Reducing Acoustic Noise Radiated by Inverter-Fed Induction Motors Controlled by a New PWM Strategy

This paper presents a new application of a control strategy to reduce the acoustic noise caused by pulsewidth-modulation (PWM)-controlled induction machine drives. The proposed strategy is based on a frequency modulation of the triangular carrier through a sinusoidal signal. It is used to decrease the acoustic noise and to achieve a reduction in the total harmonic distortion. The main advantage of the proposed method is that only one control parameter is necessary to modify the electrical spectrum, and so, mechanical natural frequencies are avoided while the number of pulses per period remains unchanged. The results obtained in laboratory tests are presented and compared to other acoustic measurements using different PWM strategies.