The paper deals with an approach to reduce the detent force of double-sided flat linear permanent magnet synchronous machines (PMSMs). The study is initiated by a finite element analysis (FEA)-based investigation of the detent and normal forces of a conventional concept with aligned PM rows mounted on both mover sides. It is found that while it exhibits a quasi-null normal force, the concept is penalized by a huge detent force. An attempt to reduce such a drawback consisting in shifting the PM rows is proposed. Its effectiveness in reducing the detent force is demonstrated by FEA. However, it leads to a remarkable increase of the normal force. In order to minimize this latter, a second design approach consisting in a unilateral extension of both sides of the stator magnetic circuit, is proposed. It is shown that selecting 50% for both PM shift-to-the pole pitch and stator extension length facing the air gap-to-the pole pitch ratios yields acceptable peak-to-peak values of the detent and normal forces. The force production of the resulting machine is then evaluated and compared to the conventional concept one. In spite of the minimization of the force ripple, its mean value is limited to 50%. An approach consisting in a reconfiguration based on the star of slots of the armature in both stator sides, is proposed and assessed by FEA. As a result, an increase of the mean force as well as a reduction of the force ripple are gained.
This paper presents a novel approach towards modelling energy usage of a high-performance, motorsport-purposed electric motorcycle (eBike) under racing use conditions. While the energy usage is assessed, the simulation robustness is also considered as it will confirm that the chosen modelling approach has a high degree of versatility. The presented research work showcases the presented modelling approach applied as a software model, indicates the chosen methodology for acquiring the required telemetry data and finally presents the results and related conclusions and interpretations and their meaning to the field of expertise and the related project.
A common approach to enhance the overall efficiency of an electric driven vehicle is to use a double motor concept. In the hereby presented research project TIOM (Two In One Motor) two different electric motors are used for traction, the compressor of the air conditioning (AC) system and the air compressor for the pneumatic systems in a public bus used in urban and suburban traffic. The main research questions in the following paper are first how the TIOM concept can be adapted to urban busses and second if the developed operation strategy leads to higher efficiencies. For this purpose a use case was defined and modelled with Dymola. A typical driving cycle was defined as use scenario. The model contains an operation strategy that can select between 16 different operation modes for the two motors based on the efficiencies of the motors, the torque requirements, the rotation speed of the wheel and the rotation speed range of the compressors. As a result, the energy consumption for the use case is evaluated and compared to a bus with a conventional motor concept with one large motor.
The permanent magnet linear machines with primary excitation (PE-PMLM) is a special type of linear machine derived from traditional permanent magnet linear machines, which has the advantages of high thrust force density, high efficiency, high precision and high reliability. In the field of long-stroke direct-drive linear motion, PE-PMLM exhibits its unique performance and cost advantages. This paper reviews and summarizes the research status and development trend of the PE-PMLM. First, the thrust force generation mechanism of the PE-PMLM is revealed based on the flux modulation theory. Second, the technical points and research progress of various kinds of PE-PMLM are reviewed. Third, comprehensive performances of all kinds of PE-PMLM are compared and analysed. Finally, the future development trend is discussed.
A Power Take-Off (PTO) is responsible to convert wave to electrical power and is one of the core sub-systems of any Wave Energy Converter (WEC). As result, assessing the PTO performance is one of the key aspects of the WEC design and, looking at the optimization of all WEC subsystems, it directly impacts the LCOE assessment and the commercialization of the technology. To address this need, it is crucial to approach WEC modeling with the awareness of the different techniques. The paper presents part of the results of the IMAGINE R&D program developed with the support of European Union's H2020 research and innovation programme. This project is aimed at the design and test of a novel PTO drive intended for a range of WEC configurations. In particular, the paper presents a complete simulation platform, which allows realistic simulations of the performance of a 250 kW modular electro-mechanical generator (EMG) when coupled to an oscillating wave surge converter (OWSC) device. This model is compared to a corresponding simplified model more suitable for real-time (RT) hardware-in-the-loop (HIL) testing. A comparison between the two is provided as fundamental check to guarantee that the simulated environment is as similar as possible to the real-space and hence to validate the product maturity even though with a certain level of simplification.
This study proposes a short term forecasting of solar irradiation with multi horizons in the north-west of Senegal. The multilayer artificial neural network (ANN), based on the Levenberg Marquardt algorithm and the meteorological data are used. The latter are measured in real time on the study site. The variables of interest are: mean solar irradiation, maximum temperature and measurement time; they are selected using Weka software. The forecasting horizons are: 0.5 hour, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours and 06 hours. They are proposed with the corresponding statistical criteria. The results show that, the solar energy forecasting can be extended over a six-hour horizon with a correlation coefficient of 0.97 and root mean square error of 0.07. These results will make it possible to complete the forecasting tools in the solar energy sector in Senegal, and help investors to choose the most suitable horizons for energy forecasting in photovoltaic solar power plants.
The PWM generated by wide bandgap devices can feature a shorter rise time than in the case of standard silicon switches. The resulting harmonic content can excite the resonance frequencies of Medium-Frequency Transformers (MFTs), causing internal overvoltages during continuous operation. If ignored, this phenomenon can cause unexpectedly high electric fields in the insulation, possible partial discharges and failure of the MFT. The occurrence of these overvoltages is determined by the high-frequency response of the MFT and it is significantly influenced by the winding topology. In this paper, the choice of conductor type and possible resulting topologies are analyzed. A multi-layer litz winding and a concentric disk foil winding are compared. The trade-off among the conductors used in the two topologies is followed by the analysis of the voltage distribution in the winding by the multi-conductor fully-coupled transmission line method. The continuous disk foil winding MFT does not present internal overvoltages and is therefore a preferable option in this respect. However, in light of the trade-off between litz and foil wire, the global optimal solution will be case-dependent relying on the design requirements, which concur in determining the best design choice.
This paper presents a practical implementation of synchronous PWM modulation algorithm for an induction motor field oriented control powered by a DC/AC inverter and implemented on a low-cost microcontroller, the ATSAM3X8E. In particular, a simple algorithm, capable to calculate automatically an optimized set of frequency modulation indexes will be presented. Hysteresis bands are also introduced in the algorithm in order to avoid multiple changeovers during modulation index transitions. Experimental tests and their results will be shown and discussed, highlighting the benefits of the present algorithm, such as reduction of current harmonic content, reduction of current ripple and, consequently, reduction of power losses in the IM drive.
This paper presents a piezoelectric harvester prototype with liquid tip mass for frequency tuning. The use of a liquid mass makes it possible to limit mechanical stress inside the harvester, with a resonance frequency reduction comparable to a solid mass. A mathematical model of the water sloshing in the tip container, which makes it possible to predict natural frequencies of a harvester with liquid mass, is presented. Such analytical model can be used for the harvester tuning to low-frequency vibration sources. Mathematical predictions are in good agreement with experimental results obtained from the harvester prototype. As an example of practical application is considered: energy harvesting from bicycle vibrations.
The high diffusion of electric vehicles is evidenced by every sector magazine or by the catalog of all the manufacturers inserting incessantly new models. But what are the user's most hidden reactions to the new world of vehicles? Is the user ready for the fifth level of automation (fully automatic driving and absence of the driving position)? The purpose of this paper is to present and discuss the psychological aspects that influence the adoption of electric vehicles by users and beyond. Topics such as the egg and chicken paradox (electric vehicles and charging stations, who was born first) but also performance anxiety (range anxiety) will be addressed. Contradictions and irony will characterize this paper.
This paper presents a comparative simulation analysis of an Interior Permanent Magnet Synchronous Machine (IPMSM) performance once fed by a traditional three-phase two-level inverter and then using a three-phase five-level Cascaded H-Bridges Multilevel Inverter (CHBMI). For this purpose, an enhanced mathematical model of the IPMSM, that take into account simultaneously saturation, cross-coupling, spatial harmonics and iron loss effects, has been employed. Furthermore, two different PWM modulation strategies have been considered. The study was conducted for several working conditions, evaluating the impact of CHBMI adoption on the IPMSM performance in terms of improved efficiency and torque ripple reduction.
Multi-energy networks are becoming a leading research subject in the last years, particularly, with the accelerating emergence of renewable resources into the energetic system. Decoupling this problem into several single-vector networks results in a sub-optimal solution. However, this approach comes up against a great technological complexity, from the design of each of the components necessary for such a hybrid network to their modeling and the global management of the whole. In this work, we propose coupled electrical and thermal networks, with an energy hub integrating electrochemical and thermal storage systems, and conversion systems: Heat To Power and Power To Heat. To achieve this, a modeling of the different physical subsystems and a management of the whole system using Model Predictive Control (MPC) are investigated. Finally, a comparison of the two configurations without and with coupling is conducted to evaluate the impact of such a multi-energy network.
The popularity of electric vehicles is evidenced by the broad range of manufacturers presenting new models of plug-in hybrid and battery vehicles. However, the success of the revolution or, rather, the rebirth of electric vehicles, is hanging by a thread, as it lacks the involvement of a large number of users, and many psychological mechanisms hinder it. What are users’ true feelings about this new world of vehicles? Are people ready for the fifth level of automation, i.e., fully automatic driving and the absence of the driving position? The purpose of this paper is to present and discuss the psychological aspects that influence the adoption of electric vehicles. Topics such as the chicken and egg paradox (electric vehicles and charging stations) and performance anxiety (regarding, e.g., range) are addressed. This review is characterized by contradictions and irony.
The development of power-assisted bikes (ebike) is of growing interest because of their economic and environmental advantages. The present work deals with the sizing optimization of a charging station for ebike based on particle swarm optimization. It is based on the consumption profile of ebike batteries, solar and wind power, installation, replacement and maintenance costs of components. In a first step, the consumption profile of the ebike batteries is determined using the second order non-linear electrothermal model. Then, the solar and wind data over one year are used to determine the availability of energy at the implementation site of the charging station. Finally, the cost is defined as an objective function, taking into account the constraints on the number of solar photovoltaic panels, the number of wind turbines, the number of storage batteries and the annual charging demand. The context of a charging station to be implemented in the Polytech Annecy campus in France is studied. The results show that the particle swarm optimization allows a cost reduction of around 56.04% compared to a sizing without optimization.
This paper investigates the potential of energetic utilization of hydrogen expansion in a fuel cell electric passenger vehicle. The expansion process is considered and evaluated from the thermodynamic side with different assumptions. The theoretical calculations are used in combination with measured data from a research fuel cell electric vehicle to calculate potential energies that are generatable with hydrogen expansion during driving. In addition, the requirements and boundary conditions for a hydrogen expander are considered and different expansion technologies are compared for their suitability for the application in a fuel cell vehicle. Finally, first results of a model of the hydrogen expansion engine in DYMOLA will be presented.
A six-phase electronic pole changing winding induction machine with 4/2-poles is discussed in this paper. The improved winding factor of the six-phase pole changing winding during high pole number operation over the conventional three-phase windings is discussed. It is also shown that when operating with the lower number of poles, due to the reduction of the spatial angular separation between the three-phase groups, the 3 rd harmonic current injection is possible and results in enhanced torque capability and an increased flux weakening region of operation. Finite Element Analysis (FEA) is used to determine the impact of pole changing and the 3 rd harmonic injection on torque ripple and also to determine the optimum 3 rd harmonic to fundamental current ratio that maximises the peak torque capability. The simulation results demonstrate the behaviour of the six-phase pole changing winding induction machine with the 3 rd harmonic injection.
A multi-cylinder floating structure with conventional catenary mooring lines is presented for supporting a 10 MW Wind Turbine (WT). A design-oriented solution method accounting for the coupled dynamics of the floating structure in the frequency domain is presented and the corresponding RAO's are calculated. The hydrodynamic characteristics are determined using matched axisymmetric eigenfunction expansions. A reduced order model provides the linearized loading contributed by the WT (gravitational, inertial and aerodynamic). In addition, time domain coupled hydro-servo-aero-elastic simulations of the floating structure are performed considering wave excitation described by a white noise spectrum whereby the effective RAO's are computed from the corresponding time signals. Comparison between the two methods is performed at the RAO's level for representative wind speeds and wave heading angles.
As an alternative to stationary Coupled Heat- and Power (CHP) systems, Fuel Cell Electrical Vehicles (FCEVs) can be used as mobile electricity and heat suppliers of buildings to cover their energy demand. In this work the combined useage of thermal and electrical energy supplied by FECVs to an all-electric 8-party appartment is investigated using simulation. The analysis focuses on the environmental condition, when solar and wind power generation is very low or zero at the same time (ger.: “Dunkelflaute”).
This paper investigates the impact of using wide bandgap (WBG) technology-based bidirectional interleaved HV DC/DC converters on the performance of battery electric vehicles (BEVs), An existing electric vehicle is upgraded using off-the-shelf components. There are a variety of batteries, high voltage (HV) DC/DCs, inverters, electric motors, transmissions, etc., available off-the-shelf; hence, numerous possible combinations can be formed, which make the optimal component selection process more complicated through analytical methods. In this paper, a multiobjective genetic algorithm (MOGA) is adopted to minimize the electric energy consumption by improving drivetrain efficiency based on the optimal variant selection of the components. It is found from the virtual simulation framework in MATLAB/Simulink® that overall, there is a 9.2% reduction in the energy consumption over a given driving cycle, i.e., Worldwide Harmonized Light Vehicles Test Procedure-3a (WLTP3a). To this end, the drivetrain performance in terms of acceleration time from 0–90 km/h is also improved by 10.2%, while the efficiency is improved by 1.5% compared to the conventional e-drivetrain.
This paper presents a multiphysics modelling and real-time simulation of PMSMs. The study includes electromagnetic modelling, thermal modelling, and finally, a real-time reduced-order model simulation is developed. The resulting model is capable of online estimation of machine parameters and temperature. The results have been compared with dedicated software and a good agreement has been noticed.
