Novel modulation technique to reduce acoustic noise and switching loss

Abstract

This paper proposes a novel modulation technique that reduces both motor acoustic noise and switching loss. The conventional discontinuous PWM method can reduce the switching loss to a greater extent compared to the conventional three-phase modulation method; however, the acoustic noise of the motor increases. The proposed technique adjusts the zero-sequence voltage given to the voltage references in such a way that the discontinuous part of the conventional discontinuous PWM method is changed smoothly. The switching loss with the proposed technique can be reduced to 58% of that with the conventional three-phase modulation method. The experimental results show that the acoustic noise can be reduced to a greater extent with the proposed technique compared to that with the conventional discontinuous PWM method.