Janne KeränenVTT Technical Research Centre of Finland, Tampere, Finland · Mobility and transport
Janne Keränen
D.Sc.
About
37
Publications
15,544
Reads
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245
Citations
Citations since 2017
Introduction
Senior Scientist at VTT Technical Research Centre of Finland, Mobility and Transport, Electrical powertrains and storage.
Our website: https://www.vttresearch.com/en/ourservices/electric-vehicles-and-vehicles-systems
Additional affiliations
January 2012 - April 2022
Position
- Principal Investigator
Description
- Research topics: computation methods, finite element simulations, data-driven models, surrogate models, electromagnetics, electrical machines, electrical powertrains, open source tools.
May 1999 - December 2011
Position
- Reseacher
Description
- M.Sc. and D.Sc. research topics: numerical computation of electromagnetic wave problems, developing numerical methods, and mathematical modeling of electromagnetics. Further, lecturing advanced courses of antennas and being assistant in numerous courses.
Education
June 2004 - March 2011
June 2000 - September 2001
Publications
Publications (37)
A transient model of an induction machine (IM) is developed in this work using an artificial neural network (ANN) surrogate model. The model is suitable to be used for direct-on-line IMs. The finite-element (FE)-based model of IM is used to generate the training, validation, and testing datasets. Different inputs and model configurations are invest...
Rotor bars are one of the most failure-critical components in induction machines. We present an approach for developing a rotor bar fault identification classifier for induction machines. The developed machine learning-based models are based on simulated electrical current and vibration velocity data and measured vibration acceleration data. We int...
Electric retrofitting (e-retrofitting) is a viable option for accelerating the renewal of heavy duty vehicle fleets to reduce the related emissions. We introduce a simulation-based assessment of e-retrofitting strategies for heavy-duty vehicles. Our simulation tool, an electric vehicle fleet simulation toolbox, comprises three modules, namely drivi...
Machine learning and artificial neural networks have shown to be applicable in modeling and simulation of complex physical phenomena as well as creating surrogate models trained with physics-based simulation data for numerous applications that require good computational performance. In this article, we review widely the surrogate modeling concept a...
We study the structural topology optimization (TO) of a high-speed electrical machine rotor. The electromagnetic design of the machine is taken as a starting point for the optimization. The optimization design space is chosen to be the area where the magnetic flux does not exceed the level of 0.6 T. The structural TO problem is formulated using mat...
HPC-Europa3 reseach project
We study the topology optimization (TO) of an 8/6 switched reluctance motor rotor in terms of torque and mass. Together with
additive manufacturing, topology optimization offers disruptive possibilities in electrical machine design. We investigate how sensitive the TO is to the problem setup by varying mesh density, material definitions and initial...
Purpose – The purpose of this paper is to report on the developments in manufacturing soft magnetic materials using laser powder bed fusion (L-PBF).
Design/methodology/approach – Ternary soft magnetic Fe-49Co-2V powder was produced by gas atomization and used in an L-PBF machine to produce samples for material characterization. The L-PBF process p...
Additive manufacturing (AM) opens up new design possibilities for electrical machines. For example in [1], a low torque ripple 6/4 switched reluctance motor (SRM) has been produced by 3D printing a structure which would have been virtually impossible to manufacture with traditional methods. However, to fully unlock the potential of AM in electrical...
NAFEMS 2019 Conference presentation:
Topology Optimization of 3D Printed Switched Reluctance Motor
https://www.nafems.org/events/nafems/2018/am18/
https://nafems.fromsmash.com/AdditiveManufacturing
Additive manufacturing opens up new opportunities in the design and manufacturing of electrical machines. Maximizing the potential of these novel manufacturing methods requires knowledge not only on these methods themselves but also on advanced design approaches and e.g., materials. We aim at tackling the whole chain from the design to powder proce...
This study introduces the properties of soft magnetic Fe-49Co-2V material produced by Laser Powder Bed Fusion (LPBF) process from gas-atomized powder that are compared to printed binary Fe-Co alloys.
For reduction of vibrations and noise of electrical machines, the computation of the magnetic force distributions and the ensuing deformations are needed. Here we utilize nodalforce method in open-source Finite Element software Elmer to compute the force distributions and the vibrations of an induction motor during start-up.
The multi-slice method allows approximation of the 3D phenomena without carrying out a full 3D analysis, e.g. in skewed radial flux electrical machines. The idea is to divide a 3D machine into several 2D FEM models along the axis, connected by electrical circuits. Here we show how the multi-slice method is perfect for parallel computation; the comp...
Multi-slice methods allow us to approximate the 3D phenomena without carrying out a full 3D analysis, e.g. in skewed radial flux electrical machines. The idea is to divide a 3D machine into several 2D FEM models, only connected by electrical circuits. Here we show how the multi-slice method is perfect for parallel computation; the computation effic...
This paper describes multi-slice modelling and validation of an axially skewed synchronous machine in 2D domain. The technique involves coupling of circuit and electromagnetic domains together with carefully constructed geometry. The model size in comparison with full 3D simulation reduces considerably. Developed 2.5D multi-slice model allows fast...
This paper demonstrates a workflow for multi-physical simulation and design optimization of electrical machines using open-source tools. The workflow demonstrates applicability of open-source tools for all steps of complex 3D Finite Element Method modelling of an electrical machine — geometry production, meshing, pre-processing, solving (even in ma...
Digital design and virtual engineering are nowadays the means for efficient machine design and product development. However, the full potential of the simulation-based approach has not been exploited.
At the time of writing this SIMPRO project final report, Finland is going through a period of economic recession, and all the sectors are trying to...
In electrical machine R&D, like in other fields, different computation methods are needed for different purposes. For detailed analysis and product design, a multi-physical finite element (FEM) analysis is required. However, if advanced multi-objective optimisation of electromechanical devices is pursued, the computational burden of FEM analysis is...
Industrial processes require sufficient computational resources and their high availability,
along with right tools and practices. Often, the amount of computational resources is not the problem, but the easy and efficient utilisation of the resources. To tackle this challenge, a class of information systems, computational distributed resource mana...
After its recent improvements described here, open source finite element software Elmer is shown to be a highly efficient option for electrical machine modeling. The parallelization of computational burden is shown to be a necessity. The methods implemented enable applying fully parallel computation to electrical machine models, including rotation...
Precise modeling of the magnetic field in the coil wire of an electric machine often becomes a major challenge: with the high number of turns and small penetration depth, the number of degrees of freedom exceeds reasonable limits in any standard approximation method. Precise approximation, however, is critical, e.g., to reliable coil loss estimatio...
Open source finite element software Elmer is shown to be a highly efficient option for electrical machine modelling. The need for 3D electrical machine simulations is justified and the parallelization of computational burden is shown to be a necessity in the future. Computational experiments performed demonstrate that Elmer can effectively utilize...
Purpose
– The authors aim to search for a practical and accurate way to get good loss estimates for coil filaments in electrical machines, for example transformers. At the moment including loss estimations into standard finite element computations is prohibitively expensive for large coils.
Design/methodology/approach
– A low-dimensional function...
Torque density of radial, axial and transverse flux machine topologies is investigated. A 10-kW, 200-rpm motor is chosen as a test case. Radial and axial flux motors that fulfill the key specifications of the selected test case are designed employing in-house analytical dimensioning tools and MATLAB genetic multi-objective optimization. Rather simp...
This paper shows a general review of Switched Reluctance Motors (SRM), reports the conversion of Active Magnetic Bearing (AMB) to SRM and discusses methods to estimate the torque produced in SRM. AMB converted to SRM has been tested on a laboratory scale test rig and its torque production measured. The novelty of this paper is the modified analytic...
This paper studies the effect of the choices made during the design process of a permanent magnet synchronous machine. An analytical dimensioning tool is used for creating different designs and a multi-objective genetic algorithm for finding the most interesting designs. As a result, it was found that the amount of permanent magnet material and the...
The aim of this paper is to model solid coil filaments and estimate their current distributions in electrical machines while having a properly defined connection to the driving circuit. Prohibitive computational cost is lowered by separating the boundary value problem into two subsystems. The coupling is established with a well-defined flux linkage...
In this work, we developed a geometric computational method for electromagnetic wave problems. The method unifies the spatial and temporal discretizations and produces a four-dimensional spacetime computational scheme, which treats spatial and time dimensions equally.
This new method seeks primarily to develop the current geometric methods, i.e.,...
We examine the effect of the cell type on the accuracy of Yee-like schemes. The approach is built over an error bound introduced for the discrete counterparts of the constitutive laws. We specify which geometric properties of the cells have an effect on the approximation errors. The convergence properties of different cell types are demonstrated wi...
If constitutive laws can be expressed with diagonal matrices in
wave propagation problems, Yee-like scheme will be explicit. As
finite-element kinds of meshes provide flexibility in modeling complex
geometries, they are preferred to regular grids in some cases. However,
finding such diagonal matrices for an arbitrary finite-element mesh is
not triv...
Projects
Projects (8)
This research project aims at developing modern artificial intelligence-based methods for condition monitoring of electromechanical energy conversion systems. We will produce synthetic augmented data to be used to train the artificial intelligence (AI) algorithms, which will combine data from different application domains, allowing the transfer learning.
The results of the project are expected to produce new knowledge on how to optimally leverage AI algorithms for energy conversion systems.
