Common-mode noise reduction with two symmetrical three-phase inverters

In recent times, more than 60 percent of the world´s energy is used to drive electric motors. Because of the growing requirements of speed control, pulse width modulated (PWM) inverters are widely used in adjustable speed drives. Noise generated by PWM inverter fed AC motor drive systems causes severe parasitic current problems, especially at the cases of high frequency. This paper proposes two new methods to reduce common mode noise current generated by Inverter fed AC motor systems. The effect of two proposed methods have been verified by simulation and experiment. The results of simulation are very perfect because the common-mode voltage and the common-mode current are almost be reduced to 0V and 0A.