• Title/Summary/Keyword: Common control point

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Novel Model Predictive Control Method to Eliminate Common-mode Voltage for Three-level T-type Inverters Considering Dead-time Effects

  • Wang, Xiaodong;Zou, Jianxiao;Dong, Zhenhua;Xie, Chuan;Li, Kai;Guerrero, Josep M.
    • Journal of Power Electronics
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    • v.18 no.5
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    • pp.1458-1469
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    • 2018
  • This paper proposes a novel common-mode voltage (CMV) elimination (CMV-EL) method based on model predictive control (MPC) to eliminate CMV for three-level T-type inverters (3LT2Is). In the proposed MPC method, only six medium and one zero voltage vectors (VVs) (6MV1Z) that generate zero CMV are considered as candidates to perform the MPC. Moreover, the influence of dead-time effects on the CMV of the MPC-based 6MV1Z method is investigated, and the candidate VVs are redesigned by pre-excluding the VVs that will cause CMV fluctuations during the dead time from 6MV1Z. Only three or five VVs are included to perform optimization in every control period, which can significantly reduce the computational complexity. Thus, a small control period can be implemented in the practical applications to achieve improved grid current performance. With the proposed CMV-EL method, the CMV of the $3LT^2Is$ can be effectively eliminated. In addition, the proposed CMV-EL method can balance the neutral point potentials (NPPs) and yield satisfactory performance for grid current tracking in steady and dynamic states. Simulation and experimental results are presented to verify the effectiveness of the proposed method.

A Study on the MPPT Control Algorithm and Efficiency Evaluation Method (MPPT제어 알고리즘 고찰 및 효율시험 평가법)

  • 유권종;김기현;정영석;김영석
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.2
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    • pp.164-172
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    • 2001
  • This paper describes common MPPT(Maximum Power Point Tracking) control algorithm; Constant Voltage Control, P&O(Perturbation and Observation), IncCond(Incremental Conductance), and investigated it\`s efficiency. Though simulation and efficiency evaluation, the steady/transient states characteristics and efficiency of control algorithms are analyzed respectively. Also, two-mode MPPT control to improve on the existing control algorithm. Moreover, is proposed for high efficiency this paper suggests a topology for MPPT measuring efficiency and a method of examination.

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Optimal National Coordinate System Transform Model using National Control Point Network Adjustment Results (국가지준점 망조정 성과를 활용한 최적 국가 좌표계 변환 모델 결정)

  • Song, Dong-Seob;Jang, Eun-Seok;Kim, Tae-Woo;Yun, Hong-Sic
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.6_2
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    • pp.613-623
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    • 2007
  • The main purpose of this study is to investigate the coordinate transformation based on two different systems between local geodetic datum(tokyo datum) and international geocentric datum(new Korea geodetic datum). For this purpose, three methods were used to determine seven parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. Also, we adopted multiple regression equation method to convert from Tokyo datum to KTRF. We used 935 control points as a common points and applied gross error analysis for detecting the outlier among those control points. The coordinate transformation was carried out using similarity transformation applied the obtained seven parameters and the precision of transformed coordinate was evaluated about 9,917 third or forth order control points. From these results, it was found that Bursa-Wolf model and Molodensky-Badekas model are more suitable than other for the determination of transformation parameters in Korea. And, transforming accuracy using MRE is lower than other similarity transformation model.

The Life Cycle of the Rendezvous Problem of Cognitive Radio Ad Hoc Networks: A Survey

  • Htike, Zaw;Hong, Choong Seon;Lee, Sungwon
    • Journal of Computing Science and Engineering
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    • v.7 no.2
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    • pp.81-88
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    • 2013
  • In cognitive radio or dynamic spectrum access networks, a rendezvous represents meeting two or more users on a common channel, and negotiating to establish data communication. The rendezvous problem is one of the most challenging tasks in cognitive radio ad hoc networks. Generally, this problem is simplified by using two well-known mechanisms: the first uses a predefined common control channel, while the second employs a channel hopping procedure. Yet, these two mechanisms form a life cycle, when they simplify the rendezvous problem in cognitive radio networks. The main purpose of this paper is to point out how and why this cycle forms.

Common Cause Failure Problems in Ultra-High Reliability Systems-A View Point on Common Cause Internal Effects and Statistical Principles (초신뢰성 시스팀에서의 공통원인 실패문제-공통원인의 내부적 효과 및 통계학적 원리의 관점에서)

  • Park, P.;Ko, K.H.;Kim, C.S.;Kim, H.K.;Oh, H.S.
    • Electronics and Telecommunications Trends
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    • v.8 no.3
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    • pp.39-52
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    • 1993
  • This study involves a Common Cause Failure (CCF) problem on the ultra-high reliability required system development such as war game operations, nuclear power control, air traffic control, space shuttle missions, and large scale network communication system. The system situation problems are defined according to CCF, reliability and system fault identifications for the development cast verifications in the multi-version redundant software system. Then, CCF analysis of redundant system, system principles and statistical dependence are also described. This validation oh the CCF in the human software interaction system will notify software engineers to conceive what really is CCF contribution factor, not only the internal but the external ones.

Pulse-Width Modulation Strategy for Common Mode Voltage Elimination with Reduced Common Mode Voltage Spikes in Multilevel Inverters with Extension to Over-Modulation Mode

  • Pham, Khoa-Dang;Nguyen, Nho-Van
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.727-743
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    • 2019
  • This paper presents a pulse-width modulation strategy to eliminate the common mode voltage (CMV) with reduced CMV spikes in multilevel inverters since a high CMV magnitude and its fast variations dv/dt result in bearing failure of motors, overvoltage at motor terminals, and electromagnetic interference (EMI). The proposed method only utilizes the zero CMV states in a space vector diagram and it is implemented by a carrier-based pulse-width modulation (CBPWM) method. This method is generalized for odd number levels of inverters including neutral-point-clamped (NPC) and cascaded H-bridge inverters. Then it is extended to the over-modulation mode. The over-modulation mode is implemented by using the two-limit trajectory principle to maintain linear control and to avoid look-up tables. Even though the CMV is eliminated, CMV spikes that can cause EMI and bearing current problems still exist due to the deadtime effect. As a result, the deadtime effect is analyzed. By taking the deadtime effect into consideration, the proposed method is capable of reducing CMV spikes. Simulation and experimental results verify the effectiveness of the proposed strategy.

How Compliant are Tobacco Vendors to India's Tobacco Control Legislation on Ban of Advertisments at Point of Sale? A Three Jurisdictions Review

  • Goel, Sonu;Kumar, Ravinder;Lal, Pranay;Tripathi, J.P.;Singh, Rana J.;Rathinam, Arul;Christian, Anant
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.24
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    • pp.10637-10642
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    • 2015
  • Background: Section 5 of India's tobacco control legislation "Cigarettes and Other Tobacco Products Act (COTPA), 2003"comprehensively prohibits all kinds of tobacco advertisement, promotion and sponsorship (TAPS), but permits advertisments at the point-of-sale (POS) under certain conditions. This provision has been exploited by the tobacco companies to promote their products. Objective: To measure compliance with the provisions of Section 5 of Indian tobacco control legislation (COTPA, 2003) at point of sale. Materials and Methods: A cross-sectional survey using an observation checklist was conducted in 1860 POS across three jurisdictions (Chennai city, District Vadodara and District Mohali) in India. Results: The most common mode of advertisement of tobacco products was product showcasing (51.1%), followed by dangles (49.6%), stickers (33.8%) and boards (27.1%). More than one fourth of POS were found violating legal provisions for displaying advertisement boards in one or other forms (oversized, extended to full body lenth of POS, displayed brandname/packshot and promotional messages). Advertisement boards (16.3%) without health warnings were also found and wherever found, more than 90% health warning were not as per the specification in respect to size, font and background color. Conclusions: Point of sale advertising is aggressively used by the tobacco industry to promote their products. There is an urgent need of effective implementation of a comprehensive ban on tobacco product advertisement, promotion and sponsorship at point of sale.

PID Control of Unstable Processes with Time Delay (시간지연을 갖는 불안정한 시스템의 PID 제어)

  • Lee, Soo-Lyong;Lee, Yun-Hyung;Ahn, Jong-Kap;Son, Jung-Ki;Ryu, Ki-Tak;So, Myung-Ok
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.5
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    • pp.721-728
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    • 2009
  • PID control is widely used to control stable processes, however, PID control for unstable processes is less common. In this paper, systematic tuning methods are derived to tune the PID controller for unstable FOPTD(Forst Order Plus Time Delay) processes. The proposed PID controllers for set-point tracking and disturbance rejection problem are tuned based on minimizing the performance indexes (IAE, ISE, ITAE) using a real-coded genetic algorithm. Simulation example is given to illustrate the set-point tracking and disturbance rejection performance of the proposed method.

Firing Angle Control of Soft Starter for Reduction of Inrush Current during Induction Generator to Gird (유도발전기 계통 연계시 돌입전류 저감을 위한 소프트 스타터 점호각 제어)

  • Kwon Tae-Hwa;Song Seung-Ho
    • Proceedings of the KIPE Conference
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    • 2003.11a
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    • pp.230-233
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    • 2003
  • Simulation model of induction type fixed speed wind power generator is developed. It is shown that the peak value of inrush current during start up changes according to the firing angle control strategy of soft starter. New proposed firing angle control scheme showed $25\%$ of reduction of peak current which results in smaller drop of gird voltage at the point of common coupling during start up.

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Experimental study on control of selective-collective elevator drive system using microcomputer (마이크로콤퓨터에 의한 방향성 승합 엘리베이터 운전 시스템 제어의 실험적 연구)

  • 황희륭;이영욱;김수운
    • 전기의세계
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    • v.30 no.1
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    • pp.55-63
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    • 1981
  • This paper deals with the drive contrl of common elevator systems which may be realized with .mu.p-controlled selective-collective elevator systems. Incorporation on non-contact point circuits instead of electromagnetic relays in such an elevator system results in miniaturization of complicated hardware controllers currently being used. The drive control method is implemented by software programming. The important features are not only technical advantages such as higher performance, high speed data processing and more improved reliability, but also lower cost as compared with the conventional elevator drive control units equipped with a number of sequential electromagnetic relays and even more recent static IC logic circuits.

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