
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    • v.11 no.3
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    • pp.715-723
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    • 2016
  • This paper proposes a design of optimal PI(D) controller for brushless DC (BLDC) motor speed control by the particle swarm optimization (PSO), one of the powerful metaheuristic optimization search techniques. The proposed control system is implemented on the TMS320F28335 DSP board interfacing to MATLAB/SIMULINK. With Back EMF detection, the proposed system is considered as a class of sensorless control. This scheme leads to the speed adjustment of the BLDC motor by PWM. In this work, the BLDC motor of 100 watt is conducted to investigate the control performance. As results, it was found that the speed response of BLDC motor can be regulated at the operating speed of 800 and 1200 rpm in both no load and full load conditions. Very satisfactory responses of the BLDC system can be successfully achieved by the proposed control structure and PSO-based design approach.

Comparison and Optimization of Parallel-Transmission RF Coil Elements for 3.0 T Body MRI (3.0 T MRI를 위한 Parallel-Transmission RF 코일 구조의 비교와 최적화)

  • Oh, Chang-Hyun;Lee, Heung-K.;Ryu, Yeun-Chul;Hyun, Jung-Ho;Choi, Hyuk-Jin
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.61-63
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    • 2007
  • In high field (> 3 T) MR imaging, the magnetic field inhomogeneity in the target object increases due to the nonuniform electro-magnetic characteristics and relatively high Larmor frequency. Especially in the body imaging, the effect causes more serious problems resulting in locally high SAR(Specific Absorption Ratio). In this paper, we propose an optimized parallel-transmission RF coil element structure and show the utility of the coil by FDTD simulations to overcome the unwanted effects. Three types of TX coil elements are tested to maximize the efficiency and their driving patterns(amplitude and phase) optimized to have adequate field homogeneity, proper SAR level, and sufficient field strength. For the proposed coil element of 25 cm ${\times}$ 8 cm loop structure with 12 channels for a 3.0 T body coil, the 73% field non-uniformity without optimization was reduced to about 26% after optimization of driving patterns. The experimental as well as simulation results show the utility of the proposed parallel driving scheme is clinically useful for (ultra) high field MRI.

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Design and optimization of 900kW class PMSG, based on Unison U50 model (Unison U50 직접구동 영구자석 발전기를 기반으로 한 900kW급 동기발전기 설계 및 최적화)

  • Kim, Tae-Hun;Lee, Sang-Woo;Kim, Dong-Eon;Chung, Chin-Wha;Park, H.C.
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.423-426
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    • 2009
  • POSTECH Graduate School of Wind Energy is trying to upgrade the PMSG used for Unison U50 to 900 kW class. Intensive optimization efforts are carried out the reduce the axial size and total weight of the generator while increasing the rated output to 900 kW. The generator features 3.32m stator inner radius, 671mm stator length, 84 pole, 25 rated rpm and 31.6kN/$m^2$ shear force density. To reduce the gross weight, the stronger magnetic material is applied with optimal magnet size resulting lowest cogging torque. Also, instead of stator skewing the stator, the magnet position along the circumference is optimized to further reduce the cogging torque. This scheme eliminates the stator skewing procedure and may enhance the productivity. This method also reduces the total harmonic distortion. In this report, upgrade method, no-load line to line voltage and phase voltage, cogging torque, loss calculations and thermal analysis are presented.

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Resource Allocation with Proportional Rate In Cognitive Wireless Network: An Immune Clonal Optimization Scheme

  • Chai, Zheng-Yi;Zhang, De-Xian;Zhu, Si-Feng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.6 no.5
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    • pp.1286-1302
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    • 2012
  • In this paper, the resource allocation problem with proportional fairness rate in cognitive OFDM-based wireless network is studied. It aims to maximize the total system throughput subject to constraints that include total transmit power for secondary users, maximum tolerable interferences of primary users, bit error rate, and proportional fairness rate among secondary users. It is a nonlinear optimization problem, for which obtaining the optimal solution is known to be NP-hard. An efficient bio-inspired suboptimal algorithm called immune clonal optimization is proposed to solve the resource allocation problem in two steps. That is, subcarriers are firstly allocated to secondary users assuming equal power assignment and then the power allocation is performed with an improved immune clonal algorithm. Suitable immune operators such as matrix encoding and adaptive mutation are designed for resource allocation problem. Simulation results show that the proposed algorithm achieves near-optimal throughput and more satisfying proportional fairness rate among secondary users with lower computational complexity.

Relay Assignment in Cooperative Communication Networks: Distributed Approaches Based on Matching Theory

  • Xu, Yitao;Liu, Dianxiong;Ding, Cheng;Xu, Yuhua;Zhang, Zongsheng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.11
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    • pp.5455-5475
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    • 2016
  • In this article, we model the distributed relay assignment network as a many-to-one matching market with peer effects. We discuss two scenarios for throughput optimization of relay networks: the scenario of aggregate throughput optimization and the scenario of fairness performance optimization. For the first scenario, we propose a Mutual Benefit-based Deferred Acceptance (MBDA) algorithm to increase the aggregate network throughput. For the second scenario, instead of using the alternative matching scheme, a non-substitution matching algorithm (NSA) is designed to solve the fairness problem. The NSA improves the fairness performance. We prove that both two algorithms converge to a globally stable matching, and discuss the practical implementation. Simulation results show that the performance of MBDA algorithm outperforms existing schemes and is almost the same with the optimal solution in terms of aggregate throughput. Meanwhile, the proposed NSA improves fairness as the scale of the relay network expands.