Three-Phase Magnitude Detection Based on Decoupling Positive and Negative Sequences of Double D-Q Transformation

2013 ◽  
Vol 765-767 ◽  
pp. 2101-2104
Author(s):  
Xiao Ying Zhang ◽  
Zheng Jiang ◽  
Zhong Jian Zhou
Keyword(s):  
Time Lapse ◽  
Fundamental Wave ◽  
The Novel ◽  
Negative Sequence ◽  
Synchronous Reference Frame ◽  
Three Phase ◽  
Harmonic Pollution ◽  
Sequence Components ◽  
Novel Method ◽  
The Impact

This paper introduces T/4 time-lapse elimination detection, a novel method of detecting three-phase magnitude based on double d-q synchronous reference frame, functioning in decoupling positive and negative sequences of fundamental wave. When the voltage (or current) fundamental positive and negative sequence components are separated, their magnitudes can be detected respectively, so it is effective to restrain the impact on detection precision from negative sequence component. To verify the performance of this novel method, simulation experiments like transient response under normal grid condition and dynamic response under three-phase unbalance with harmonic pollution condition is finished. The results indicate that the novel method obtains a high precision of measure and a better dynamic property and has advantages on preventing harmonic propagation compared with T/16 time-lapse elimination detection method. Thus it can be wildly applied in three-phase power electronic devices.

scholarly journals Modeling of three-phase electric motor operation by the MATLAB system with deteriorated power quality in the 0.38 kV distribution networks

2018 ◽  
Vol 58 ◽  
pp. 03016 ◽  
Author(s):  
I.V Naumov ◽  
N.V. Savina ◽  
M.V. Shevchenko
Keyword(s):  
Induction Motor ◽  
Power Quality ◽  
Electric Motor ◽  
Distribution Networks ◽  
Negative Sequence ◽  
Operation Modes ◽  
Three Phase ◽  
Sequence Components ◽  
Motor Operation ◽  
The Impact

One of the main operation modes that characterizes power quality in distribution networks is asymmetry of three-phase voltage system. Operation of an induction motor (IM) with disturbed voltage symmetry in the supply network can not be considered as a rated one. The system of voltages applied to the stator winding of IM under these conditions contains positive- and negative-sequence components. This worsens the performance characteristics of IM essentially. In order to balance the 0.38 kV network operation and enhance the efficiency of the three-phase electric motor operation it is suggested to use a special balancing unit (BU) that minimizes the negative-sequence components of current and voltage. The operation modes of the obtained system “supply source – induction motor – balancing unit” are simulated within the MATLAB software package of applied programs, which allows one to assess the impact of low quality of power on the operating characteristics of the electric motor and the efficiency of the balancing unit to increase the “durability” of the motor under the asymmetrical power consumption.

scholarly journals AIRank: Author Impact Ranking through Positions in Collaboration Networks

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Jun Zhang ◽  
Yan Hu ◽  
Zhaolong Ning ◽  
Amr Tolba ◽  
Elsayed Elashkar ◽  
...  
Keyword(s):  
Impact Evaluation ◽  
The Novel ◽  
Interesting Phenomenon ◽  
Scientific Impact ◽  
Academic Networks ◽  
Novel Method ◽  
Academic Information ◽  
The Impact ◽  
In Virtue Of ◽  
Scientific Collaborations

Citation is a universally acknowledged way for scientific impact evaluation. However, due to its easy manipulability, simply relying on citation cannot objectively reflect the actual impact of scholars. Instead of citation, we utilize the academic networks, in virtue of their available and abundant academic information, to evaluate the scientific impact of scholars in this paper. Through the collaboration among scholars in academic networks, we notice an interesting phenomenon that scholars in some special positions can access more kinds of information and connect researchers from different groups to promote the scientific collaborations. However, this important fact is generally ignored by the existing approaches. Motivated by the observations above, we propose the novel method AIRank to evaluate the scientific impact of scholars. Our method not only considers the impact of scholars through the mutual reinforcement process in heterogeneous academic networks, but also integrates the structural holes theory and information entropy theory to depict the benefit that scholars obtain via their positions in the network. The experimental results demonstrate the effectiveness of AIRank in evaluating the impact of scholars more comprehensively and finding more top ranking scholars with interdisciplinary nature.

Unbalanced Control Strategy for DFIG Used in Wind Turbines

2013 ◽  
Vol 805-806 ◽  
pp. 430-435
Author(s):  
Chang Xi Huang ◽  
Shu Ying Yang ◽  
Liu Wei Chen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Grid ◽  
Current Control ◽  
Doubly Fed Induction Generator ◽  
Test Bed ◽  
Negative Sequence ◽  
Synchronous Reference Frame ◽  
Sequence Components ◽  
Doubly Fed

Unbalanced input voltages would make doubly fed induction generator (DFIG)-based wind turbine operating performance deteriorate, such as shaft tremble, temperature increasing, and so on, even make it cut out of the power grid. Meanwhile, without proper control the power ripples generated from wind turbines may further aggravate power grid. Considering the unbalanced conditions, DFIG was modeled in dual synchronous reference frame (SRF), namely the positive one and the negative one, based on which the dual PI current controllers were designed. To implement the dual current control, the sensing variables were divided into positive and negative sequence components, which were controlled in positive and negative SRF respectively. At the same time, to synchronize with the positive and negative sequence voltage components, a phase latch loop (PLL) control was designed. Experimental results on 11kW DFIG wind turbine test bed validated the designed control system.

Novel Assessment Method for Support Conditions of Concrete Pavement under Traffic Loads using Distributed Optical Sensing Technology

2020 ◽  
Vol 2674 (4) ◽  
pp. 42-56
Author(s):  
Mengyuan Zeng ◽  
Difei Wu ◽  
Hongduo Zhao ◽  
Hui Chen ◽  
Zeying Bian
Keyword(s):  
Frequency Spectrum ◽  
Assessment Method ◽  
Concrete Pavement ◽  
The Novel ◽  
Moving Loads ◽  
Traffic Loads ◽  
Sensing Technology ◽  
Novel Method ◽  
Support Conditions ◽  
The Impact

Loss of support is a common concrete pavement distress that may affect pavement performance directly. Previous studies have proved that vibration-based methods have the potential for detecting loss of support in a more efficient way but this is limited by loading conditions. This paper presents a further study concerning the effects of moving loads and proposes a novel method for assessing support conditions of concrete pavement under traffic loads using distributed optical vibration sensing technology. First, finite element analysis and laboratory tests were conducted to investigate the impact of loss of support on pavement vibration induced by moving loads with reference to the frequency spectrum. The impact of loading conditions, including loading position and speed, was also studied using the same methods. The results indicate that both loss of support and loading characteristics have a considerable effect on the distribution of the frequency spectrum. It is proved that weighted frequency can be utilized for assessment of support conditions under a specific loading condition. It is suggested the loading position needs to be close to the measurement point (distance < 0.3 m) to obtain stable and reliable data for assessment of support conditions. In addition, the loading speed should be adequately fast and steady (4 to 5 m/s) to ensure the significance of the effect of loss of support. A field test was conducted in an airport, and the novel assessment method was validated by comparing it with a conventional deflection-based method. The novel method proved to be reliable for implementation in practice.

scholarly journals A Novel Fast Voltage Sequence Component Detector of Unbalanced Three-Phase System

2018 ◽  
Vol 173 ◽  
pp. 01036
Author(s):  
Baohong Jiang ◽  
Xinian Li
Keyword(s):  
Reference Frame ◽  
Traditional Method ◽  
Phase System ◽  
Detection Time ◽  
Continuous Processing ◽  
Synchronous Reference Frame ◽  
Three Phase ◽  
Rotating Reference Frame ◽  
Sequence Components ◽  
Simulation Results

The fast and accurate voltage sequence component detection of unbalanced three-phase system is of major importance for the industrial continuous processing. The traditional method is to calculate the voltage in dq synchronous reference frame. This results in low order harmonics and long detection time. A novel fast voltage sequence components detector is proposed in this paper. It is to calculate the sequence component projection on dq rotating reference frame with h times the fundamental angular velocity. Simulation results demonstrate the validity of the algorithm.

Experimental Investigation on the Impact of Distorted Signal on Synthetic Jet

2016 ◽  
Vol 831 ◽  
pp. 104-111
Author(s):  
Paweł Gil
Keyword(s):  
Input Signal ◽  
Average Velocity ◽  
Fluid Velocity ◽  
Synthetic Jet ◽  
The Novel ◽  
Synthetic Jet Actuator ◽  
Negative Effect ◽  
Novel Method ◽  
Conventional Cooling ◽  
The Impact

Effective techniques for cooling electronic devices must deal with increasing heat loads associated with higher heat flux density. Many conventional cooling techniques like fan are reaching the limits of their effectiveness and shape. The novel method of heat transfer enhancement is synthetic jet. In this paper experimental results are presented. Synthetic jet actuator consist of STX 6.5 inch speaker installed in metacrylate chamber with circular orifice. The actuator was powered with signal from amplifier. The signal consist of basic sinusoidal function and THD noise added with some amplitude. The root mean square of signal voltage was constant 4V. The properties of synthetic jet were measured using constant temperature thermo-anemometer. Instantaneous velocity of air was measured in the orifice center and compared with input signal. Additional RMS and average velocity of air were measured. Measurement revealed that input signal of synthetic jet generator can contain some noise without effect on RMS and average velocity of air in the orifice. The THD less than 1% does not cause negative effect on synthetic jet fluid velocity.

The Optimization of Sintering Process for Alumina Extraction from Fly Ash

2014 ◽  
Vol 878 ◽  
pp. 264-270 ◽  
Author(s):  
Xiao Huan Wang ◽  
Bao Dong Wang ◽  
Yong Feng Xiao ◽  
Xiao Ting Liu ◽  
Li Jun Zhao ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Fly Ash ◽  
Six Sigma ◽  
Sintering Temperature ◽  
High Alumina ◽  
The Novel ◽  
Sintering Process ◽  
Novel Method ◽  
The Impact ◽  
Six Sigma Approach

The objective of paper is to optimize the variables of the sintering process with the six sigma philosophy. The impact of sintering temperature, Ca ratio, Na ratio and reaction time on the alumina reaching rate were primarily studied. In the research, a novel method was adopted to efficiently recover alumina and silica from high-alumina fly ash, and the response surface methodology of six sigma approach was also implemented to analysis the results obtained by the experiments. There is great significance to optimize sintering process for the industrialization of the novel method. Amount of energy consumption will be reduced in the production.

scholarly journals Determining Air Traffic Complexity – Challenges and Future Development

2020 ◽  
Vol 32 (4) ◽  
pp. 475-485
Author(s):  
Bruno Antulov-Fantulin ◽  
Biljana Juričić ◽  
Tomislav Radišić ◽  
Cem Çetek
Keyword(s):  
Future Development ◽  
Relevant Literature ◽  
Air Traffic ◽  
The Novel ◽  
Air Traffic Controller ◽  
Air Traffic Controllers ◽  
Static Images ◽  
Preliminary Communication ◽  
Novel Method ◽  
The Impact

Air traffic complexity is one of the main drivers of the air traffic controllers’ workload. With the forecasted increase of air traffic, the impact of complexity on the controllers' workload will be even more pronounced in the coming years. The existing models and methods for determining air traffic complexity have drawbacks and issues which are still an unsolved challenge. In this paper, an overview is given of the most relevant literature on air traffic complexity and improvements that can be done in this field. The existing issues have been tackled and new solutions have been given on how to improve the determination of air traffic complexity. A preliminary communication is given on the future development of a novel method for determining air traffic complexity with the aim of designing a new air traffic complexity model based on air traffic controller tasks. The novel method uses new solutions, such as air traffic controller tasks defined on pre-conflict resolution parameters, experiment design, static images of traffic situations and generic airspace to improve the existing air traffic complexity models.

scholarly journals Induction Motor Stator Interturn Short Circuit Fault Detection in Accordance with Line Current Sequence Components Using Artificial Neural Network

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Gayatridevi Rajamany ◽  
Sekar Srinivasan ◽  
Krishnan Rajamany ◽  
Ramesh K. Natarajan
Keyword(s):  
Neural Network ◽  
Fault Detection ◽  
Induction Motor ◽  
Short Circuit ◽  
Positive Sequence ◽  
Negative Sequence ◽  
Three Phase ◽  
Sequence Components ◽  
Negative Sequence Current ◽  
Short Circuit Fault

The intention of fault detection is to detect the fault at the beginning stage and shut off the machine immediately to avoid motor failure due to the large fault current. In this work, an online fault diagnosis of stator interturn fault of a three-phase induction motor based on the concept of symmetrical components is presented. A mathematical model of an induction motor with turn fault is developed to interpret machine performance under fault. A Simulink model of a three-phase induction motor with stator interturn fault is created for extraction of sequence components of current and voltage. The negative sequence current can provide a decisive and rapid monitoring technique to detect stator interturn short circuit fault of the induction motor. The per unit change in negative sequence current with positive sequence current is the main fault indicator which is imported to neural network architecture. The output of the feedforward backpropagation neural network classifies the short circuit fault level of stator winding.

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