Low switching PWM strategy to reduce acoustic noise radiated by inverter-fed induction motors

This paper presents a control strategy based application to reduce the acoustic noise caused by a PWM-Controlled Induction Machine Drives. It is a controlled technique and it uses a trapezoidal modulator wave with a variable frequency sinusoidal carrier signal. The technique generates high quality voltages with very few commutations per cycle and is highly efficient in reducing commutation loss and acoustic noise radiated. The main advantage of the proposed method is that only two control parameters are necessary to get controllability, and so, the mechanical natural frequencies are avoided. One of them modifies the amplitude of the modulated output of the inverter and the other controls the frequency spectrum distribution. Results are checked experimentally and compared to other PWM techniques.