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1 – 10 of 71R. Le Goff Latimier, B. Multon and H. Ben Ahmed
To foster the grid integration of both electric vehicles (EV) and renewable generators, the purpose of this paper is to investigate the possible synergies between these players so…
Abstract
Purpose
To foster the grid integration of both electric vehicles (EV) and renewable generators, the purpose of this paper is to investigate the possible synergies between these players so as to jointly improve the production predictability while ensuring a green mobility. It is here achieved by the mean of a grid commitment over the overall power produced by a collaborative system which here gathers a photovoltaic (PV) plant with an EV fleet. The scope of the present contribution is to investigate the conditions to make the most of such an association, mainly regarding to the management strategies and optimal sizing, taking into account forecast errors on PV production.
Design/methodology/approach
To evaluate the collaboration added value, several concerns are aggregated into a primary energy criterion: the commitment compliance, the power spillage, the vehicle charging, the user mobility and the battery aging. Variations of these costs are computed over a range of EV fleet size. Moreover, the influence of the charging strategy is specifically investigated throughout the comparison of three managements: a simple rule of thumb, a perfect knowledge deterministic case and a charging strategy computed by stochastic dynamic programming. The latter is based on an original modeling of the production forecast error. This methodology is carried out to assess the collaboration added value for two operators’ points of view: a virtual power plant (VPP) and a balance responsible party (BRP).
Findings
From the perspective of a BRP, the added value of PV-EV collaboration for the energy system has been evidenced in any situation even when the charging strategy is very simple. On the other hand, for the case of a VPP operator, the coupling between the optimal sizing and the management strategy is highlighted.
Originality/value
A co-optimization of the sizing and the management of a PV-EV collaborative system is introduced and the influence of the management strategy on the collaboration added value has been investigated. This gave rise to the presentation and implementation of an original modeling tool of the PV production forecast error. Finally, to widen the scope of application, two different business models have been tackled and compared.
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Helmi Aloui, Amina Ibala, Ahmed Masmoudi, Mohamed Gabsi and Michel Lécrivain
The purpose of this paper is to propose improvement of the generation capability of a claw pole alternator with DC excitation in the stator (CPAES) using analytical investigation…
Abstract
Purpose
The purpose of this paper is to propose improvement of the generation capability of a claw pole alternator with DC excitation in the stator (CPAES) using analytical investigation based on a dedicated reluctant model.
Design/methodology/approach
The paper analyzes the effects of geometry and material transformations of the magnetic circuit on the generation capability of the CPAES as well as the reduction of claw‐claw leakage flux by inserting permanent magnets in between adjacent claws.
Findings
The generation capability could be improved considering the proposed geometry and material changes of the magnetic circuit of the CPAES. The inclusion of permanent magnets in between adjacent claws offers an increase of the alternator generation due to the reduction of the claw‐claw leakage flux.
Research limitations/implications
The research should be extended by building a new prototype of the CPAES in order to compare analytical results and experimental ones.
Practical implications
A new concept with no brush‐ring for excitation and an improvement of the generation capability of the alternator make the CPAES an interesting candidate especially in large‐scale production applications such as the automotive industry.
Originality/value
The paper proposes a new alternator topology called claw pole alternator with DC excitation in the stator (CPAES) and an analytical approach to improve the generation capability of such a concept, which represents a crucial challenge in electric generation systems especially in automotive applications.
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Taehee Kim, Hyomin Seo, Min Cheol Kim and Kyungro Chang
Boosting productivity in the service sector is a key priority for promoting long-term growth. To have customers perform certain tasks normally undertaken by employees is an…
Abstract
Boosting productivity in the service sector is a key priority for promoting long-term growth. To have customers perform certain tasks normally undertaken by employees is an important means to improving productivity. Technological innovation has influenced business practices for several decades and many service firms, including sports service firms, are now utilising technology extensively to reduce the use of labour. This study investigates how the user's perception of technology-based self-service (TBSS)affects customer productivity and how the customer productivity evaluated by TBSS influences the customer's intentions to reuse in relation to a virtual golf simulator - a successful and seriously played game in Korea.
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V. Mester, F. Gillon and P. Brochet
The paper highlights the process of electric vehicles optimal design as an inverse problem and presents the global constrained optimization as the best way to solve it.
Abstract
Purpose
The paper highlights the process of electric vehicles optimal design as an inverse problem and presents the global constrained optimization as the best way to solve it.
Design/methodology/approach
The electric vehicle optimal design is carried out by a new approach. It consists an electric vehicle design model managed by constrained optimization techniques. It includes sizing models for all drive train components and a vehicle dynamic model build in a new “design way” as an energy‐based model using the response surface methodology. The sensitivity of first simple sizing models can be evaluated by the experimental design method, giving information about the most important part of the model that must be improved.
Findings
The result shows the superiority of the constrained optimization technique that treats simultaneously the global optimization and the model adjustment. This method of simultaneous resolution is much more powerful than the successive resolution of each subproblem. The proposed “design approach” used for electric vehicle optimal design offer a large potential in the field of the complex systems design.
Originality/value
The electric vehicle design process is treated on a vehicle design model based on a design approach. It allows determining the drive train components specifications for imposed vehicle performances, taking into account the dynamic model of the vehicle and all components interactions. Furthermore, considering fine components sizing models, the components can be sized taking into account the whole system behavior in an optimal global design.
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Jens Rowold, Sabine Hochholdinger and Jan Schilling
Although proposed from theory, the assumption that career‐related continuous learning (CRCL) has a positive impact on subsequent job performance has not been tested empirically…
Abstract
Purpose
Although proposed from theory, the assumption that career‐related continuous learning (CRCL) has a positive impact on subsequent job performance has not been tested empirically. The present study aims to close this gap in the literature. A model is derived from theory that predicts a positive impact of CRCL, learning climate, and initial job performance on consequent job performance. In addition, CRCL is hypothesized to mediate the impact of learning climate on final job performance.
Design/methodology/approach
Implementing a longitudinal approach, this model was tested empirically in a call center context. Within the first year of their respective career, multiple source data were gathered from employees about their formal CRCL activities, their initial performance, as well as their perception about learning climate.
Findings
Results indicated that CRCL predicted final job performance and mediated the impact of learning climate on final job performance. A total of 28 percent of final job performance was explained by the proposed model, highlighting the importance of CRCL for organizational contexts.
Practical implications
The results of this study support the notion that CRCL programs are highly useful for both employees and organizations.
Originality/value
For the first time, the impact of CRCL on job performance is demonstrated empirically.
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Carlos Guilherme da Costa Neves, Aly Ferreira Flores Filho, Mateus Felipe Goettems and Pablo Augusto Machado Borges
The purpose of this paper is to simulate a pseudo direct drive (PDD) by using permanent magnet arrays.
Abstract
Purpose
The purpose of this paper is to simulate a pseudo direct drive (PDD) by using permanent magnet arrays.
Design/methodology/approach
A 2D finite element model of the PDD was built. The static magnetic torque on air-gaps was obtained by Coulomb’s virtual work method using Ansys Maxwell software. To simulate the relative movement between input rotor and output rotor, two movement bands were applied.
Findings
The PDD’s torque relation was proved. The PDD simulated presents low cogging torque.
Practical implications
The manufacturing steps and materials applied in a construction of a coaxial magnetic gear, PDD’s main component, are presented.
Originality/value
The value of this paper is to present the numerical techniques applied to simulate a PDD and the manufacturing steps and materials applied in a construction of a coaxial magnetic gear.
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The purpose of this paper is to investigate the influence of end‐effect and cross‐coupling on the torque‐speed characteristics of switched flux permanent magnet (SFPM) machines.
Abstract
Purpose
The purpose of this paper is to investigate the influence of end‐effect and cross‐coupling on the torque‐speed characteristics of switched flux permanent magnet (SFPM) machines.
Design/methodology/approach
The torque‐speed characteristics are predicted using two different methods. These are direct and indirect finite element methods, at different cross‐coupling levels, namely, full cross‐coupling on both PM flux linkage and dq‐axis inductances, partial cross‐coupling on the PM flux linkage only and without cross‐coupling.
Findings
The influence of the cross‐coupling on dq‐axis inductances of the studied machine is relatively small. However, it is more significant on the PM flux linkage. Therefore, the partial cross‐coupling model, which is much easier and faster, exhibits almost the same accuracy as the full cross‐coupling model. Furthermore, the end‐effect causes a large reduction in torque‐speed characteristics. However, such a reduction is more significant in the flux weakening operation region.
Originality/value
This is the first time that the influence of end‐effect of SFPM machines on the torque‐speed characteristics, especially in flux weakening region, and on the dq‐axis inductances has been investigated.
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The purpose of this paper is to compare the performance of conventional, novel E‐ and C‐core switched‐flux permanent magnet (SFPM) machines having different combinations of stator…
Abstract
Purpose
The purpose of this paper is to compare the performance of conventional, novel E‐ and C‐core switched‐flux permanent magnet (SFPM) machines having different combinations of stator and rotor pole numbers, with particular reference to the conductor and magnet eddy current loss and iron loss.
Design/methodology/approach
The electromagnetic performance of the analysed machines is compared using the finite element (FE) analysis.
Findings
Both iron and conductor eddy current losses increase with the rotor pole number, while the 11‐ and 13‐rotor pole machine always exhibit lower magnet eddy current loss than those of the 10‐ and 14‐rotor pole machines, respectively. The E‐ and C‐core machines use half the number and volume of magnets and also exhibit higher efficiency than those of the conventional SFPM machine.
Originality/value
Investigation of the influence of stator and rotor pole combinations on the performances of conventional, novel E‐ and C‐core SFPM machines, include losses and efficiency.
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Jungang Wang and Zhiliang Zeng
The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation…
Abstract
Purpose
The purpose of this study is to propose a new magnetic gearing device and the proposed transmission model can be applied in the field of wind power and wave energy generation gearboxes.
Design/methodology/approach
A novel radial differential field-modulated two-stage magnetic gear is introduced, using a unique radial differential linkage to integrate two single-stage magnetic gears. This design incorporates a magnetic isolation ring to enhance transmission efficiency by minimizing magnetic interference and preventing power circulation. The two-stage modulating ring rotor operates synchronously via a connecting bridge, ensuring system stability and efficiency. This configuration not only boosts the gear ratio but also maintains a compact structure, improving power density and efficiency. Leveraging the magnetic field modulation and differential transmission, a finite element model of this gear is developed and its electromagnetic performance is analyzed.
Findings
The torque density of the new radial differential field-modulated two-stage magnetic gear has increased by 44.97% compared to the traditional tandem two-stage magnetic gear. It achieves a high transmission ratio of 64 and maintains comparable power density, indicating strong torque transfer capabilities suitable for low-speed, high-torque applications. During steady-state operation, the torque pulsation difference between the two stages is minimal, ensuring stable working torque.
Social implications
This research not only propels the forefront of magnetic gear technology through heightened efficiency and streamlined design but also bears profound societal significance in fostering sustainable energy paradigms. By facilitating superior energy conversion efficiencies in wind turbines and wave energy converters, it plays a pivotal role in mitigating carbon emissions and accelerating the global pivot towards cleaner, renewable energy landscapes.
Originality/value
A magnetic gear transmission device is proposed, which can achieve high power density and large transmission ratio at the same time, and this study provides a useful reference for the design optimization of new high-performance multistage magnetic gears.
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Ali Moghimi, Mahmood Hosseini Aliabadi and Hassan Feshki Farahani
This paper aims to introduce a new structure for coaxial magnetic gears.
Abstract
Purpose
This paper aims to introduce a new structure for coaxial magnetic gears.
Design/methodology/approach
The study discusses the design and electromagnetic modeling of a triple-speed coaxial magnetic gear (TSCMG) for three different levels of torques in special applications such as wind energy conversion and electrical vehicles. The proposed TSCMG consists of inner, middle and outer rotor, which has one rotor more than its conventional counterpart. The suggested TSCMG’s related equations such as transform ratio and torque are calculated, then TSCMG is simulated in a finite element environment. A comprehensive study has been done on TSCMG, and results are compared with two other magnetic gears with the same volume but two speeds.
Findings
The obtained results show that the proposed structure for TSCMGs is significantly practical and applicable in higher ranges of torques. Finally, an experimental TSCMG is prototyped to verify the results.
Originality/value
The achievements are excellent and confirm that TSCMG can be used as powerful equipment in a wide range of application like permanent wind turbines to generate electricity in 24 h per every single day.
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