scholarly journals Stability and Performance Analysis of Electrodynamic Thrust Bearings

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 11 ◽  
Author(s):  
Joachim Van Verdeghem ◽  
Virginie Kluyskens ◽  
Bruno Dehez
Keyword(s):  
Performance Criteria ◽  
Axial Stiffness ◽  
Minimal Amount ◽  
Dynamical Models ◽  
Thrust Bearings ◽  
Detent Force ◽  
Linear State ◽  
And Performance ◽  
The Stability

Electrodynamic thrust bearings (EDTBs) provide contactless rotor axial suspension through electromagnetic forces solely leaning on passive phenomena. Lately, linear state-space equations representing their quasi-static and dynamic behaviours have been developed and validated experimentally. However, to date, the exploitation of these models has been restricted to basic investigations regarding the stiffness and the rotational losses as well as qualitative stability analyses, thus not allowing us to objectively compare the intrinsic qualities of EDTBs. In this context, the present paper introduces four performance criteria directly related to the axial stiffness, the bearing energy efficiency and the minimal amount of external damping required to stabilise the thrust bearing. In addition, the stability is thoroughly examined via analytical developments based on these dynamical models. This notably leads to static and dynamic conditions that ensure the stability at a specific rotor spin speed. The resulting stable speed ranges are studied and their dependence to the axial external stiffness as well as the external non-rotating damping are analysed. Finally, a case study comparing three topologies through these performance criteria underlines that back irons fixed to the windings are not advantageous due to the significant detent force.

Dynamic Analysis and Stability Improvement Concerning the Integration of Wind Farms Kurdistan Electric Network Case Study

2011 ◽  
pp. 198-219 ◽  
Author(s):  
Mohammad Saleh ◽  
Hassan Bevrani
Keyword(s):  
Wind Power ◽  
Dynamic Models ◽  
Wind Farms ◽  
Integrated System ◽  
Electric Network ◽  
Control Approach ◽  
Control Loops ◽  
And Performance ◽  
The Stability

This chapter presents an overview of key issues and technical challenges in a regional electric network, following the integration of a considerable amount of wind power. A brief survey on wind power system, the present status of wind energy worldwide, common dynamic models, and control loops for wind turbines are given. In this chapter, the Kurdistan electric network in the Northwest part of Iran is introduced as a case study system, and an analytical approach is conducted to evaluate the potential of wind power installation, overall capacity estimation, and economic issues, based on the practical data. Then, the impact of high penetration wind power on the system dynamic and performance for various wind turbine technologies is presented. The stability of integrated system is analyzed, and the need for revising of conventional controls and performance standards is emphasized. Finally, a STATCOM-based control approach is addressed to improve the system stability.

A multi-model control of nonlinear systems: A cascade decoupled design procedure based on stability and performance

2019 ◽  
Vol 42 (7) ◽  
pp. 1271-1280 ◽  
Author(s):  
Mahdi Ahmadi ◽  
Pouya Rikhtehgar ◽  
Mohammad Haeri
Keyword(s):  
Design Procedure ◽  
Performance Criteria ◽  
Gap Metric ◽  
Redundancy Problem ◽  
Model Control ◽  
Cascade Structure ◽  
Independent Cascade ◽  
And Performance ◽  
Model Redundancy ◽  
The Stability

Recently, the multi-model controllers design was proposed in the literature based on integrating of the stability and performance criteria. Although these methods overcome the redundancy problem, the decomposition step is very complex and time consuming. In this paper, a cascade design of multi-model control is presented that is made from two sequential steps. In the first step, the nonlinear system is decomposed into a set of linear subsystems by just considering the stability criterion. In this step, the gap metric is used as a smart tool to measure the distance between linear subsystems. While the closed-loop stability is gained through the first step, the performance is improved in the second step by adding internal model controllers in a cascade structure. Therefore, the proposed idea supports designing a multi-model controller in a simple way by integrating the stability and performance criteria in two independent cascade steps. As a result, the proposed method avoids the model redundancy problem, has a simple structure, guarantees the robust stability, and improves the performance. Two nonlinear chemical processes are simulated to evaluate the proposed multi-model controller approach.

Interorganizational Networks and Open Innovation Environments

2011 ◽  
Vol 12 (4) ◽  
pp. 227-237 ◽  
Author(s):  
Pablo Munoz ◽  
Lucy Lu
Keyword(s):  
Open Innovation ◽  
Interorganizational Networks ◽  
Innovation Network ◽  
Internal Dynamics ◽  
Open Environment ◽  
Critical Issues ◽  
And Performance ◽  
The Stability

This paper examines the formation, structuring and internal dynamics of networks in an open innovation environment. Based on a case study conducted at the Creapolis Innovation Centre in Spain, it highlights the significance of several paradoxes which emerge from the interaction between organizations that share an open environment. These paradoxes have been shown to compromise the stability and performance of an effective innovation network and to represent a double-edged sword that may both facilitate and constrain the development of the innovative capacities of firms. This paper stresses the importance of a deeper understanding of such critical issues, and suggests mechanisms for creating and facilitating an appropriate and effective open innovation environment, in which knowledge is shared and exchanged between innovation actors.

scholarly journals Equity in Sharing the Potential Benefits of REDD+ in

2016 ◽  
Vol 13 (1) ◽  
pp. 20-29
Author(s):  
Doma Tshering Sherpa ◽  
Ann Brower
Keyword(s):  
Carbon Emissions ◽  
Forest Degradation ◽  
Performance Criteria ◽  
Community Forests ◽  
Efficiency And Effectiveness ◽  
Potential Benefits ◽  
And Performance ◽  
Definition Of ◽  
The Vertical Distribution

Reducing Emissions from Deforestation and Forest Degradation (REDD+) is an incentive based climate change mitigation measure that focuses on reducing carbon emissions by rewarding communities’ efforts in the conservation, sustainable management of forests and enhancement of carbon stocks. Assuming REDD+ revenues are generated, there is a question about how the benefits should be distributed. This paper uses the 3Es (Effectiveness, Efficiency and Equity) criteria in sharing the benefits of REDD+ to examine a case study in one of Nepal’s REDD+ pilot projects implemented in community forests. While concerns about equity in REDD+ are getting attention worldwide, the literature is not clear on which principle of 3Es should be given priority to achieve overall effectiveness in reducing the carbon emissions. Our research finds that equity should be prioritised to achieve efficiency and effectiveness of REDD+. Further, we find distributive equity to be the most important. Distributive equity is understood in three different ways in Nepal: rights, needs, and performance. But there is a debate on which equity should be given priority. The issues of needs vs. performance in determining what is equitable should be solved by the formulation of guidelines for how benefits should be shared at two levels in Nepal. First, the vertical distribution of benefits should be based on the ownership of carbon benefits and performance criteria. Second, at the community level, the community itself should determine the form of horizontal benefit-distribution, based on its definition of needs.Journal of Forest and Livelihood 13(1) May, 2015, Page : 20-29

Theoretizing A New Sustainable Business Event: Extension of Mair and Jago Model

2015 ◽  
Vol 3 (2) ◽  
pp. 55
Author(s):  
Norol Hamiza Zamzuri ◽  
Khairil Wahidin Awang ◽  
Yuhanis Abdul Aziz ◽  
Zaiton Samdin
Keyword(s):  
Social Impact ◽  
Geographical Area ◽  
Infrastructure Development ◽  
Structured Interviews ◽  
Sustainable Business ◽  
Knowledge Resources ◽  
Business Events ◽  
And Performance ◽  
Event Based

The growth of the event sector is underpinned by the demand of organizing a business event.  Thus, it leads to an increase in economic and social impact. However, the problems from the growth of this sector potentially results from the use of several event materials, transportation and infrastructure development.  Organizing a green event is seen as one of the strategies to reduce the environmental impact.  Therefore, the aim of this paper is to explore the issues involved throughout the process of greening an event by applying Mair and Jago Model.  Semi-structured interviews were conducted with event managers from six Malaysia business event companies that encourage green practices during their event.  Findings suggest that impact, initiative, support and performance motivates event organizers in organizing a green event.  It has also been found that knowledge, resources and behaviour are the barriers faced by event organizers throughout the process of organizing a green event.  Based on the findings it appears that two important factors have emerged from the data collection and analysis that showed a deviation from the Mair and Jago Model, namely “impact” for the motivation element and “support” for the barrier element.  The main limitation of this study was the scope of the study; as it only focuses on business events.  However, as the main purpose of this study is to explore the issues of organizing a green event, it has been found that there are other issues need to be explored in other contexts and geographical area.  Apart from this, as this is a case study, it can only replicate according to the circumstances of this case study. However, this study can be generalized in terms of the theory that has emerged from it.  It is suggested that further research should explore more issues in other contexts and geographical areas. 

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