Abstract
This research paper presents the acoustic noise produced by a three phase motor when driven by an inverter. The inverter is operated by various traditional approximated PWM switching schemes. Experiments show that the acoustic noise from the three phase motor changes with the variation of the PWM switching scheme. The PWM switching schemes included approximated sinusoidal, approximated third harmonic injected sinusoidal, approximated trapezoidal, and approximated triangular PWM switching schemes. The approximated trapezoidal PWM switching scheme yields the least acoustic noise. This paper highlights a relationship (in graphical terms) between the current in the neutral wire and the acoustic noise observed from the motor for various switching schemes. However, the relationship between the acoustic noise and switching scheme may require further research. Furthermore, results also show that the approximated trapezoidal PWM switching scheme yields the minimum current in the neutral wire.
