Novel Integrated CM Inductor for Single-Phase Power Converters with Reduced EMI

Ground leakage current and electromagnetic interference 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 a separate CM filter and a differential mode LCL filter. In this paper, an integrated CM inductor (ICMI) is proposed in which the LCL filter boost inductor and the CM choke are combined into a single component. This results in a reduction in the number of magnetic components required to build the 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 5-kW 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 an added ground capacitor in the power circuit as a CM filter can reduce the electromagnetic interference noise level up to 30 dB.