Design and performance analysis of novel multiphase induction motor with die-cast copper rotors using FEA for electric propulsion vehicles applications

Circuit World ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 271-280
Author(s):  
Sathishkumar Kaliyavarathan ◽  
Sivakumaran T.S.

Purpose The purpose of this paper is to study the development of novel multiphase induction motor (MPIM) with copper die cast rotor in the drive system of electric propulsion vehicles (EPV). It is estimated that the manufacturers are concerned about high torque,Efficiency, motor life, energy conservation and high thermal tolerance. To ensure maximum torque and efficiency with multiphase winding and copper die cast technology to increasing high thermal tolerance, life, energy conversations. On other hand, it is very important of EPV application. Design/methodology/approach The focus of the investigation is threefold: the modified method carried out on MPIM both stator and rotor can overcome the current scenario problem facing by electric vehicles manufacture and developed perfect suitable electric motor for EPV applications. The design and simulation carried out finite element method (FEM) that was more accurate calculations. Finally developed prototype model of MPIM with copper die cast are discussed with conventional three phase Die casting Induction motor. Findings The paper confirmed the multiphase copper die-cast rotor induction motor (MDCrIM) is providing better performance than conventional motor. Proposed motor can bring additional advantage like heat tolerances, long life and energy conversations. Originality/value The experiments confirmed the MDCIM suitable for EPV Applications. The modified MDCIM of both stator and rotor are giving better result and good performance compared to conventional method.

Author(s):  
Ying Xie ◽  
Ze Wang ◽  
Xueting Shan ◽  
Yangyang Li

Purpose Thermal stress of the rotor in a squirrel cage induction motor is generated due to the temperature rise, and the structure of the rotor will be destroyed if the stress acted on the rotor exceeds its limits, so the thermal stress is also one of the main causes led to broken bar fault. The purpose of this paper is to report the thermal stress coupled analysis for the induction motor with healthy and faulty rotor, and to find the variation tendency of the temperature and thermal stress due to broken bars, and the part most likely to break in the rotor as a result of the thermal stress load are identified. Design/methodology/approach The steady temperature and thermal stress of the rotor in the case of the healthy and faulty conditions are calculated by finite element method, and the 3D model of the motor used in the experiments is established and the experimental results are presented for both healthy and faulty machines. Findings The influence of the broken bars fault on the motor thermal profile and thermal stress can be found, and it explains why the breaking point always appears in the joint of the bars and end rings. Originality/value The paper presents the 3D thermal stress coupled model and performance characteristics of induction motor with broken bars. The reasonable constraint is established according to the contact of components each other, and more reasonable fracture location is selected. The results obtained by the simulation model are in a good agreement with practical situation, because the effect of skewed rotor were taken into consideration in the process of simulation.


Author(s):  
Imen Nouira El Badsi ◽  
Bassem El Badsi ◽  
Ahmed Masmoudi

PurposeThis paper aims to investigate the performance of two novel direct torque control (DTC) schemes dedicated to three-switch three-phase inverter (B3-VSI), also called delta inverter, fed induction motor (IM) drives.Design/methodology/approachThe principle of operation of the B3-VSI-fed IM drive is recalled in a first step. Then, the basis of both proposed DTC strategies is presented. The first DTC scheme considers a subdivision of the stationary plane into three sectors and the application of the intrinsic as well as virtual voltage vectors to achieve the control combinations. While, the second DTC scheme considers a subdivision of the stationary plane into six sectors and a limitation of the voltage vectors incorporated in the look-up table to the three intrinsic ones.FindingsSimulation and experimental results have revealed that, under steady-state operation and transient conditions, the harmonic content of the IM stator phase currents is lower in the case of the DTC2 strategy, resulting in a lower ripple of electromagnetic torque. Furthermore, it has led to a quasi-circular shape of the locus described by the stator flux vector in the stationary plane.Research limitations/implicationsThis work should be extended to the synthesis and performance analysis of a new DTC strategy for B3-VSI-fed IM drive, which emulates the operation of the conventional six-switch three-phase inverter-fed IM drive.Originality/valueThe limitation associated with the reduced number of the intrinsic voltage vectors generated by the B3-VSI has been eradicated, thanks to the suitable synthesis of the look-up table incorporated in the DTC scheme.


2019 ◽  
Vol 34 (6) ◽  
pp. 429-442 ◽  
Author(s):  
Manuel London

Purpose Drawing on existing theory, a model is developed to illustrate how the interaction between leaders and followers similarity in narcissism and goal congruence may influence subgroup formation in teams, and how this interaction influences team identification and team performance. Design/methodology/approach The proposed model draws on dominance complementary, similarity attraction, faultline formation and trait activation theories. Findings Leader–follower similarity in narcissism and goal congruence may stimulate subgroup formation, possibly resulting in conformers, conspirators, outsiders and victims, especially when performance pressure on a team is high. Followers who are low in narcissism and share goals with a leader who is narcissistic are likely to become conformers. Followers who are high in narcissism and share goals with a narcissistic leader are likely to become confederates. Followers who do not share goals with a narcissistic leader will be treated by the leader and other members as outsiders if they are high in narcissism, and victimized if they are low in narcissism. In addition, the emergence of these subgroups leads to reduced team identification and lower team performance. Practical implications Higher level managers, coaches and human resource professions can assess and, if necessary, counteract low team identification and performance resulting from the narcissistic personality characteristics of leaders and followers. Originality/value The model addresses how and under what conditions narcissistic leaders and followers may influence subgroup formation and team outcomes.


2020 ◽  
Vol 20 (6) ◽  
pp. 1073-1090 ◽  
Author(s):  
Ejaz Aslam ◽  
Razali Haron

Purpose Corporate governance plays a significant role to overcome agency issues and develop the culture of transparency and openness. In this context, this paper aims to examine how corporate governance mechanisms affect the performance of Islamic banks (IBs). Design/methodology/approach Stepwise, two-step system generalize method of moment estimation technique is used in the analysis in which control variables are added into the model sequentially. This study used data on 129 IBs from 29 Islamic countries (Middle East, South Asia and Southeast Asia) during the period of 2008 to 2017. Findings The findings suggest that the audit committee (AUDC) and Shariah board (SB) have positive impact on the performance of IBs (return on assets and return on equity). However, board size and risk management committee have negative and significant effect on the performance of IBs. CEO duality and non-executive directors have mixed relationship with the performance of IBs. These results support the argument that IBs need to improve their financial performance through appropriate governance mechanism. Research limitations/implications The findings of the study added a new dimension to the governance research that could be a valuable source of knowledge for policymakers and regulators to improve the existing governance mechanism for better performance of IBs. Originality/value The study fills the gap in the literature by addressing the issue of corporate governance on performance of IBs across countries. Agency theory is discussed to explain the relationship between corporate governance mechanism and performance.


2019 ◽  
Vol 13 (1) ◽  
pp. 29-48 ◽  
Author(s):  
Abdullah Al Mamun ◽  
Syed Ali Fazal ◽  
Rajennd Muniady

Purpose This study aims to examine the effect of entrepreneurial skills, market orientation, sales orientations and networking on entrepreneurial competency and performance of micro-enterprises in Kelantan, Malaysia. Design/methodology/approach Adopting a cross-sectional design, this paper collected data through structured interviews from 403 micro-entrepreneurs from “Majlis Amanah Rakyat,” Kelantan and “Majlis Agama Islam dan Adat Istiadat,” Kelantan. Findings The findings reveal that entrepreneurial skills, market orientation and networking have a positive effect on entrepreneurial competency. Then, entrepreneurial competency, entrepreneurial skills and networking have a positive effect on enterprise performance. The findings show a significant mediation effect of entrepreneurial competency on the relationships between entrepreneurial skills, market orientation and networking and enterprise performance. Originality/value Addressing the understudied “human factor” in entrepreneurship, this paper extends the resource-based view and enriches the existing entrepreneurship literature in Malaysia. It provides useful insights into the improvement of micro-enterprise performance, which is crucial for promoting entrepreneurial activities and for enhancing socio-economic conditions among low-income households in Malaysia. Thus, the government and developmental organizations should focus on the development of entrepreneurial skills, market-oriented approach, networking traits and entrepreneurial competencies and subsequently encourage poor households to perform entrepreneurial activities.


2014 ◽  
Vol 81 (5) ◽  
pp. 1661-1667 ◽  
Author(s):  
Santosh Kumar Tiwari ◽  
Katia Sutyak Noll ◽  
Veronica L. Cavera ◽  
Michael L. Chikindas

ABSTRACTTwo hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64- and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8- and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wild-type (WT) bacteriocins on the transmembrane electrical potential (ΔΨ) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ΔΨ, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such asMicrococcus luteus,Salmonella entericaserovar Enteritidis 20E1090, andEscherichia coliO157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics.


2014 ◽  
Vol 52 (5) ◽  
pp. 897-915 ◽  
Author(s):  
Yan Chen ◽  
Yiwei Jiang ◽  
Chengqi Wang ◽  
Wen Chung Hsu

Purpose – The purpose of this paper is to examine how firm resources and diversification strategy explain the performance consequences of internationalization of emerging market enterprises. Design/methodology/approach – The paper conducts a regression analysis by using a novel panel data set comprising of 685 listed Chinese firms over the period of 2008-2011. Findings – The results show that the relationship between internationalization and performance is inverse U-shaped. Further, marketing resources play a greater role in enhancing the performance effects of internationalization than technological resources do. Related product diversification enhances the performance effects, while unrelated product diversification does the contrary. Research limitations/implications – The study focusses on listed firms in one country, and as a result, the findings cannot be generalized to non-listed firms and firms in other countries. Practical implications – This paper offers guidelines for international managers to improve performance of internationalization by developing a particular type of resources and diversification strategy. Originality/value – This paper extends the literature on the functional form of the internationalization-performance relationship, and further suggests that the analysis of the performance consequences of internationalization should go beyond the nexus between internationalization and performance, and focusses on firm-specific resources and strategies that may facilitate or constrain the performance effects of internationalization.


2018 ◽  
Vol 8 (4) ◽  
pp. 376-394 ◽  
Author(s):  
Sonali Bhattacharya ◽  
Netra Neelam

Purpose The purpose of this paper is to examine how internship value is manifested in the context of a business school. The authors have examined the internship experience in terms of experiential learning and employability. Specifically, the authors investigate the factors that determine internship at four phases: design, conduct, evaluation and feedback. Design/methodology/approach The authors have applied a mixed method approach. In all, 110 students of a busines school were first surveyed on their expectation, motivation and level of preparation through a self-administered questionnaire before internship. Based on the survey result, eight of these students were interviewed in details about internship expectations from industry, the selection process for internship, communications or exchanges between intern and companies prior to internship and perceived industry expectation from interns. At the next phase, authors used a qualitative research approach by conducting semi-structured, in-depth interviews with 14 interns and their mentors after internship period. They were interviewed on design, conduct, evaluation and feedback process of the internship. Interviews tried capture what kind of leader-member exchange led to satisfactory internship experience and outcome from view of both inter and mentor. Findings The authors find that at various stages of internship program quality of mentor – intern exchanges (as defined by leadership exchange theory), and task characteristics as indicated by autonomy, task variety, task significance and performance feedback determine intern’s performance. An intern’s performance is antecedent to an intern’s and a mentor’s satisfaction and overall internship value. The authors also found that intrinsic capability of intern such as critical thinking ability and learning orientation result in enhanced value of internship experience. The proposed models, postulate that at designing stage, lower the level of communication from employers, higher the feeling of ambiguity and lower the perceived internship value in terms of experiential learning and perceived employability. Feeling of ambiguity is moderated by existence of prior work experience of interns. At conduction stage, mentor-intern exchange is directly related to flexibility in structure of the program and inversely related to dependency on peer learning. Mentor-intern exchange also related to mentor and intern’s learning value. However, the learning value is moderated by learning orientation of the intern. Originality/value The authors have tried the summer internship experience from the perspective of interns and mentors. This is the uniqueness of the research.


2017 ◽  
Vol 16 (4) ◽  
pp. 155-160
Author(s):  
Ian Johnston

Purpose This paper aims to show that everything a business does is fundamentally reliant on its culture. Culture determines how successful a strategy is and whether that strategy can be executed. If the culture in a business is out of alignment, it is imperative to change it. This paper examines how HR professionals can take ownership of this cultural space and help to create a growth mindset throughout the organisation. Design/methodology/approach The paper is based on experience gained through working with several large organisations to transform their people culture and performance by embracing a growth mindset and to help their HR leadership become the early champions of change, thus ensuring the process was successfully delivered. The paper includes case studies of two organisations where successful cultural shaping delivered improved results. Findings Companies with a growth mindset will outperform those with a fixed mindset. Changing mindsets is not overly complex, but it requires flawless implementation with the HR leaders at the forefront. Originality/value As Lou Gerstner, who turned around the computing giant IBM, said “I finally realised that culture is not part of the game, it is the game”. By understanding how individual mindsets impact culture, HR professionals can own and drive their organisation’s culture-shaping efforts.


2015 ◽  
Vol 42 (12) ◽  
pp. 1071-1089
Author(s):  
Alan Chan ◽  
Bruce G. Fawcett ◽  
Shu-Kam Lee

Purpose – Church giving and attendance are two important indicators of church health and performance. In the literature, they are usually understood to be simultaneously determined. The purpose of this paper is to estimate if there a sustainable church congregation size using Wintrobe’s (1998) dictatorship model. The authors want to examine the impact of youth and adult ministry as well. Design/methodology/approach – Using the data collected from among Canadian Baptist churches in Eastern Canada, this study investigates the factors affecting the level of the two indicators by the panel-instrumental variable technique. Applying Wintrobe’s (1998) political economy model on dictatorship, the equilibrium level of worship attendance and giving is predicted. Findings – Through various simulation exercises, the actual church congregation sizes is approximately 50 percent of the predicted value, implying inefficiency and misallocation of church resources. The paper concludes with insights on effective ways church leaders can allocate scarce resources to promote growth within churches. Originality/value – The authors are the only researchers getting the permission from the Atlantic Canada Baptist Convention to use their mega data set on church giving and congregation sizes as per the authors’ knowledge. The authors are also applying a theoretical model on dictatorship to religious/not for profits organizations.


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