Comparison of motor stator teeth built of soft magnetic composite and laminated silicon steel sheets in an axial flux permanent magnet synchronous machine

This paper compares the iron losses generated by the concentrated excitation windings for the axial flux permanent magnet synchronous machine stator core elements constructed with laminated silicon steel sheets and soft magnetic composites. The two types of eddy current losses for laminated silicon steel sheets are taken into account. A 3D nonlinear finite element method in the time domain is used to calculate all flux density distributions for various frequencies and different magnitudes. Experimental measurements are also performed to validate the 3D model

Torque analysis on a double rotor electrical variable transmission with hybrid excitation

An electrical variable transmission (EVT) can be used as a power splitting device in hybrid electrical vehicles. The EVT analyzed in this paper is a rotating field electrical machine having two concentric rotors. On the outer rotor, permanent magnets (PMs) are combined with a dc-field winding, being the first implementation of its kind. The magnetic field in the machine as well as the electromagnetic torque on both rotors are a function of the q- and d-axis currents of the stator and inner rotor, as well as the dc-field current. To describe and fully understand this multiple-input multiple-output machine, this paper gives an overview of the influence of the different current inputs on the flux linkage and torque on both rotors. Focus is given to the hybrid excitation in the d-axis by combining the dc-field current and the alternating currents. This has the advantage compared to other EVT topologies that unwanted stator torque can be avoided without stator d-axis current flux weakening. Results of the analysis are presented by means of the torque to current characteristics of a double rotor PM-assisted EVT, as well as the torque to current ratios. The machine characteristics are finally experimentally verified on a prototype machine

Experimental investigation of direct contact baseplate cooling for electric vehicle power electronics

An experimental setup has been built to investigate the thermo-hydraulic performance of the direct contact baseplate cooling technique for power electronics in electric vehicles, to improve the design and to validate the modelling of this technique. The setup consists of an electrical heater to emulate the heat dissipation of the power electronics and which is cooled by a 60/40% mixture by mass of water-glycol. It is equipped with a flow rate sensor, absolute and differential pressure sensors and temperature measurements at the inlet, outlet and baseplate over the channel length, to determine the performance parameters used in the comparison: thermal resistance and pumping power. Three fluid inlet temperatures, four power levels and four flow rates have been tested for three channel heights (1.5mm, 3mm and 7.6mm). Increasing the fluid temperature and/or heating power, results in a lower thermal resistance and pumping power, due to a lower viscosity of the fluid. The performance of the 1.5mm and 7.6mm channel was found to be quite similar, while the 3mm channel results on average in a 5.8% lower thermal resistance compared to the other two channel heights. The heat transfer in terms of the Nusselt number was also evaluated in function of the Reynolds number. By analyzing the hydraulic and thermal entrance lengths it could be concluded that the flow in all measurements is simultaneously developing. A comparison with two correlations from scientific literature for simultaneously developing flow did not show a good agreement, possibly due to the specific inlet and outlet effect, which is more pronounced for a bigger channel height than a smaller channel height

A holistic DC link architecture design method for multiphase Integrated Modular Motor Drives

This article describes a holistic DC link architecture design method that considers the end-application of the drive and its corresponding constraints e.g. the maximum battery ripple current for a battery-supplied inverter. Also, the levers that are available to comply with the design criteria are presented e.g. the use of interleaved carrier waves. This holistic approach will result in a feasible and performant Integrated Modular Motor Drive from an application point of view. Finally, a platform is presented that was developed for feasibility and performance assessment of various DC link architectures obtained from the holistic design approach. The platform comprises a fifteen phase integrable modular motor drive for an Axial Flux Permanent Magnet Synchronous Machine. It allows non-intrusive reconfiguration of the DC link architecture and implementation of various control strategies and interleaved PWM schemes

Desiring and critiquing humanity/ability/personhood : disrupting the ability/disability binary

The authors take up the challenge of Goodley and Runswick-Cole’s call to dismantle the ability/disability binary such that those now called ‘disabled’ can unproblematically join the ranks of those who will be counted as human. Using the methodology of collective biography, the six authors explore their own memories of becoming abled, and find in those memories a similar pattern of desire for, and critique of, humanness that Goodley and Runswick-Cole found in the participants in their own study, participants who were categorised as intellectually disabled. We turn to post philosophies to further develop the vocabularies through which the meaning of human can be expanded to include those who are currently viewed as less-than-human or other-to-human in their difference from the norm. Points of interest: - In this article the authors use the research method of ‘collective biography’ to explore their first memories of how they became able, and were recognized as normal and human. - We work with childhood photos to help open up our memories. - We challenge the taken-for-granted division between the categories normal/abnormal, able/disabled. - We argue that everybody is different, and that we all change and become able in different ways. - We are all vulnerable and we all desire to belong in the same world, irrespective of the categories we are placed in

Quality assessment of a 2D FE based lumped parameter electric motor thermal model using 3D FE models

This paper presents an advanced thermal lumped parameter model (LPM) for a switched reluctance motor for which the quality of the results is verified with a 3D finite element (FE) simulation. An advanced lumped parameter model is proposed, which extracts a 2D LPM from a 2D FE simulation in FEMM and extends this 2D LPM into 3D based on the regular LP techniques. The assumptions and simplifications in de 3D LPM are verified with a 3D FE model by comparing the simulated average and maximum component temperatures of the models. The comparison shows a maximum deviation of 7.1% on the average temperature and 10.9% on the maximum temperature. It is concluded that the proposed advanced 3D LPM is an efficient and sufficiently accurate method against 3D FEM

Field oriented control for an induction-machine-based electrical variable transmission

An electrical variable transmission (EVT) is an electromagnetic device with dual mechanical and electrical ports. In hybrid electric vehicles (HEVs), it is used to split the power to the wheels in a part coming from the combustion engine and a part exchanged with the battery. The most important feature is that the power splitting is done in an electromagnetic way. This has the advantage over mechanical power splitting devices of reduced maintenance, high efficiency, and inherent overload protection. This paper gives a conceptual framework on how the torque on both rotors of the EVT can be simultaneously controlled by using a field-oriented control (FOC) scheme. It describes an induction-machine-based EVT model in which no permanent magnets are required, based on classical machine theory. By use of a predictive current controller to track the calculated current reference values, a fast and accurate torque control can be achieved. By selecting an appropriate value for the flux coupled with the squirrel-cage interrotor, the torque can be controlled in various operating points of power split, generation, and pure electric mode. The conclusions are supported by simulations and transient finite-element calculations

The small wind turbine field lab extensive field tests for small wind turbines

This paper describes the research possibilities at the Small Wind Turbine Field Lab and the involved research groups of Ghent University, covering different aspects of a small wind energy system. In contrast to large and medium-sized wind turbines, small wind turbines are still plagued by relatively high production and purchase costs, and low reliability and energy yield. Furthermore, most of them have not been subjected to a field test program. Power-Link, the energy knowledge platform of Ghent University, has for three years operated a modest field test site for small wind turbines, that drew the attention of a lot of manufacturers of small wind turbines. In response, Ghent University decided to launch the Small Wind Turbine Field Lab (SWT Field Lab), to subject small wind turbines to more extensive field tests. Now not only the energy yield is tested, but also topics such as grid integration, structural strength, noise propagation, generator and drive train design and tower construction are studied. All of these parameters are correlated with meteorological data measured on-site