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

• This paper presents an evaluation of differentmodulation techniques and different levels of switching frequencyrandomization for a rear axle electrical drive unit used in auto-motive applications. Inverter and machine losses, and perceivedsound quality of high-frequency acoustic noise are investigated byfinite element calculations, experimental testing, and subjectivenoise assessment. Additionally, stator current harmonics, airgapflux density harmonics, and force density harmonics are comparedfor space vector modulation (SVM) and discontinuous pulsewidthmodulation through finite element modeling. The main conclusionis that, primarily in the field weakening region, significant energysavings can be achieved (up to 17% decrease in total inverter losseswith a switching frequency of 10 kHz). This is obtained withoutdeterioration of perceived sound quality by the use of discontinu-ous pulsewidth modulation with switching frequency randomiza-tion. Furthermore, randomization of the switching frequency doesnot improve the perceived sound quality of the acoustic noise whenusing SVM. However, for discontinuous pulsewidth modulation,improvements in perceived sound quality when randomizing theswitching frequency are observed, primarily below base speed.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Teknisk akustik

Engineering Acoustics

Publikations- och innehållstyp

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