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Dive into the research topics where David Lennström is active.

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Featured researches published by David Lennström.


ieee transactions on transportation electrification | 2016

Influence of Inverter Modulation Strategy on Electric Drive Efficiency and Perceived Sound Quality

Andreas Andersson; David Lennström; Arne Nykänen

This paper presents an evaluation of different modulation techniques and different levels of switching frequency randomization for a rear axle electrical drive unit used in automotive applications. Inverter and machine losses, and perceived sound quality of high-frequency acoustic noise are investigated by finite element calculations, experimental testing, and subjective noise assessment. Additionally, stator current harmonics, airgap flux density harmonics, and force density harmonics are compared for space vector modulation (SVM) and discontinuous pulsewidth modulation through finite element modeling. The main conclusion is that, primarily in the field weakening region, significant energy savings can be achieved (up to 17% decrease in total inverter losses with a switching frequency of 10 kHz). This is obtained without deterioration of perceived sound quality by the use of discontinuous pulsewidth modulation with switching frequency randomization. Furthermore, randomization of the switching frequency does not improve the perceived sound quality of the acoustic noise when using SVM. However, for discontinuous pulsewidth modulation, improvements in perceived sound quality when randomizing the switching frequency are observed, primarily below base speed.


SAE International Journal of Passenger Cars - Electronic and Electrical Systems | 2014

NVH Integration of Twin Charger Direct Injected Gasoline Engine

Ashish Shah; David Lennström; Per-Olof Sturesson; William Easterling

The increased focus and demands on the reduction of fuel consumption and CO2 requires the automotive industry todevelop and introduce new and more energy efficient powertrain concepts. The extensiv ...


SAE International Journal of Passenger Cars - Electronic and Electrical Systems | 2015

Car Ride Before Entering the Lab Increases Precision in Listening Tests

Arne Nykänen; David Lennström; Roger Johnsson

Subjects who are well aware of what to judge commonly yield more consistent results in laboratory listening tests. This awareness may be raised by explicit instructions and training. However, too e ...


SAE International Journal of Passenger Cars - Electronic and Electrical Systems | 2013

Determination of Radiated Sound Power from an Electric Rear Axle Drive In-Situ and its Contribution to Interior Noise

David Lennström; Roger Johnsson; Arne Nykänen

System and component target setting for noise and vibration are important activities within automotive product development. New challenges arise when electric motors are introduced into cars tradit ...


Applied Acoustics | 2016

Validation of the blocked force method for various boundary conditions for automotive source characterization

David Lennström; Magnus Olsson; Frédéric Wullens; Arne Nykänen


International Congress and Exposition on Noise Control Engineering : 15/09/2013 - 18/09/2013 | 2013

Prominence of tones in electric vehicle interior noise

David Lennström; Thomas Lindbom; Arne Nykänen


Aachen Acoustics Colloquium 2011 : 22/11/2011 - 23/11/2011 | 2011

Sound Quality Evaluation of Electric Cars - Preferences and Influence of the Test Environment

David Lennström; Arne Nykänen


Archive | 2015

METHOD AND SYSTEM FOR MASKING NOISE

David Lennström


SAE International Journal of Passenger Cars - Electronic and Electrical Systems | 2014

The Influence of the Acoustic Transfer Functions on the Estimated Interior Noise from an Electric Rear Axle Drive

David Lennström; Roger Johnsson; Arne Nykänen


SAE Technical Paper Series | 2018

In-Situ Characterization of Vibrations from a Door Mounted Loudspeaker

David Lennström

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Arne Nykänen

Luleå University of Technology

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Roger Johnsson

Luleå University of Technology

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