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Ruuskanen V.,Lappeenranta University of Technology | Nerg J.,Lappeenranta University of Technology | Rilla M.,Visedo Oy | Pyrhonen J.,Lappeenranta University of Technology
IEEE Transactions on Industrial Electronics | Year: 2016

Fast methods to estimate iron losses of the permanent magnet traction motor during the drive cycle of the electrical vehicle are compared. The methods use the iron loss information calculated by a finite-element analysis as a function of rotational speed both at no load and with a short-circuited stator to take into account the variable frequency and field weakening of the traction motor. The effect of iron losses on the optimal current components, providing the maximum efficiency, is studied. Several methods yield a good accuracy even based on the no-load iron loss only, but the accuracy can be improved especially in deep field weakening by including the short-circuit iron loss information in the analysis. © 1982-2012 IEEE. Source


Lindh P.,Lappeenranta University of Technology | Heikkinen J.,Lappeenranta University of Technology | Kurvinen E.,Lappeenranta University of Technology | Pyrhonen J.,Lappeenranta University of Technology | Naumanen V.,Visedo Oy
International Review of Electrical Engineering | Year: 2013

The paper addresses the embedding parameters of permanent magnets and their effects on the performance of an interior permanent magnet radial-flux machine. Special attention is paid to the embedding depth of the permanent magnets and the design of the magnet pockets in the rotor laminations to ensure the optimal mechanical and electromagnetic performances of the machine. There are hollow spaces on the sides of the magnets to prevent permanent magnet leakage flux and to minimize mechanical stresses in the lamination steel. Smart interaction between the mechanical and electrical engineering designs is needed to streamline the design process. By considering these design approaches, a rough estimation can be obtained for an appropriate rotor design. To this end, the study seeks solutions to the height of the rotor steel bridge and the shape of the hollow space that are viable both from the mechanical and electrical aspects. The mechanical stresses and the electromagnetic forces are calculated by Finite Element Analyses (FEA). The effects of the embedding depth of the magnets on torque, efficiency, and mechanical stresses are reported. The results are used to provide guidelines on the permanent magnet traction motor (PMTM) design. © 2013 Praise Worthy Prize S.r.l.-All rights reserved. Source


Pyrhonen J.,Lappeenranta University of Technology | Lindh P.,Lappeenranta University of Technology | Polikarpova M.,Lappeenranta University of Technology | Kurvinen E.,Lappeenranta University of Technology | Naumanen V.,Visedo Oy
Applied Thermal Engineering | Year: 2015

Axial-flux machines tend to have cooling difficulties since it is difficult to arrange continuous heat path between the stator stack and the frame. One important reason for this is that no shrink fitting of the stator is possible in an axial-flux machine. Using of liquid-cooled end shields does not alone solve this issue. Cooling of the rotor and the end windings may also be difficult at least in case of two-stator-single-rotor construction where air circulation in the rotor and in the end-winding areas may be difficult to arrange. If the rotor has significant losses air circulation via the rotor and behind the stator yokes should be arranged which, again, weakens the stator cooling. In this paper we study a novel way of using copper bars as extra heat transfer paths between the stator teeth and liquid cooling pools in the end shields. After this the end windings still suffer of low thermal conductivity and means for improving this by high-heat-conductance material was also studied. The design principle of each cooling system is presented in details. Thermal models based on Computational Fluid Dynamics (CFD) are used to analyse the temperature distribution in the machine. Measurement results are provided from different versions of the machine. The results show that significant improvements in the cooling can be gained by these steps. ©2014 Elsevier Ltd. All rights reserved. Source


Nerg J.,Lappeenranta University of Technology | Rilla M.,Visedo Oy | Ruuskanen V.,Lappeenranta University of Technology | Pyrhonen J.,Lappeenranta University of Technology | Ruotsalainen S.,Helsinki Metropolia University of Applied Sciences
IEEE Transactions on Industrial Electronics | Year: 2014

The design process of direct-driven permanent-magnet (PM) synchronous machines (PMSMs) for a full electric 4 × 4 sports car is presented. The rotor structure of the machine consists of two PM layers embedded inside the rotor laminations, thus resulting in some inverse saliency, where the q-axis inductance is larger than the d-axis one. An integer slot stator winding was selected to fully take advantage of the additional reluctance torque. The performance characteristics of the designed PMSMs were calculated by applying a 2-D finite-element method. Cross saturation between the d- and q-axes was taken into account in the calculation of the synchronous inductances. The calculation results are validated by measurements. © 1982-2012 IEEE. Source


Patent
Visedo Oy | Date: 2014-01-03

A capacitor module includes a capacitor element (

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