• Title/Summary/Keyword: Space harmonic analysis method

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Analysis and simulation of Cascaded H-bridge 7 level inverter for eliminating typical harmonic waveforms (특정 고조파 제거를 위한 Cascaded H-bridge 7레벨 인버터의 특성해석 및 시뮬레이션)

  • Jin, Sun-Ho;Oh, Jin-Suk;Jo, Kwan-Jun;Kwak, Jun-Ho;Lim, Myoung-Kyu;Kim, Jang-Mok
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.06a
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    • pp.1022-1028
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    • 2005
  • This paper is presented the analysis results and simulation results of cascaded H-bridge 7 level inverter with various modulation index. Stepped waveform having number of switching was used to eliminate harmonic components. Switching angles according to modulation index are calculated numerically. Therefore, 3 times of switching with 7 level topology and QWS(Quarter Wave Symmetry) could eliminate 5th and 7th harmonics. The harmonic characteristics are compared to those of space vector modulation method which known as common modulation method in industrial field. Stepped waveform method showed higher ability to reduce, especially lower order of harmonics.

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Global GPS Ionospheric Modelling Using Spherical Harmonic Expansion Approach

  • Choi, Byung-Kyu;Lee, Woo-Kyung;Cho, Sung-Ki;Park, Jong-Uk;Park, Pil-Ho
    • Journal of Astronomy and Space Sciences
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    • v.27 no.4
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    • pp.359-366
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    • 2010
  • In this study, we developed a global ionosphere model based on measurements from a worldwide network of global positioning system (GPS). The total number of the international GPS reference stations for development of ionospheric model is about 100 and the spherical harmonic expansion approach as a mathematical method was used. In order to produce the ionospheric total electron content (TEC) based on grid form, we defined spatial resolution of 2.0 degree and 5.0 degree in latitude and longitude, respectively. Two-dimensional TEC maps were constructed within the interval of one hour, and have a high temporal resolution compared to global ionosphere maps which are produced by several analysis centers. As a result, we could detect the sudden increase of TEC by processing GPS observables on 29 October, 2003 when the massive solar flare took place.

Solar Cyclic Modulation of Diurnal Variation in Cosmic Ray Intensity

  • Park, Eun Ho;Jung, Jongil;Oh, Suyeon;Evenson, Paul
    • Journal of Astronomy and Space Sciences
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    • v.35 no.4
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    • pp.219-225
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    • 2018
  • Cosmic rays are ions that move at relativistic speeds. They generate secondary cosmic rays by successive collisions with atmospheric particles, and then, the secondary particles reach the ground. The secondary particles are mainly neutrons and muons, and the neutrons are observed by the ground neutron monitor. This study compared the diurnal variation in cosmic ray intensity obtained via harmonic analysis and that obtained through the pile-up method, which was examined in a previous study. In addition, we analyzed the maximum phase of the diurnal variation using four neutron monitors with a cutoff rigidity below approximately 6 GV, located at similar longitudes to the Oulu and Rome neutron monitors. Expanding the data of solar cycles 20-24, we examined the time of the maximum cosmic ray intensity, that is, the maximum phase regarding the solar cyclic modulation. During solar cycles 20-24, the maximum phase derived by harmonic analysis showed no significant difference with that derived by the pile-up method. Thus, the pile-up method, a relatively straightforward process to analyze diurnal variation, could replace the complex harmonic analysis. In addition, the maximum phase at six neutron monitors shows the 22-year cyclic variation very clearly. The maximum phase tends to appear earlier and increase the width of the variation in solar cycles as the cutoff rigidity increases.

Design of small slotless BLDC motor for robot using Space Harmonic Analysis Method (공간 고조파 해석 기법을 이용한 로봇용 소형 Slotless BLDC Motor 설계)

  • Kim, Hong-Seok;Kim, Sung-Jin;Kang, Gyu-Hong
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1132-1134
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    • 2005
  • This paper presents a design strategy of Slotless type BLDC motor using the space harmonic field method. The distribution of Back emf and torque are considered by movement of the Permanent Magnet and armature current. The result of magnetic field distribution, back-emf, and torque are in agreement with FEM.

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Torque Density Improvement of Five-Phase PMSM Drive for Electric Vehicles Applications

  • Zhao, Pinzhi;Yang, Guijie
    • Journal of Power Electronics
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    • v.11 no.4
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    • pp.401-407
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    • 2011
  • In order to enhance torque density of five-phase permanent magnetic synchronous motor with third harmonic injection for electric vehicles (EVs) applications, optimum seeking method for injection ratio of third harmonic was proposed adopting theoretical derivation and finite element analysis method, under the constraint of same amplitude for current and air-gap flux. By five-dimension space vector decomposition, the mathematic model in two orthogonal space plane, $d_1-q_1$ and $d_3-q_3$, was deduced. And the corresponding dual-plane vector control method was accomplished to independently control fundamental and third harmonic currents in each vector plane. A five-phase PMSM prototype with quasi-trapezoidal flux pattern and its fivephase voltage source inverter were designed. Also, the dual-plane vector control was digitized in a single XC3S1200E FPGA. Simulation and experimental results prove that using the proposed optimum seeking method, the torque density of five-phase PMSM is enhanced by 20%, without any increase of power converter capacity, machine size and iron core saturation.

Maximum Thrust Design of Permanent Magnet Linear Synchronous Motor Using Genetic Algorithm and Surface Harmonic Method (유전알고리즘과 공간고조파법을 이용한 PMLSM의 출력 최대화 설계)

  • Lee, Dong-Yeup;Yoon, Kang-Jun;Kim, Gyu-Tak
    • Proceedings of the KIEE Conference
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    • 2003.10b
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    • pp.66-68
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    • 2003
  • This paper is deal with the method of design for the optimum model using genetic algorithms in slotted Permanent Magnet Linear Synchrous Motor (PMLSM). The objective functions are maximum thrust and minimum detent force. Characteristic analysis method is used 2D space harmonic analysis method. Design parameters are PM width, PM height and slot width.

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Design and Characteristics Analysis of the 78 kWe Grade Synchronous Generator for Disused Diesel Engines

  • Youn, Jun-Seop;Kim, Hae-Joong;Kim, Youn-Hwan;Moon, Jae-Won
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.122-132
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    • 2017
  • This study dealt with the design process of the 78 kW permanent magnet synchronous generator for engines. After the calculation of the basic dimensions through a theoretical method in the process of initial model design, FEA (finite-element analysis) and a d,q-axis equivalent circuit were used to identify the generator characteristics depending on the number of poles. With the use of the space harmonic analysis method, the back-EMF (electromotive force) and THD were checked, and then the number of slots was determined. In addition, the most optimized generator dimensions were determined through a sizing optimization technique. Based on this, the optimum model with enhanced efficiency, material costs, and temperature characteristics was derived, and the availability of the design method was confirmed through a comparative analysis of the initial and optimum models.

Modal Analysis on SPL of the Periodic Structure depend on Unsymmetrical Beam Space (비대칭형 보강재 간격에 따른 주기구조물의 SPL모드 해석)

  • 김택현;김종태
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.1
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    • pp.52-60
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    • 2002
  • The purpose of this research is to study the vibration and acoustic pressure radiation from a thin isotropic flat plate stiffened by a rectangular array of beams, and excited by a time harmonic point force. These constructions on aircraft and ship structures are often subjected to fiequency dependent pressure fluctuations and forces. Forces from the these excitations induce structural vibrations in a wide range of fiequencies, which may cause such things as acoustic fatigue and internal cabin noise in the aircraft. It is thus important that the response characteristics and vibration modes of such periodic structures be horn. From this theoretical model, the sound pressure levels(SPL) in a semi-infinite fluid(water) bounded by the plate with the variation in the locations of an external time harmonic point farce on the plate can be calculated efficiently using three numerical tools such as the Gauss-jordan method the LU decomposition method md the IMSL numerical package.

The Harmonic Reduction Design of IPMSM No-load line-line Back-EMF for ISG (ISG용 매입형 영구자석 동기 전동기 무부하 선간 역기전력 고조파 저감설계)

  • Lee, Jin-Gyu;Jung, Jae-Woo;Kim, Sung-Il;Hong, Jung-Pyo
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.754-755
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    • 2008
  • This paper presents a method for reducing the Total Harmonic Distortion(THD) of line-line back_EMF of the IPMSM with distributed winding under the no-load condition. Firstly, the specific harmonic components of line-line back EMF are reduced considering with winding factor. Secondly, THD of line-line back EMF is minimized according to change of pole angle using by Space harmonic Analysis. Finally, the optimal design for minimizing the THD is conducted using response surface methodology with finite element analysis. The validity of the design method dealt with in this paper is demonstrated by comparison between the THD of optimal model and initial model.

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A Study on the Novel Space Vector Based Harmonic Elimination Method of Inverter (인버터 고조파 저감을 위한 새로운 공간벡터 변조기법에 관한 연구)

  • Lee, Sang-Taik;Kim, Hee-Jun;Oh, Won-Seok;Shin, Tae-Hyun
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.1236-1238
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    • 2000
  • This paper considers the problem of eliminating harmonics in the inverter output waveforms. The approach is based on the minimization of the current harmonics in the induction motor by space vector modulation method. Reference voltage is compensated with injection of controlled current harmonics which are calculated to reduce current harmonics through sampled current harmonic analyzing algorithm. The theoretical analysis is carried out using computer simulation. It is verified that proposed SVM technique could reduce current harmonic component and improve THD.

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