• Title/Summary/Keyword: Sinusoidal modeling

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Voice Source Modeling Using Harmonic Compensated LF Model (LF 모델에 고조파 성분을 보상한 음원 모델링)

  • 이건웅;김태우홍재근
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.1247-1250
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    • 1998
  • In speech synthesis, LF model is widely used for excitation signal for voice source coding system. But LF model does not represent the harmonic frequencies of excitation signal. We propose an effective method which use sinusoidal functions for representing the harmonics of voice source signal. The proposed method could achieve more exact voice source waveform and better synthesized speech quality than LF model.

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Nonlinear digital simulation for the analysis of a hydraulic servo system (비선형 디지탈 시뮬레이션에 의한 유압서보 시스템 해석)

  • 이상열;문의준
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.346-351
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    • 1987
  • In this study, digital simulation with nonlinear modeling is carried out to analyse the performance of a hydraulic servomotor system developed for the position control of a large inertia. Nonlinear element, such as nonlinear pressure flow relationships of servovalve, valve spool limits, nonlinear friction, and backlash and resilience of gear system are included in the simulation along with the dynamic characteristics of variable delivery pump compensation mechanism. Simulation results are compared with experimental results for both step and sinusoidal inputs. Independent of input magnitude, both results are in good agreement with minor differences in detail.

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Circuit Models for Low Frequency Modulation Characteristics of Semiconductor Lasers (반도체 레이저의 저주파 변조특성의 회로 모델)

  • 소준호
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.214-217
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    • 1989
  • The most attractive feature of semiconductor lasers as sources for coherent optical communication system is the ability to produce frequency modulation by modulation of the bias current. The frequency deviation of semiconductor lasers under direct modulation depends on the laser structure and modulation frequency. This paper describes a circuit modeling techniques for the directly frequency modulated CSP (Channeled Substrated Planner) semiconductor laser. Predictions from this model are compared with the other published results of sinusoidal frequency modulation below than 1 GHz.

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Design of Double Digital Controller to Improve Performance for the Silent Discharging Ozonizer (무성방전 오조나이저의 성능개선을 위한 2중 디지털 제어기의 설계)

  • Park, Jee-Ho;Kim, Dong-Wan;Woo, Sung-Hoon;Roh, In-Bae;Woo, Jung-In
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.55 no.1
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    • pp.13-20
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    • 2006
  • In this paper, a control method of ozone generator for a tiny deodorizer is proposed, and also a cooling technique is described which is cooling down the flowing air gap into a silent discharger to $2[^{\circ}C]$ to generate ozone of high density and diffusing power. As the digital control system for this method, a double feedback loop is designed which detects the voltage and current of equivalent capacitor of the discharger and compensates for the poor power waveform caused by the noise at high discharging frequency. During the plant modeling of this system, computing time factor is considered as a unique parameter of the power system to improve the respond characteristics with regard to fluctuating load and to replenish the computing time delay of the controller. Through the experiment, sinusoidal input current for discharger can be acquired and all the effectiveness of this accurate control system over unstable ozone discharger are proved.

The PV System Modeling Based on the PSCAD/EMTDC (PSCAD/EMTDC를 이용한 태양광발전(PV) 모델링에 관한 연구)

  • Jeon, Jintaek;Rho, Daeseok;Kim, Chanhyeok;Wang, Yongpeel
    • Journal of the Korea Convergence Society
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    • v.2 no.3
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    • pp.15-23
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    • 2011
  • This paper deals with the analysis for the operation characteristic of PV 3 phase inverter, considering the state equation through d-q coordinates transformation, and proposes an algorithm of controlling current using PI(Proportional Integral) controller to control the output and the theory algorithm of sinusoidal PWM method to design inverter. And also this paper performs PV modelling using PSCAD/EMTDC S/W which is commonly used in analysis of distribution system and confirms effectiveness of the modelling proposed in this paper by analyzing and comparing the EMTDC/PSCAD simulation result with the theoretical method.

Three dimensional free vibration analysis of functionally graded nano cylindrical shell considering thickness stretching effect

  • Dehsaraji, Maryam Lori;Arefi, Mohammad;Loghman, Abbas
    • Steel and Composite Structures
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    • v.34 no.5
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    • pp.657-670
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    • 2020
  • In this paper, vibration analysis of functionally graded nanoshell is studied based on the sinusoidal higher-order shear and normal deformation theory to account thickness stretching effect. To account size-dependency, Eringen nonlocal elasticity theory is used. For more accurate modeling the problem and corresponding numerical results, sinusoidal higher-order shear and normal deformation theory including out of plane normal strain is employed in this paper. The radial displacement is decomposed into three terms to show variation along the thickness direction. Governing differential equations of motion are derived using Hamilton's principle. It is assumed that the cylindrical shell is made of an arbitrary composition of metal and ceramic in which the local material properties are measured based on power law distribution. To justify trueness and necessity of this work, a comprehensive comparison with some lower order and lower dimension works and also some 3D works is presented. After presentation of comparative study, full numerical results are presented in terms of significant parameters of the problem such as small scale parameter, length to radius ratio, thickness to radius ratio, and number of modes.

A analysis of Thin-Straight Monopole antenna on a conducting box Using the Wire-Grid Method (Wire-Grid 방법을 이용한 도체 상자에 부착된 선형 모노폴 안테나 해석)

  • 이승엽;김경재;이영훈;허선종;박한규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.11
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    • pp.1669-1676
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    • 1993
  • In this paper, a thin-straight monopole antenna attached to a conducting box is analyzed using a moment method with the pocklington integral expression for the exact Green's function. A modeling of a conducting box is based on a Wire-Grid method for an efficient calculation procedure. A system of linear equation is obtained using the piecewise sinusoidal basis function. And a Junction basis function is enforcing to represent the physical current on the edge of the conducting box. Especially, the junction basis functions are overlapped for the current continuity preserving on the vertexes. Numerical results are obtained for the current distribution on the unified antenna/conducting box system, input impedance and radiation pattern. The results are compared with the known data.

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Modeling for Utility Interactive Photovoltaic Power Generation System using PSCAD/EMTDC (PSCAD/EMTDC를 이용한 태양광 발전시스템의 배전계통 연계운전을 위한 모델링)

  • Kim, Woo-Hyun;Kang, Min-Kyu;Kim, Eung-Sang;Kim, Ji-Won;Ro, Byong-Kwon;Yu, In-Keun
    • Proceedings of the KIEE Conference
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    • 1999.07c
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    • pp.1180-1182
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    • 1999
  • Modeling for utility interactive photovoltaic power generation system has been studied using PSCAD/EMTDC. The proposed model system consists of a simple utility circuit configuration, 3kW of single phase utility interactive photovoltaic system, single phase PWM voltage source inverter module, and feed forward PID controller as control circuit. In the system, the DC current is assumed constant, and the voltage source inverter provides sinusoidal ac current for the loads of utility system. The simulation results are given in order to verify the effectiveness of the proposed model. The phases of output voltage of utility system and the output current of the inverter module are compared. Especially, the compensation effect of the photovoltaic system for the unbalanced load is analyzed. and the transient phenomena for a phase to ground fault are also simulated.

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Experimental calibration of forward and inverse neural networks for rotary type magnetorheological damper

  • Bhowmik, Subrata;Weber, Felix;Hogsberg, Jan
    • Structural Engineering and Mechanics
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    • v.46 no.5
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    • pp.673-693
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    • 2013
  • This paper presents a systematic design and training procedure for the feed-forward back-propagation neural network (NN) modeling of both forward and inverse behavior of a rotary magnetorheological (MR) damper based on experimental data. For the forward damper model, with damper force as output, an optimization procedure demonstrates accurate training of the NN architecture with only current and velocity as input states. For the inverse damper model, with current as output, the absolute value of velocity and force are used as input states to avoid negative current spikes when tracking a desired damper force. The forward and inverse damper models are trained and validated experimentally, combining a limited number of harmonic displacement records, and constant and half-sinusoidal current records. In general the validation shows accurate results for both forward and inverse damper models, where the observed modeling errors for the inverse model can be related to knocking effects in the measured force due to the bearing plays between hydraulic piston and MR damper rod. Finally, the validated models are used to emulate pure viscous damping. Comparison of numerical and experimental results demonstrates good agreement in the post-yield region of the MR damper, while the main error of the inverse NN occurs in the pre-yield region where the inverse NN overestimates the current to track the desired viscous force.

A Study of Circulating Current in MMC based HVDC System under an Unbalanced Grid Condition (불평형 전원 조건에서 MMC 기반 HVDC 시스템 순환전류에 관한 연구)

  • Do, Won-Seok;Kim, Si-Hwan;Kim, Tae-Jin;Kim, Rae-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.8
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    • pp.1193-1201
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    • 2015
  • This paper presents a study of circulating current of modular multi-level converter (MMC) based a high voltage direct current (HVDC) system under unbalanced grid conditions. Due to the connection of a dependent DC source in each phase, the MMC system inherently generates the power ripple of double-line-frequency components in the AC-side and as a result, the additional sinusoidal current named circulating current flows through the each arm. Reliability improvement of HVDC system under an unbalanced grid condition is one of the important criteria. Generally, the modeling of the circulating current is based on the power relation between DC-side and AC-side. However, the method is not perfectly matched in the MMC system due to the difference of the structural characteristic. In this paper, improved modeling method of circulating current is proposed, which is based on the inner arm power. The proposed method is verified by several simulations to have good agreement of the circulating current components.