Reduction of the Electromagnetic Interference Conducted to Mains in Inverter-Fed AC Drives Using Random Pulse Width Modulation

Results of an experimental investigation of the impact of random pulse width modulation (RPWM) on the electromagnetic interference generated in inverter-fed drive systems are presented. A novel voltage space-vector RPWM technique with a limited pool of switching frequencies was employed. Experiments with an induction motor supplied from a voltage-source inverter, performed in a certified shielded chamber, were focused on the electromagnetic noise conducted to mains. In comparison with the deterministic modulation case, significant reduction of the noise, especially with regard to the quasi-peak values, is shown, demonstrating an important advantage of random modulation.