Impact of PWM switching frequency on the radiated acoustic noise from a traction motor

• The radiated acoustic noise from a traction motor at low speeds is dominated by the noise of electromagnetic origin. For a motor operated from pulse width modulated (PWM) converters, the switching frequency of the converter will have a large impact on the noise. The total harmonic distortion of the motor phase currents and thus also the exciting forces, will decrease with increasing switching frequency. Furthermore, changing the switching frequency will shift the frequencies of the exciting forces, hence have an influence on the coincidence with structural resonances of the motor. Tests have been performed on a traction motor and a decrease in sound pressure level with increasing switching frequency has been quantified and analyzed.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Farkostteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Vehicle Engineering (hsv//eng)

Keyword

Acoustic noise

Pulse width modulation (PWM)

Switching frequency

Traction motor

Electric machinery

Pulse width modulation

Switching

Voltage control

Exciting forces

Low speed

Motor phase

Pulse width modulated converters

Sound pressure level

Structural resonance

Total harmonic distortion (THD)

Traction motors

Publication and Content Type

ref (subject category)

kon (subject category)