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Article

Martin Marco Nell, Benedikt Groschup and Kay Hameyer

This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure…

Abstract

Purpose

This paper aims to use a scaling approach to scale the solutions of a beforehand-simulated finite element (FE) solution of an induction machine (IM). The scaling procedure is coupled to an analytic three-node-lumped parameter thermal network (LPTN) model enabling the possibility to adjust the machine losses in the simulation to the actual calculated temperature.

Design/methodology/approach

The proposed scaling procedure of IMs allows the possibility to scale the solutions, particularly the losses, of a beforehand-performed FE simulation owing to temperature changes and therefore enables the possibility of a very general multiphysics approach by coupling the FE simulation results of the IM to a thermal model in a very fast and efficient way. The thermal capacities and resistances of the three-node thermal network model are parameterized by analytical formulations and an optimization procedure. For the parameterization of the model, temperature measurements of the IM operated in the 30-min short-time mode are used.

Findings

This approach allows an efficient calculation of the machine temperature under consideration of temperature-dependent losses. Using the proposed scaling procedure, the time to simulate the thermal behavior of an IM in a continuous operation mode is less than 5 s. The scaling procedure of IMs enables a rapid calculation of the thermal behavior using FE simulation data.

Originality/value

The approach uses a scaling procedure for the FE solutions of IMs, which results in the possibility to weakly couple a finite element method model and a LPTN model in a very efficient way.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Martin Marco Nell, Georg von Pfingsten and Kay Hameyer

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…

Abstract

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.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Georg von Pfingsten, Martin Marco Nell and Kay Hameyer

Induction machines for traction applications are operated at working points of high ferromagnetic saturation. Depending on the working point, a broad spectrum of harmonic…

Abstract

Purpose

Induction machines for traction applications are operated at working points of high ferromagnetic saturation. Depending on the working point, a broad spectrum of harmonic frequencies appears in the magnetic flux density of induction machines. Detailed loss analysis therefore requires local and temporal highly resolved nonlinear field computation. This loss analysis can be performed in the post processing of nonlinear transient finite element simulations of the magnetic circuit. However, it takes a large number of transient simulation time steps to build up the rotor flux of the machine.

Design/methodology/approach

In this paper, hybrid simulation approaches that couple static FEA, transient FEA and analytic formulations to significantly decrease the number of simulation time steps to calculate the magnetic field in steady state are discussed, analyzed and compared.

Findings

The proposed hybrid simulation approaches drastically decrease the simulation time by shortening the transient build-up of the rotor flux. Depending on the maximum error of the rotor flux linkage amplitude compared to the steady state value, a reduction of simulation time steps in the range of 55.5 to 98 per cent is found.

Originality/value

The presented hybrid simulation approaches allow efficient performing of the transient FE magnetic field simulations of induction machines operated as traction drives.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Book part

Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of…

Abstract

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.

Details

Advances in Environmental Accounting & Management: Social and Environmental Accounting in Brazil
Type: Book
ISBN: 978-1-78635-376-4

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Book part

Alexander J. Martín

Archaeological evidence from the prehistoric Spondylus industry of coastal Ecuador is analyzed here to clarify how craft production was structured and the role that it…

Abstract

Archaeological evidence from the prehistoric Spondylus industry of coastal Ecuador is analyzed here to clarify how craft production was structured and the role that it played in the rise of social complexity. Many models of social development propose that elite cooption of specialized craft production can be a useful avenue through which aspiring elites can gain differential status. Contrary to the expectations of these models, data from coastal Ecuador indicates that craft production of sumptuary goods was an activity primarily carried out by household units for the benefit of the domestic economy. Increased trafficking with northern Peruvian states at ca. 750 seems to have promoted local social stratification by attracting large numbers of households to the restricted locales where they could exploit these resources, which in turn prompted a strengthening of the kinds of political conditions that facilitate orderly interaction and minimize internal social conflict.

Details

Economic Action in Theory and Practice: Anthropological Investigations
Type: Book
ISBN: 978-0-85724-118-4

Abstract

Details

The Overtourism Debate
Type: Book
ISBN: 978-1-83867-487-8

Abstract

Details

Journal of Small Business and Enterprise Development, vol. 15 no. 3
Type: Research Article
ISSN: 1462-6004

Keywords

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Article

Louise Curran and Soledad Zignago

The fact that many international companies remain strongly orientated towards their home region has been highlighted in the work of several international business…

Abstract

Purpose

The fact that many international companies remain strongly orientated towards their home region has been highlighted in the work of several international business scholars. This work has given rise to the concept of “the liability of inter‐regional foreignness”. This paper aims to argue that the data that have so far been exploited in this debate are too aggregated and that more attention needs to be paid to differences between different types of companies if we are to better understand the reasons for this liability of inter‐regional foreignness and how companies can overcome it.

Design/methodology/approach

This paper uses trade data to explore levels of global and regional orientation in international exchanges of goods. It disaggregates the trade data by type of product (final goods or inputs to production), level of technology (high, medium and low tech) and direction of flow (imports and exports).

Findings

The paper finds striking differences between regions, types of products and trade direction. The trade data do not show an overwhelming home region bias in exchanges, but neither are these exchanges overwhelmingly global. Companies in different regions and different sectors seem to experience the liability of inter‐regional foreignness differently. In particular there is some evidence that high‐tech companies may be less subject to such difficulties. These findings imply that more attention needs to be paid to sectoral differences when analysing international business.

Research limitations/implications

The trade data also suffer from some aggregation bias, as highlighted in the paper. In addition the inability to differentiate between inter‐ and intra‐firm trade limits the usefulness for theory building. However the results do provide some pointers for further research and imply that greater attention should be paid to the type of company and its position in the supply chain when considering the impact of the liability of inter‐regional foreignness.

Originality/value

The debate so far has been based on either Fortune 500 data or foreign direct investment data. Both of these datasets mix companies with very different market structures and operating practices. The originality of this work is to explore macro data extensively and look at exchanges differentiating by type of good. The results have implications for work on aggregated datasets. Simply differentiating by technology alone may lead to interesting variations in findings from firm‐level studies.

Details

Critical perspectives on international business, vol. 8 no. 3
Type: Research Article
ISSN: 1742-2043

Keywords

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Abstract

Details

Accounting for the Environment: More Talk and Little Progress
Type: Book
ISBN: 978-1-78190-303-2

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Abstract

Details

The Overtourism Debate
Type: Book
ISBN: 978-1-83867-487-8

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