Application of Mn-Zn Ferrite to Passive Common-Noise Canceller Placed on Inverter DC Side

This paper considers an application of Mn-Zn ferrite to a passive common-noise canceller (PCC) placed on an inverter DC side (DC-PCC). Although volume and weight of a common-mode (CM) transformer in the DC-PCC increases compared with that using nanocrystalline material, a cost could be reduced. An attenuation performance of a CM voltage is experimentally verified by a voltage-source inverter with a prototyped DC-PCC using nanocrystalline material and Mn-Zn ferrite. Experimental results show that the attenuation performance of the CM voltage is almost the same over a wide range of from a switching frequency of 100 kHz to 10 MHz. This result indicates that even without reaching permeability of nanocrystalline material, good attenuation performance of the CM voltage can be achieved with magnetic materials having permeability such as typical Mn-Zn ferrite considered in this paper. This is because that a coupling coefficient of a compensating winding of the CM transformer seems to be the same for the CM transformers using nanocrystalline material and Mn-Zn ferrite over a wide frequency range.