• Title/Summary/Keyword: Current tracking

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A Low-Computation Indirect Model Predictive Control for Modular Multilevel Converters

  • Ma, Wenzhong;Sun, Peng;Zhou, Guanyu;Sailijiang, Gulipali;Zhang, Ziang;Liu, Yong
    • Journal of Power Electronics
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    • v.19 no.2
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    • pp.529-539
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    • 2019
  • The modular multilevel converter (MMC) has become a promising topology for high-voltage direct current (HVDC) transmission systems. To control a MMC system properly, the ac-side current, circulating current and submodule (SM) capacitor voltage are taken into consideration. This paper proposes a low-computation indirect model predictive control (IMPC) strategy that takes advantages of the conventional MPC and has no weighting factors. The cost function and duty cycle are introduced to minimize the tracking error of the ac-side current and to eliminate the circulating current. An optimized merge sort (OMS) algorithm is applied to keep the SM capacitor voltages balanced. The proposed IMPC strategy effectively reduces the controller complexity and computational burden. In this paper, a discrete-time mathematical model of a MMC system is developed and the duty ratio of switching state is designed. In addition, a simulation of an eleven-level MMC system based on MATLAB/Simulink and a five-level experimental setup are built to evaluate the feasibility and performance of the proposed low-computation IMPC strategy.

Maximum Power Point Tracking Control Scheme for Grid Connected Variable Speed Wind Driven Self-Excited Induction Generator

  • El-Sousy Fayez F. M.;Orabi Mohamed;Godah Hatem
    • Journal of Power Electronics
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    • v.6 no.1
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    • pp.52-66
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    • 2006
  • This paper proposes a wind energy conversion system connected to a grid using a self-excited induction generator (SEIG) based on the maximum power point tracking (MPPT) control scheme. The induction generator (IG) is controlled by the MPPT below the base speed and the maximum energy can be captured from the wind turbine. Therefore, the stator currents of the IG are optimally controlled using the indirect field orientation control (IFOC) according to the generator speed in order to maximize the generated power from the wind turbine. The SEIG feeds a (CRPWM) converter which regulates the DC-link voltage at a constant value where the speed of the IG is varied. Based on the IG d-q axes dynamic model in the synchronous reference frame at field orientation, high-performance synchronous current controllers with satisfactory performance are designed and analyzed. Utilizing these current controllers and IFOC, a fast dynamic response and low current harmonic distortion are attained. The regulated DC-link voltage feeds a grid connected CRPWM inverter. By using the virtual flux orientation control and the synchronous frame current regulators for the grid connected CRPWM inverter, a fast current response, low harmonic distortion and unity power factor are achieved. The complete system has been simulated with different wind velocities. The simulation results are presented to illustrate the effectiveness of the proposed MPPT control scheme for a wind energy system. In the simulation results, the d-q axes current controllers and DC-link voltage controller give prominent dynamic response in command tracking and load regulation characteristics.

A Maximum Power Control of IPMSM with Real-time Parameter Identification

  • Jun, Hyunwoo;Ahn, Hanwoong;Lee, Hyungwoo;Go, Sungchul;Lee, Ju
    • Journal of Electrical Engineering and Technology
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    • v.12 no.1
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    • pp.110-116
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    • 2017
  • This paper proposed a new real-time parameter tracking algorithm. Unlike the convenience algorithms, the proposed real-time parameter tracking algorithm can estimate parameters through three-phase voltage and electric current without coordination transformation, and does not need information on magnetic flux. Therefore, it can estimate parameters regardless of the change according to operation point and cross-saturation effect. In addition, as the quasi-real-time parameter tracking technique can estimate parameters through the four fundamental arithmetic operations instead of complicated algorithms such as numerical value analysis technique and observer design, it can be applied to low-performance DSP. In this paper, a new real-time parameter tracking algorithm is derived from three phase equation. The validity and usefulness of the proposed inductance estimation technique is verified by simulation and experimental results.

A Study on Arc Sensor for Weld Seam Tracking by Using Fuzzy Control (퍼지제어를 이용한 용접선 추적용 아크센서에 관한 연구)

  • 조시훈;김재웅
    • Journal of Welding and Joining
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    • v.13 no.1
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    • pp.156-166
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    • 1995
  • Experimental models which are able to determine the deviation between weld line and weaving center by measuring the weld current during welding were proposed for the gas metal arc welding process. The models were used for developing a weld seam tracking system which controls the weaving speed of a welding torch. However, it was revealed that the tracking result of the system is affected by the welding conditions. Thus an arc sensor system was developed by using fuzzy control approach for overcoming the difficulty of modelling the nonlinear process. The rule base and parameters of the fuzzy control system were determined on the basis of the results of experiments. This fuzzy control system has shown the successful tracking capability for the wide operating range of welding conditions.

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Research of the Unmanned Vehicle Control and Modeling for Lane Tracking (차선인식을 위한 무인자동차의 차량제어 및 모델링에 관한 연구)

  • 김상겸;임하영;김정하
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.6
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    • pp.213-221
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    • 2003
  • This paper describes a method of lane tracking by means of a vision system which includes vehicle control and modeling. Lane tracking is considered one of the important technologies in an unmanned vehicle and mobile robot system. The current position and condition of the vehicle are calculated from an image processing method by a CCD camera. We deal with lane tracking as follows. First, vehicle control is included in the road model, and lateral and longitudinal controls. Second, the image processing method deals with the lane detection method, image processing algerian, and filtering method. Finally, this paper proposes a correct method for lane detection through a vehicle test by wireless data communication.

An Algorithm for Color Object Tracking (색상변화를 갖는 객체추적 알고리즘)

  • Whoang, In-Teck;Choi, Kwang-Nam
    • Journal of Korea Multimedia Society
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    • v.10 no.7
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    • pp.827-837
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    • 2007
  • Conventional color-based object tracking using Mean Shift algorithm does not provide appropriate result when initial color distribution disappears. In this paper we propose a tracking algorithm that updates the object color sample when the color is changing. Mean Shift analysis is first used to derive the object candidate with maximum increase in density direction from current position. The color information of object is updated iteratively. The proposed algorithm achieves accurate tracking of objects when initial color samples are changed and finally disappeared. The validity of the effective approach is illustrated by the experimental results.

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Tracking Characteristics of Silicone Insulators (실리콘 절연체의 트래킹 열화특성)

  • Lee, June-Ho;Kim, Suk-Cheol;HwangBo, Seung;Ji, Won-Yeong;Han, Min-Koo
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.929-931
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    • 1998
  • The tracking characteristics of silicon rubber degraded by accelerated outdoor exposure employing a weather-o-meter have been investigated. The tracking test was performed according to IEC Publ.587 but the concentration of conductive material was two times higher than the IEC standard in order to accelerate the tracking failure. The number of large effective scintillation and the current of high voltage circuit were measured by changing two signals as voltage signals. It was fiund that the increase of exposure time resulted in the reduction of tracking resistivity except the fact that the specimens slightly degraded within 200 hours has slightly increased the duration time.

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Object Tracking Using Particle Filter with an Improved Observe Method (개선된 Observe 기법을 적용한 Particle Filter 물체 추적)

  • Cho, Hyun-Joong;Lee, Chul-Woo;Jung, Jae-Gi;Kim, Jin-Yul
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.210-212
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    • 2009
  • In object tracking based on the particle filter algorithm controlling the proper distribution of the samples is essential to accurately track the target. If the samples are spread too wide compared to the target size, the tracking accuracy may degrade as some samples can be caught by background clutters that is similar to the target. On the other hands if the samples are spread too narrow, the particle filter may fail to track the abrupt motion of the target. To solve this problem we propose an improved particle filter that adopts "re-weighting" technique at the observe step. We estimate the distribution of the weights of the current samples by its mean and variance. Then the samples are re-weighted so that the appropriate distribution of the samples in proportional to the target scale is obtained at the next select step. The proposed tracking method can avoid convergence to local mean and improve the accuracy of the estimated target state.

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The Effect of Contaminants and Surface Roughness on Tracking Aging (트랙킹 열화에 미치는 오손액과 표면거칠기의 영향)

  • Cho, H.G.;Kim, I.S.;Kang, T.P.;Ahn, M.S.;Park, Y.K.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1673-1675
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    • 1996
  • We have studied the effect of surface tension and flow rate of contaminants, wettability, frequency of applied voltage dependence of tracking breakdown. As the flow rate of contaminant is increasd, the surface resistivity is decreased, and the leakage current is increased, the time to tracking breakdown is decreased. It is found that time to tracking breakdown depends on the frequency of contaminant, that is difference of wettability. And as the frequency of applied voltage is increased, time to tracking breakdown decreased.

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Control of an above-knee prosthesis using MR damper (MR 감쇠기를 이용한 무릎 관절 의족의 제어)

  • 김정훈;오준호
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.244-244
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    • 2000
  • We proposed the above-knee prosthesis using rotary MR damper in which knee joint is semi-actively controlled by microprocessor. Dissipation torque in the knee joint can be controlled by the magnetic field which is induced by applying current to a solenoid, Tracking control of knee joint angle was tested by 3-DOF Leg simulator. The experimental results show that the proposed above-knee prosthesis system had good performance in swing phase tracking and repetitive controller in conjunction with a computed control law and PD control law, reduced RMS tracking error as the repetitions of tracking. Moreover, desired knee angle trajectory was generated based on the estimation of gait period with the gyro signal and the tracking control was performed.

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