Modelling dynamic characteristics of the IGBT with thermal phenomena taken into account

2017 ◽  
Vol 34 (3) ◽  
pp. 160-164 ◽  
Author(s):  
Krzysztof Górecki ◽  
Paweł Górecki
Keyword(s):  
Design Methodology ◽  
Thermal Characteristics ◽  
Thermal Inertia ◽  
Bipolar Transistors ◽  
Insulated Gate Bipolar Transistors ◽  
Switching Circuit ◽  
Content Type ◽  
Different Types ◽  
Thermal Phenomena ◽  
Good Agreement

Purpose This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE. Design/methodology/approach The electrothermal model of this device (IGBT), which takes into account both electrical and thermal phenomena, is described. Particularly, the sub-threshold operation of this device is considered and electrical, and thermal inertia of this device is taken into account. Attention was focused on the influence of electrical and thermal inertia on waveforms of terminal voltages of the considered transistor operating in the switching circuit and on waveforms of the internal temperature of this device. Findings The correctness of the presented model is verified experimentally and a good agreement of the calculated and measured electrical and thermal characteristics of the considered device is obtained. Research limitations/implications The presented model can be used for different types of IGBT, but it is dedicated for SPICE software only. Originality/value The form of the worked out model is presented and the results of experimental verification of this model are shown.

Danfoss drives a hard bargain with suppliers

2006 ◽  
Vol 22 (9) ◽  
pp. 5-7
Keyword(s):  
Design Methodology ◽  
Bipolar Transistors ◽  
Supplier Evaluation ◽  
Collaborative Approach ◽  
Insulated Gate Bipolar Transistors ◽  
Content Type ◽  
Potential Benefits ◽  
Electrical Motors ◽  
The Relationship

PurposeExamines the relationship between Danfoss Drives, a Danish company that produces apparatus for regulating the frequencies of electrical motors, and its four suppliers of so‐called “insulated gate bipolar transistors” (IGBTs), which are a key component of these devices.Design/methodology/approachExamines the reactions of each of the four suppliers to the Danfoss “supplier evaluation” meetings, the main aim of which seemed to be to force down prices.FindingsDiscovers that only one of the four suppliers reacted positively to the Danfoss approach, and that varying degrees of resentment were present in the others.Originality/valueHighlights the potential benefits of a more collaborative approach when purchasing certain types of products.

Modelling mutual thermal coupling in LED modules

2015 ◽  
Vol 32 (3) ◽  
pp. 152-157 ◽  
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Thermal Characteristics ◽  
Thermal Inertia ◽  
Thermal Coupling ◽  
Cooling Systems ◽  
Content Type ◽  
Light Emitting ◽  
Common Base ◽  
The Common ◽  
Practical Implications ◽  
Good Agreement

Purpose – The purpose of this paper is to present an electrothermal model of the module containing power light emitting diodes (LEDs) situated on a common base. Design/methodology/approach – The electrothermal model of this device, which takes into account both self-heating and mutual thermal coupling between the diodes situated in this module, is described. Findings – The correctness of the presented model is verified experimentally, and a good agreement of the calculated and measured optical and thermal characteristics of the considered module is obtained. Research limitations/implications – The presented model can be used for different structures of the LED module, but electrical inertia in the diodes is omitted. Practical implications – The presented model was used to calculate electrical, thermal and optical waveforms of the module OSPR3XW1 containing three power LED situated on the common base. Originality/value – The presented model takes into account thermal inertia in the considered LED module and its cooling systems with mutual thermal coupling between all the diodes situated in the same module.

scholarly journals Accurate Circuit-Level Modelling of IGBTs with Thermal Phenomena Taken into Account

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2372
Author(s):  
Paweł Górecki ◽  
Krzysztof Górecki ◽  
Janusz Zarębski
Keyword(s):  
Integrated Circuit ◽  
Bipolar Transistors ◽  
Classical Literature ◽  
Insulated Gate Bipolar Transistors ◽  
Spice Simulation ◽  
Proposed Model ◽  
Wide Range ◽  
Thermal Phenomena ◽  
Parameter Values ◽  
Good Agreement

This paper proposes a new compact electrothermal model of the Insulated Gate Bipolar Transistors (IGBT) dedicated for SPICE (Simulation Program with Integrated Circuit Emphasis). This model makes it possible to compute the non-isothermal DC characteristics of the considered transistor and the waveforms of terminal voltages and currents of the investigated device and its internal temperature at transients. This model takes into account the nonlinearity of thermal phenomena in this device. The form of the formulated model is described and the problem of estimating its parameter values is discussed. The correctness of the proposed model was verified experimentally both at DC operation and at transients. The obtained results are compared to the results of computations performed with the use of the classical literature model. A very good agreement between the results of measurements and computations performed with the new model is obtained at different cooling conditions and in a wide range of changes of parameters characterising the electrical excitation of the tested device.

scholarly journals Advantages and potential challenges of data management in e-maintenance

2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo
Keyword(s):  
Data Management ◽  
Design Methodology ◽  
Management Practices ◽  
Future Research ◽  
Conceptual Approach ◽  
Content Type ◽  
Different Types ◽  
Maintenance Systems ◽  
Industry Leader ◽  
Practical Implications

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.

Evaluation of compression-recovery and thermal characteristics of multilayer bedding textiles

2020 ◽  
Vol 32 (5) ◽  
pp. 631-643
Author(s):  
Sedat Özer ◽  
Yaşar Erayman Yüksel ◽  
Yasemin Korkmaz
Keyword(s):  
Thermal Conductivity ◽  
Sleep Quality ◽  
Thermal Comfort ◽  
Sleep Duration ◽  
Human Body ◽  
Design Methodology ◽  
Thermal Characteristics ◽  
Air Permeability ◽  
Content Type ◽  
Thermal Comfort Properties

PurposeDesign of bedding textiles that contact the human body affects the sleep quality. Bedding textiles contribute to comfort sense during the sleep duration, in addition to ambient and bed microclimate. The purpose of this study is to evaluate the effects of different layer properties on the compression recovery and thermal characteristics of multilayer bedding textiles.Design/methodology/approachIn this study, woven and knitted multilayer bedding textiles were manufactured from fabric, fiber, sponge and interlining, respectively. Different sponge thickness, fiber and interlining weight were used in the layers of samples. Later, the pilling resistance, compression and recovery, air permeability and thermal conductivity of multilayer bedding textiles were investigated.FindingsThe results indicated that samples with the higher layer weight and thickness provide better compression recovery and lower air permeability properties. It was also found that knitted surfaces show the higher air permeability than the woven surfaces depending on the fabric porosity. Layer properties have insignificant effect on the thermal conductivity values.Originality/valueWhile researchers mostly focus on thermal comfort properties of garments, there are limited studies about comfort properties of bedding textiles in the literature. Furthermore, compression recovery properties of bedding textiles have also a great importance in terms of comfort. Originality of this study is that these properties were analyzed together.

Online brand communities as heterogeneous gatherings: a netnographic exploration of Apple users

2017 ◽  
Vol 26 (4) ◽  
pp. 375-385 ◽  
Author(s):  
Tuğba Özbölük ◽  
Yunus Dursun
Keyword(s):  
Design Methodology ◽  
Participant Observation ◽  
Opinion Leader ◽  
Brand Community ◽  
Community Members ◽  
Content Type ◽  
Brand Communities ◽  
Online Brand Communities ◽  
Different Types ◽  
Online Brand Community

Purpose This paper aims to investigate the different types of members based on their roles within an online brand community dedicated to Apple. Design/methodology/approach Design/methodology/approach Data are drawn from an 18-month netnographic study, including participant and non-participant observation. Findings Findings reveal that members of the online brand community share a common goal but they are heterogeneous in many respects. In this research, five different types of brand community members are identified: learner, pragmatist, activist, opinion leader and evangelist. These findings emphasize the heterogeneity of the brand community or the differences of members and subgroups they form in the community. Practical implications This paper offers some insights for brand managers. There are different sub-tribes in online brand communities and these sub-tribes develop their own meanings of the brand. This means that online brand communities do not form one single homogenous target group and can be segmented into subgroups. Findings also offer a deeper understanding of negative characteristics of online brand community members. The role “activist” found in this study may be crucial for marketers, as activists can represent the negative side of online brand communities. Originality/value The literature on brand communities has focused predominantly on the homogeneity of these communities. This paper extends the literature by demonstrating the heterogeneity in an online brand community. The paper contributes to the brand community literature by substantiating that online brand community members can be segmented into subgroups based on their roles within the community. In addition, the paper extends the existing literature on brand communities that has overlooked the destructive consumer roles.

Performance assessment of the complex repairable system with n-identical units under (k-out-of-n: G) scheme and copula linguistic repair approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
V. V. Singh ◽  
Abubakkar Idris Mohhammad ◽  
Kabiru Hamisu Ibrahim ◽  
Ibrahim Yusuf
Keyword(s):  
Complex System ◽  
Design Methodology ◽  
New Method ◽  
Social Implications ◽  
Repairable System ◽  
Variable Technique ◽  
Content Type ◽  
Different Types ◽  
Theoretical Assessment ◽  
Practical Implications

PurposeThis paper analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The computed results are more supportable for repairable system performability analysis.Design/methodology/approachIn this paper, the authors have analyzed a complex system consisting n-identical units under a k-out-of-n: G; configuration via a new method which has not been studied by previous researchers. The supplementary variable technique has employed for analyzing the performance of the system.FindingsReliability measures have been computed for different types of configuration. It generalized the results for purely series and purely parallel configurations.Research limitations/implicationsThis research may be beneficial for industrial system performances whereas a k-out-of-n-type configuration exists.Practical implicationsNot sure as it is a theoretical assessment.Social implicationsThis research may not have social implications.Originality/valueThis work is the sole work of authors that have not been communicated to any other journal before.

Career satisfaction antecedents of professional accounting returnees in international workplaces: an employee experience perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nga Thi Thuy Ho ◽  
Hung Trong Hoang ◽  
Pi-Shen Seet ◽  
Janice Jones ◽  
Nhat Tan Pham
Keyword(s):  
Design Methodology ◽  
Career Satisfaction ◽  
Home Country ◽  
Well Being ◽  
Cross Cultural ◽  
Cultural Work ◽  
Content Type ◽  
Different Types ◽  
Employee Experience ◽  
Practical Implications

PurposeThe purpose of this study is to examine the determinants of career satisfaction of professional accounting returnees who have studied and/or worked abroad and then returned to work in different types of international workplaces in their home country.Design/methodology/approachA survey of professional accounting returnees in Vietnam was undertaken and multiple regression analysis was applied to test the proposed relationships.FindingsThis study finds that career satisfaction is affected by career fit, career sacrifice, types of international workplaces (domestically headquartered firms versus globally headquartered firms) and cross-cultural work readjustment. Further, cross-cultural work readjustment partially mediates the effect of career fit and career sacrifice on career satisfaction.Practical implicationsThe research provides the basis for designing career-related employee experiences to support career satisfaction of professional accounting returnees.Originality/valueThis study integrates dimensions of career embeddedness with cross-cultural work readjustment and employee experiences, which are normally studied separately, in different types of international workplaces. It contributes to the limited research on contributors to well-being in the form of career satisfaction among professional returnees in an emerging economy.

An investigation into the Community of Inquiry model in the Malaysian ESL learners’ context

2017 ◽  
Vol 14 (3) ◽  
pp. 246-263
Author(s):  
Nagaletchimee Annamalai
Keyword(s):  
Creative Thinking ◽  
Design Methodology ◽  
Community Of Inquiry ◽  
Cognitive Presence ◽  
Online Environment ◽  
Content Type ◽  
Different Types ◽  
Emerging Themes ◽  
Esl Learners ◽  
Writing Task

Purpose This study aims to explore how the Community of Inquiry (CoI) model (2000) is used to categorize students’ and teachers’ interactions in an asynchronous discussion and how these interactions are able to help students add quality to their narrative writing. Design/methodology/approach The interactions were categorized based on teaching, social and cognitive presences suggested by the CoI model. Data collection included online archives and students’ narrative essays. Content analysis was performed based on the presences suggested by the CoI model. Scores for the narrative essays were based on Tribble’s (1996) assessment scale. Findings The findings indicated that the interactions were significantly related to the cognitive, teaching and social presences. However, the cognitive presence indicated a distinctive pattern. As this was a qualitative study, there were emerging themes. The study found that critical thinking was minimal, as the writing task was related to creative thinking. Research limitations/implications It is suggested that writing in the online environment should also consider different types of writing. Originality/value The emerging themes can be used to enhance and complement the CoI model when used in the Malaysian setting.

scholarly journals Putting resilient sustainability into strategy decisions – case studies

2018 ◽  
Vol 56 (7) ◽  
pp. 1598-1612 ◽  
Author(s):  
Julie Winnard ◽  
Jacquetta Lee ◽  
David Skipp
Keyword(s):  
Case Studies ◽  
Real World ◽  
Design Methodology ◽  
Strategic Decision ◽  
New Approach ◽  
Content Type ◽  
Industrial Companies ◽  
Different Types ◽  
Strategic Decision Support ◽  
Practical Implications

Purpose The purpose of this paper is to report the results of testing a new approach to strategic sustainability and resilience – Sustainable Resilient Strategic Decision-Support (SuReSDS™). Design/methodology/approach The approach was developed and tested using action-research case studies at industrial companies. It successfully allowed the participants to capture different types of value affected by their choices, optimise each strategy’s resilience against different future scenarios and compare the results to find a “best” option. Findings SuReSDS™ enabled a novel integration of environmental and social sustainability into strategy by considering significant risks or opportunities for an enhanced group of stakeholders. It assisted users to identify and manage risks from different kinds of sustainability-related uncertainty by applying resilience techniques. Users incorporated insights into real-world strategies. Research limitations/implications Since the case studies and test organisations are limited in number, generalisation from the results is difficult and requires further research. Practical implications The approach enables companies to utilise in-house and external experts more effectively to develop sustainable and resilient strategies. Originality/value The research described develops theories linking sustainability and resilience for organisations, particularly for strategy, to provide a new consistent, rigorous and flexible approach for applying these theories. The approach has been tested successfully and benefited real-world strategy decisions.

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