Effective random space vector modulation for EMI reduction in low-cost PWM inverters

Experimental investigation of electromagnetic interference (EMI) effects in an induction motor drive with a PWM voltage-source inverter is described. A novel, simple version of random pulse width modulation (RPWM) based on the space-vector PWM technique is employed. The switching frequency of the inverter is varied randomly from one switching interval to another, but in contrast to the existing RPWM techniques, only two values of the switching frequency are used. This simplifies the control algorithm and selection of settings of current controller spectra of EMI conducted to mains and of the output voltage are presented and compared with the deterministic and multiple-frequency cases