Novel integrated CM inductor for single-phase power converters with reduced EMI

Ground leakage current and electromagnetic interference (EMI) noise are important challenges during design of grid-connected power converters. Use of common-mode (CM) choke helps to mitigate these issues. A common practice is to use separate CM filter and differential mode (DM) LCL filter. In this paper an integrated CM inductor (ICMI) is proposed. In the proposed ICMI, the LCL filter boost inductor and the CM choke are combined into a single component. This results in size and cost reduction of the overall power converter. Steps involving design of the ICMI are provided. The proposed ICMI is fabricated in the laboratory. Experimental test are carried out on a 5kW single-phase grid-connected power converter, to validate the effectiveness of the proposed ICMI. The results show that the use of proposed ICMI along with a capacitor CMg in the power circuit as common mode filter can reduce EMI noise level up to 30dB.