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Article
Publication date: 1 January 2012

Yang Tang, Johannes J.H. Paulides, Evgeny Kazmin and Elena A. Lomonova

This paper aims to find the optimal winding topology for a 14‐pole permanent magnet synchronous motor (PMSM) to be used as an in‐wheel motor in automotive applications.

Abstract

Purpose

This paper aims to find the optimal winding topology for a 14‐pole permanent magnet synchronous motor (PMSM) to be used as an in‐wheel motor in automotive applications.

Design/methodology/approach

Comparison is first performed among lap windings with different combinations of slot numbers and pole numbers. A general method for calculating the winding factors using only these numbers is proposed, thus the preferable slot numbers resulting in relatively large winding factors for this 14‐pole PMSM are found. With these slot numbers, the Joule losses of armature windings are further investigated, where the impacts of different end‐winding lengths are considered. By this means, the optimal slot number that causes the least Joule loss is obtained. On the other hand, as a competitor to lap windings, toroidal windings are also discussed. The thermal performances of these two types of windings are compared by performing a finite element analysis (FEA) on their 2‐D thermal models.

Findings

For the 14‐pole in‐wheel PMSM discussed in this paper, the preferable slot numbers leading to relatively large winding factors are 12, 15 and 18. However, with the specified geometry constraints, the optimal choice of slot number is 15, which results in the least Joule loss and thus the highest efficiency. On the other hand, by implementing the toroidal winding topology, the armature windings of this machine can be effectively cooled and thus allow a larger electrical loading than the lap windings do.

Research limitations/implications

This work can be continued with investigating the impacts of different combinations of slot number and pole number on harmonics and cogging torques.

Originality/value

This paper proposes a general method for calculating the winding factor of PMSMs using only the phase number, the slot number, and the pole number. With this method, the calculation procedure can be easily programmed and repeated.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 31 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 September 2018

Lufeng Zhang and Kai Wang

The purpose of this paper is to investigate the electromagnetic performances of the permanent magnet linear synchronous machines (PMLSM) with sine and third harmonic (SIN + 3rd…

Abstract

Purpose

The purpose of this paper is to investigate the electromagnetic performances of the permanent magnet linear synchronous machines (PMLSM) with sine and third harmonic (SIN + 3rd) shaping mover in comparison with the PMLSM with sine (SIN) shaping mover and conventional shaping mover.

Design/methodology/approach

The optimal amplitude of the injected third harmonic to re-shape the SIN + 3rd shaping permanent magnet (PM) for maximizing the thrust force is analytically derived and confirmed by finite element method (FEM). Furthermore, the PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio are optimized. It is found that the optimal amplitude of the injected third harmonic is one-sixth of the fundamental one, the optimal PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio are 0, 0.85 and 0.5 mm, respectively. In addition, the electromagnetic performances are analyzed and quantitatively compared for the PMLSM with SIN + 3rd shaping mover, SIN shaping mover and conventional shaping mover.

Findings

The average thrust force and efficiency of the PMLSM with SIN + 3rd shaping mover are improved significantly, while the thrust ripple is not increased, comparing to those of the PMLSM with SIN shaping mover. Meanwhile, the thrust ripple is lower than that of the conventional shaping mover.

Research limitations/implications

The purely sinusoidal currents are applied in this analysis and the influences of harmonics in the current on electromagnetic performances are not considered.

Originality/value

This paper presents a PMLSM with SIN + 3rd shaping mover to improve the thrust force and efficiency without increasing the thrust ripple, considering the effects of the amplitude of the injected third harmonic to re-shape the SIN + 3rd shaping PM, the PM edge thickness, the pole arc to pole pitch ratio and the tooth to slot ratio.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 January 2021

Amin Farzin, Mehrangiz Ghazi, Amir Farhang Sotoodeh and Mohammad Nikian

The purpose of this study is to provide a method for designing the shell and tube heat exchangers and examine the total annual cost of heat exchanger networks from the economic…

Abstract

Purpose

The purpose of this study is to provide a method for designing the shell and tube heat exchangers and examine the total annual cost of heat exchanger networks from the economic view based on the careful design of equipment.

Design/methodology/approach

Accurate evaluation of heat exchanger networks performance depends on detailed models of heat exchangers design. The simulations variables include nine design variables such as flow direction determination of each of the two fluids, number of tubes, number of tube passes, length of tubes, the arrangement of tubes, size and percentage of baffle cut, tube diameter and tube pitch. The optimal designing of the heat exchangers is based on geometrical and hydraulic modeling and using a hybrid genetic particle swarm optimization algorithm (PSO-GA) technique. In this paper, optimization and minimization of the total annual cost of heat exchanger networks are considered as the objective function.

Findings

In this study, a fast and reliable method is used to simulate, optimize design parameters and evaluate heat transfer enhancement. PSO-GA algorithms have been used to minimize the total annual cost, which includes investment costs of heat exchangers and pumps, operating costs (pumping) and energy costs for utilities. Three case studies of four, six and nine streams are selected to demonstrate the accuracy of the method. Reductions of 0.55%, 23.5% and 14.78% are obtained in total annual cost for the selected streams, respectively.

Originality/value

In the present study, a reliable method is used to simulate and optimize design parameters and the economic optimization of the heat exchanger networks. Taking into account the importance of shell and tube heat exchangers in industrial applications and the complexity in their geometry, the PSO-GA methodology is adopted to obtain an optimal geometric configuration. The total annual cost is chosen as the objective function. Applying this technique to case studies demonstrates its ability to accurately design heat exchangers to optimize the objective function of the heat exchanger networks by giving the detail of design.

Details

Journal of Engineering, Design and Technology , vol. 19 no. 4
Type: Research Article
ISSN: 1726-0531

Keywords

Article
Publication date: 1 January 2013

M.F.J. Kremers, J.J.H. Paulides, T.E. Motoasca and E.A. Lomonova

The purpose of this paper is to discuss the performance of a proposed machine design for an in‐wheel motor with the required torque‐speed characteristic.

Abstract

Purpose

The purpose of this paper is to discuss the performance of a proposed machine design for an in‐wheel motor with the required torque‐speed characteristic.

Design/methodology/approach

Calculation of the winding factor of the machine with the star of slots theory is performed first. The field weakening capability of the machine is investigated and the operating speed range is determined. The tooth contour modeling method for calculating the performance of the machine with a limited number of elements is introduced. The method is used to construct two models of different complexity and the results obtained with the models are compared with the results obtained by finite element models.

Findings

The 14 pole 12 slot in‐wheel PMSM discussed in this paper is able to meet the stringent performance requirements. The results obtained with the tooth contour models show good agreement with the results obtained with finite element models despite the limited number of elements. Increasing the number of elements in the model allows for modeling of armature reaction and increases the accuracy of the model.

Research limitations/implications

This work can be continued with investigating the possibilities to model the armature reaction more accurately.

Originality/value

This paper proposes a modeling method which accurately describes the performance of a PMSM with limited number of elements. With this method, the calculation procedure can be easily used for optimization of the machine design.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Book part
Publication date: 30 October 2023

Robin Gustafsson, Kristian J. Sund and Robert J. Galavan

In this chapter, we reflect on cognitive aids and their role in strategy work. Strategy research and practice abound with frameworks, models, tools, and processes meant to…

Abstract

In this chapter, we reflect on cognitive aids and their role in strategy work. Strategy research and practice abound with frameworks, models, tools, and processes meant to describe and guide the strategy work of managers. These are all examples of cognitive aids. These aids guide and support managerial cognition, the way managers make sense of the world. What we collectively call the cognitive aids of strategy have a profound impact on the way managers learn about, conceptualize, share, and enact strategy work and strategies in their organizations. Despite the importance of their cognitive role, many cognitive aids in strategy are presented without reference to the underlying cognitive theory that explains why and how the aid might be useful. Tools are presented as useful for management thinking, but without any substantive reflection or exploration of the cognitive reasons. In this chapter, we provide a definition of cognitive aids in strategy and begin exploring the landscape of cognitive theories that can explain why something might be a cognitive aid. We then briefly outline the contributions to the edited volume “Cognitive Aids in Strategy,” and end with an invitation to expand your exploration beyond.

Details

Cognitive Aids in Strategy
Type: Book
ISBN: 978-1-83797-316-3

Keywords

Article
Publication date: 17 November 2021

Muharrem Selim Can and Hamdi Ercan

This study aims to develop a quadrotor with a robust control system against weight variations. A Proportional-Integral-Derivative (PID) controller based on Particle Swarm…

Abstract

Purpose

This study aims to develop a quadrotor with a robust control system against weight variations. A Proportional-Integral-Derivative (PID) controller based on Particle Swarm Optimization and Differential Evaluation to tune the parameters of PID has been implemented with real-time simulations of the quadrotor.

Design/methodology/approach

The optimization algorithms are combined with the PID control mechanism of the quadrotor to increase the performance of the trajectory tracking for a quadrotor. The dynamical model of the quadrotor is derived by using Newton-Euler equations.

Findings

In this study, the most efficient control parameters of the quadrotor are selected using evolutionary optimization algorithms in real-time simulations. The control parameters of PID directly affect the controller’s performance that position error and stability improved by tuning the parameters. Therefore, the optimization algorithms can be used to improve the trajectory tracking performance of the quadrotor.

Practical implications

The online optimization result showed that evolutionary algorithms improve the performance of the trajectory tracking of the quadrotor.

Originality/value

This study states the design of an optimized controller compared with manually tuned controller methods. Fitness functions are defined as a custom fitness function (overshoot, rise-time, settling-time and steady-state error), mean-square-error, root-mean-square-error and sum-square-error. In addition, all the simulations are performed based on a realistic simulation environment. Furthermore, the optimization process of the parameters is implemented in real-time that the proposed controller searches better parameters with real-time simulations and finds the optimal parameter online.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 18 October 2019

José-Santiago Fernández-Vázquez and Roberto-Carlos Álvarez-Delgado

This study is concerned with the perlocutionary force of emotional strategies in entrepreneurship discourse. The purpose of this paper is to determine to what extent, and under…

1238

Abstract

Purpose

This study is concerned with the perlocutionary force of emotional strategies in entrepreneurship discourse. The purpose of this paper is to determine to what extent, and under what circumstances, emotional appeals may be effective to convince the conversational partner in entrepreneurship discourse.

Design/methodology/approach

To examine the interaction between rational and emotional appeals this paper analyses a corpus formed by several examples of the “elevator pitch” genre, which have been taken from a TV programme called Tu Oportunidad (Your Chance), the Spanish counterpart of the British Dragon’s Den and the American Shark Tank. Using the information gathered in the discursive analysis of the corpus, the paper establishes a template that identifies the main rational and emotional aspects that characterize the entrepreneurial pitch. In a second stage of the research, the template is used to conduct a quantitative analysis of the persuasive influence of rational and emotional aspects.

Findings

The results of the qualitative and quantitative research show that there is a clear correlation between the propensity to finance entrepreneurial ventures and the presence of rational aspects in the entrepreneurial pitch. The lack of rational arguments determines the failure of the entrepreneur’s efforts to be persuasive, regardless of the emotional appeals that are introduced into the pitch. Emotional appeals prove to be useful to reinforce rational arguments but they are not sufficiently persuasive on their own.

Originality/value

The paper offers insight into the criteria that investors take into account in order to evaluate entrepreneurial projects, as well as on the strategies that entrepreneurs should develop to build a successful business pitch.

Details

International Journal of Entrepreneurial Behavior & Research, vol. 26 no. 3
Type: Research Article
ISSN: 1355-2554

Keywords

Article
Publication date: 1 January 1994

T. Yamada, J. Barrett, R. Doyle and A. Boetti

The use of Taguchi experimental design techniques to examine the effects of package type, solder paste type and solder reflow technique on the quality of fine pitch surface mount…

Abstract

The use of Taguchi experimental design techniques to examine the effects of package type, solder paste type and solder reflow technique on the quality of fine pitch surface mount IC package solder joints is described. In particular, the effect of the use of ceramic or plastic packages, copper or Alloy 42 leadframes, silver loaded or non‐silver loaded solder paste and infra‐red, laser or hot‐bar reflow on solder joint metallurgical structure, electrical resistance and mechanical strength is evaluated. In addition to these solder joint parameters, an associated visual inspection was used to find the best process parameters to minimise solder balling, bridging etc. and a correlation between paste contacts at placement and solder bridges after reflow was also conducted. The experiment used an L9 array to find the optimum parameters from three factors, each at three levels. An extension to the basic Taguchi array was included in the form of an outer (noise) factor to include the effect of climatic stress on the solder joints under investigation. Response tables separate out the contribution of each factor level to the mechanical strength and electrical resistance of the assemblies. By comparing the response tables before and after climatic testing it is possible to estimate the effect of each factor level on the long‐term quality of the solder joints. It is shown how Taguchi experimental design techniques can be used to minimise the number of experiments required to predict optimum solder assembly process parameters. The accuracy of the prediction is shown by the results of a confirmation run which yielded mechanical strengths very close to those predicted, both before and after highly accelerated stress testing of the solder assemblies.

Details

Soldering & Surface Mount Technology, vol. 6 no. 1
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 1 March 1993

M. Xiao, K.J. Lawless and N.‐C. Lee

12 mil pitch processing is achievable with solder paste. It may also be the limit of solder paste printing technology, mainly due to the scooping problem associated with thin…

Abstract

12 mil pitch processing is achievable with solder paste. It may also be the limit of solder paste printing technology, mainly due to the scooping problem associated with thin stencils. With decreasing pitch size, both smear and insufficiency rate increase. Tapering of stencil aperture helps thick stencil prints, but has an adverse effect on thin stencil printing. Apertures with orientation parallel to squeegee movement result in a higher print defect rate. Overall, the use of fine powders is the most effective means to meet most challenges. It helps in achieving high performance in printability, tack and non‐slump, with acceptable trade‐offs in rheology and tack time. Solder balling may be the primary drawback. The problem may be resolved by using inert reflow atmosphere or via flux chemistry improvements. A metal load of 90.5 to 91% seems to be the optimum for most properties.

Details

Soldering & Surface Mount Technology, vol. 5 no. 3
Type: Research Article
ISSN: 0954-0911

Article
Publication date: 14 June 2011

Oronzio Manca, Sergio Nardini and Daniele Ricci

The purpose of this paper is to investigate the flow and the heat transfer characteristics of a two‐dimensional rib‐roughned rectangular duct with the two principal walls…

Abstract

Purpose

The purpose of this paper is to investigate the flow and the heat transfer characteristics of a two‐dimensional rib‐roughned rectangular duct with the two principal walls subjected to uniform heat flux. In particular, the main goal is to generate friction and heat transfer data, for different values of p/e with square, rectangular, trapezoidal and triangular shape ribs for Reynolds numbers in the range between 20,000 and 60,000 and different heights and to describe the temperature and fluid‐dynamic fields around the ribs.

Design/methodology/approach

The model is constituted by a two‐dimensional duct. On the duct wall square, rectangular, triangular and trapezoidal ribs are introduced by changing different geometry ratios. Governing equations are solved numerically by means of the finite‐volume method.

Findings

Simulations show that maximum Nusselt numbers are detected in correspondence with dimensionless pitch equal to 12 and 10 for the square, trapezoidal and rectangular ribs, and triangular ones, respectively. Heat transfer rate is at most 2.45 times higher than the smooth duct, when dimensionless height is equal to 0.05, and 1.85 at a dimensionless height equal to 0.02; furthermore, the friction factor is the highest at a pitch ratio of ten for the rectangular, trapezoidal and square ribs while the triangular ones show the maximum values at a dimensionless pitch equal to 8. For Re>40,000 an asymptotic behavior is detected. Best thermal performances are provided by triangular ribs with w/e=2.0 while the rectangular ribs with w/e=2.0 present the lowest friction factor values. Local Nusselt number profiles reveal that the maximum values are detected from three to five times the rib height from the downstream turbulator. Finally, temperature fields and stream function contours are given in order to visualize the temperature distribution and flow pattern in presence of d‐type and k‐type roughness behavior also for triangular ribs.

Originality/value

The paper investigates evaluation of temperature and velocity fields thermal and fluid‐dynamic behaviors (in terms of average and local Nusselt number profiles and friction factors ones) of roughned ducts with different shapes, heights and aspect ratios of ribs in turbulent regime. The thermo‐physical properties of fluid are assumed to be dependent on temperature. The paper is useful to thermal designers.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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