Study on common mode EMI suppression method in NC machine tools

Conducted electromagnetic interference in numerical control machine are introduced at first. PWM motor drive system is widely applied to numerical control machine tools. However, owing to power converter adopts pulse width modulation, which inevitably causes conducted common mode EMI. Common mode EMI generated by voltage source PWM inverter and the essences of its adverse effects are investigated in the paper, and common mode EMI reducing methods are also presented. Finally, the common mode EMI suppressing methods are expounded.