Rapid parameter identification and control of an induction machine

2018 ◽  
Vol 37 (5) ◽  
pp. 1678-1688 ◽  
Author(s):  
Martin Marco Nell ◽  
Georg von Pfingsten ◽  
Kay Hameyer
Keyword(s):  
Significant Contribution ◽  
Induction Machine ◽  
Evolutionary Strategy ◽  
Control Technique ◽  
Machine Parameter ◽  
Content Type ◽  
Rotor Resistance ◽  
Ohmic Losses ◽  
Rotor Flux ◽  
And Control

Purpose Traction applications, e.g. the IMs are mainly operated by field-oriented control (FOC). This control technique requires an accurate knowledge of the machine’s parameters, such as the main inductance, the leakage inductances and the stator and rotor resistance. The accuracy of the parameters influences the precision of the calculated rotor flux and the rotor flux angle and the decoupling of the machine’s equations into the direct and quadrature coordinate system (dq-components). Furthermore, the parameters are used to configure the controllers of the FOC system and therefore influence the dynamic behavior and stability of the control. Design/methodology/approach In this paper, three different methods to calculate the machine’s parameters, in an automated and rapid procedure with minimal measuring expenditure, are analyzed and compared. Moreover, a method to configure a control that reduces the overall Ohmic losses of the machine in every torque speed operation point is presented. The machine control is configured only with the identified machine parameter. Findings Simulations and test bench measurements show that the evolutionary strategy is able to identify the electrical parameters of the machine in less time and with low error. Moreover, the controller is able to control the torque of the machine with a deviation of less than 2 per cent. Originality/value The most significant contribution of the research is the potential to identify the machine parameter of an induction motor and to configure an accurate control with these parameters.

A New Induction Motor Adaptive Robust Vector Control based on Backstepping

2017 ◽  
Vol 7 (4) ◽  
pp. 1983 ◽  
Author(s):  
Mhamed Madark ◽  
A. Ba-Razzouk ◽  
E. Abdelmounim ◽  
M.El Malah
Keyword(s):  
Vector Control ◽  
Time Constant ◽  
Induction Machine ◽  
Open Loop ◽  
Control Technique ◽  
Load Torque ◽  
Novel Approach ◽  
Rotor Flux ◽  
On Line ◽  
Simulation Results

<p>In this paper, a novel approach to nonlinear control of induction machine, recursive on-line estimation of rotor time constant and load torque are developed. The proposed strategy combines Integrated Backstepping and Indirect Field Oriented Controls. The proposed approach is used to design controllers for the rotor flux and speed, estimate the values of rotor time constant and load torque and track their changes on-line. An open loop estimator is used to estimate the rotor flux. Simulation results are presented which demonstrate the effectiveness of the control technique and on-line estimation.</p>

Adaptive PI Control Strategy for a Self-Excited Induction Generator Driven by a Variable Speed Wind Turbine

2016 ◽  
Vol 26 (02) ◽  
pp. 1750024 ◽  
Author(s):  
Godpromesse Kenne ◽  
Clotaire Thierry Sanjong ◽  
Eustace Mbaka Nfah
Keyword(s):  
Wind Speed ◽  
Control Strategy ◽  
Control Technique ◽  
Induction Generator ◽  
Speed Profile ◽  
Wind Speed Profile ◽  
Proportional Integral ◽  
Rotor Resistance ◽  
Rotor Flux ◽  
Variable Wind

In this paper, an adaptive proportional-integral (API) control strategy is developed to extract the maximum power from a variable wind speed turbine and to regulate the DC-link voltage, rotor flux and AC load voltage in a three-phase grid-connected self-excited induction generator (SEIG) system. The resulting controller associated to the flux-oriented control technique can be easily implemented in practice since finite time estimators for the unknown time-varying rotor resistance, rotor flux (nonmeasurable signal) and stator electrical angular position required for the online implementation of the proposed algorithm are provided. Comparative results with a conventional nonadaptive proportional-integral regulator have shown the superiority of the proposed strategy in terms of robustness with respect to online variation of the rotor resistance (up to 100%) and large varying load condition. The computing results are obtained using relatively low wind speed profile. Thus, the generating system with the proposed control strategy is suitable for variable wind speed turbine installation for grid-connected and remote-area power supply where the wind speed profile is relatively low.

Learning analytics: where information science and the learning sciences meet

2019 ◽  
Vol 120 (1/2) ◽  
pp. 59-73 ◽  
Author(s):  
Stephanie Danell Teasley
Keyword(s):  
Learning Analytics ◽  
Design Methodology ◽  
Significant Contribution ◽  
Information Science ◽  
Research Area ◽  
Learning Sciences ◽  
Digital Tools ◽  
Content Type ◽  
Working Together ◽  
Everyday Learning

Purpose The explosive growth in the number of digital tools utilized in everyday learning activities generates data at an unprecedented scale, providing exciting challenges that cross scholarly communities. This paper aims to provide an overview of learning analytics (LA) with the aim of helping members of the information and learning sciences communities understand how educational Big Data is relevant to their research agendas and how they can contribute to this growing new field. Design/methodology/approach Highlighting shared values and issues illustrates why LA is the perfect meeting ground for information and the learning sciences, and suggests how by working together effective LA tools can be designed to innovate education. Findings Analytics-driven performance dashboards are offered as a specific example of one research area where information and learning scientists can make a significant contribution to LA research. Recent reviews of existing dashboard studies point to a dearth of evaluation with regard to either theory or outcomes. Here, the relevant expertise from researchers in both the learning sciences and information science is offered as an important opportunity to improve the design and evaluation of student-facing dashboards. Originality/value This paper outlines important ties between three scholarly communities to illustrate how their combined research expertise is crucial to advancing how we understand learning and for developing LA-based interventions that meet the values that we all share.

Antecedents and consequences of replacing international independent intermediaries

2014 ◽  
Vol 26 (3) ◽  
pp. 218-237
Author(s):  
Erik B. Nes
Keyword(s):  
Longitudinal Design ◽  
Operation Mode ◽  
Content Type ◽  
Performance Variables ◽  
Direct Sales ◽  
Home Based ◽  
Process Theories ◽  
Antecedents And Consequences ◽  
Communication Control ◽  
And Control

Purpose – What characterizes the relationships with intermediaries that are soon to be replaced, and are the replacements successful? The paper aims to discuss these issues. Design/methodology/approach – The study applies a longitudinal design. The paper conducted a survey among a sample of exporters concerning their relationships with independent intermediaries in terms of trust, commitment, communication, control and two performance variables; financial performance and strategic goal achievement. Five years thereafter the author contacted the same companies again and questioned which independent intermediaries had been replaced in the period. The author then compared the replaced intermediaries with the extended intermediaries before they were replaced and analysed changes in the evaluations of the relationships and of the performance after the replacement. Findings – The relationships with terminated intermediaries that were replaced by sales subsidiary or home-based direct sales were characterized having higher trust, communication and control than extended relationships before replacement. While it may be surprising that these quite successful relationships were terminated, this is in line with internationalization process theories. The replacements, both intermediaries that were replaced by other intermediaries and by sales subsidiary/home-based direct sales, were highly successful in terms of improvement in performance and behavioural relationship variables. Research limitations/implications – The empirical findings are limited by the sample and by data collection from the principal only in the dyadic relations. Practical implications – International independent intermediaries should analyse the likelihood of being replaced by the principal because the relationship or the performance is unsatisfactory, but also because of satisfactory evaluations. Terminations of satisfactory relationships tend to be accompanied by change in operation mode to internal organization. The independent intermediary should in such cases build a defence structure against unwanted termination and/or prepare for buyout. The success of the replacements suggests that international marketers benefit from being proactive in replacing intermediaries with new intermediaries or with a hierarchal entry mode. Originality/value – This is the first study that applies most of these variables from interorganizational relations theory in the study of international independent intermediary replacements. It is also the first to give insight into the consequences of intermediary terminations.

scholarly journals Impact of Substratum Surface on Microbial Community Structure and Treatment Performance in Biological Aerated Filters

2013 ◽  
Vol 80 (1) ◽  
pp. 177-183 ◽  
Author(s):  
Lavane Kim ◽  
Eulyn Pagaling ◽  
Yi Y. Zuo ◽  
Tao Yan
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Bacterial Species ◽  
Community Analysis ◽  
Microbial Community Analysis ◽  
Rrna Gene ◽  
Content Type ◽  
Property Change ◽  
And Control ◽  
Start Ups

ABSTRACTThe impact of substratum surface property change on biofilm community structure was investigated using laboratory biological aerated filter (BAF) reactors and molecular microbial community analysis. Two substratum surfaces that differed in surface properties were created via surface coating and used to develop biofilms in test (modified surface) and control (original surface) BAF reactors. Microbial community analysis by 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis (DGGE) showed that the surface property change consistently resulted in distinct profiles of microbial populations during replicate reactor start-ups. Pyrosequencing of the bar-coded 16S rRNA gene amplicons surveyed more than 90% of the microbial diversity in the microbial communities and identified 72 unique bacterial species within 19 bacterial orders. Among the 19 orders of bacteria detected,BurkholderialesandRhodocyclalesof theBetaproteobacteriaclass were numerically dominant and accounted for 90.5 to 97.4% of the sequence reads, and their relative abundances in the test and control BAF reactors were different in consistent patterns during the two reactor start-ups. Three of the five dominant bacterial species also showed consistent relative abundance changes between the test and control BAF reactors. The different biofilm microbial communities led to different treatment efficiencies, with consistently higher total organic carbon (TOC) removal in the test reactor than in the control reactor. Further understanding of how surface properties affect biofilm microbial communities and functional performance would enable the rational design of new generations of substrata for the improvement of biofilm-based biological treatment processes.

Modeling and simulation of saturated double rotor induction machine

2018 ◽  
Vol 37 (3) ◽  
pp. 1139-1165
Author(s):  
Koosha Choobdari Omran ◽  
Ali Mosallanejad
Keyword(s):  
Temperature Effects ◽  
Power Efficiency ◽  
Reactive Power ◽  
Induction Machine ◽  
Transient Behavior ◽  
State Equations ◽  
Content Type ◽  
Proposed Model ◽  
The Difference ◽  
Park Transformation

Purpose Double rotor induction machine (DRIM) is a particular type of induction machine (IM) that has been introduced to improve the parameters of the conventional IM. The purpose of this study is to propose a dynamic model of the DRIM under saturated and unsaturated conditions by using the equations obtained in this paper. Also, skin and temperature effects are considered in this model. Design/methodology/approach First, the DRIM structure and its performance will be briefly reviewed. Then, to realize the DRIM model, the mathematical equations of the electrical and mechanical part of the DRIM will be presented by state equations in the q-d axis by using the Park transformation. In this paper, the magnetizing fluxes saturation is included in the DRIM model by considering the difference between the amplitudes of the unsaturated and saturated magnetizing fluxes. The skin and temperature effects are also considered in this model by correcting the rotor and stator resistances values during operation. Findings To evaluate the effects of the saturation and skin effects on DRIM performance and validate the model, the machine is simulated with/without consideration of saturation and skin effects by the proposed model. Then, the results, including torque, speed, stator and rotor currents, active and reactive power, efficiency, power factor and torque-speed characteristic, are compared. In addition, the performance of the DRIM has been investigated at different speed conditions and load variations. The proposed model is developed in Matlab/Simulink for the sake of validation. Originality/value This paper presents an understandable model of DRIM with and without saturation, which can be used to analyze the steady-state and transient behavior of the motor in different situations.

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