A method to control EMI noises generated by micro-surges appearing at terminals of electric machines connected to power converters via electric power wirings

This paper proposes a new method to control EMI noises including radiations, which are generated due to micro-surges occurring at machine terminals. The proposed control is performed using multi-layer printed power circuit techniques that prevent shaft currents from being transmitted to load sides. The points of the proposed control method are as follows, (i) sites where surge voltages are generated are moved to the terminals connected on the inverter (or converter) side from the motor (or AC reactor) terminals, (ii) EMI noises with high frequencies are bypassed via distributed capacitors formed by the dielectric layout between the first and second layers and bypassed noise currents are attenuated by damping resistors, (iii) Near magnetic fields are offset by the noises currents flowing mutually in the first and second layers in counter directions. The control method was verified through simulations and experiments and various EMI noises produced by micro-surges occurring at machine terminals could be effectively controlled.