Space vector based random pwm algorithms for acoustic noise and harmonics reduction for voltage source inverter fed ac drive

Abstract

Conventional Space vector based Pulse Width Modulation (PWM) method is superior to Sinusoidal PWM technique in terms of its better DC bus utilization as well as harmonic reduction. But it doesn’t give solution to reduce acoustic noise which is more annoyance to the driver and the passenger or the human beings in certain applications such as electric propulsion or accessory drives. This paper presents space vector based random PWM techniques - a solution to reduce the acoustic noise as well spread spectrum resulting in low harmonic distortion as suppression of peak sound pressure levels. The techniques employed for a VSI fed Induction motor drive are 1) Random Zero vector PWM 2) Dual Zero Random PWM and 3) Variable Delay Random PWM. The spectrum plots of stator current demonstrate the effectiveness of the proposed PWM techniques. The feasibility of the proposed PWM techniques has been confirmed in terms of acoustical noise and harmonic distortion is presented in this paper.