Current control for induction motor drives using random PWM

Current control in voltage-source inverters with random pulsewidth modulation (RPWM) is investigated. The random modulation is introduced to alleviate the undesirable acoustic, vibration, and EMI effects in inverter-fed AC drive systems. A novel RPWM digital technique with dithering of the switching frequency and compensation of the processing time is described. Design of the current control loop is discussed. Results of investigation of an experimental drive system are presented, proving the feasibility of the proposed solutions.