Extraction And Analysis Of Electromagnetic Parameters Of Module In A New Type Of Integrated EMI Filter

The passive EMI filter is one of the most effective means for suppression of conductioninterference. However, the conventional filter consists of discrete inductors and capacitors, andaccounts for a very large volume in the whole power converter because of the discrete componentscome in different shapes and sizes and lower utilization space. Meanwhile, the high-frequencyperformance of EMI filter suffers from the parasitic parameters of discrete components. In order toreduce dimensional size of EMI filter and improve its performance, it is important to carry outresearch on planar integrated EMI filter for theoretical and engineering significance.The integrated LC structure, achieving the integration of inductance and capacitance, is the basicunit constituting the planar integrated EMI filter. The fundamental principle of electromagneticintegration is analyzed firstly in this paper, and the basic integration structure is confirmed through theanalysis of electric field and magnetic field distribution in different integration structure. Rectangularintegrated LC structure is optimized due to its defects. The achievement and design of planarintegrated EMI filter based on circular integrated LC structure is focus on this paper.The electromagnetic parameters of integrated LC structure is extracted using finite elementmethod (FEM) and analytical expressions. Based on analysis of the data, the variation of capacitance,inductance, resistance with frequency have been found. On this basis, detailed design procedure ofplanar integrated EMI filter based on circular integrated LC structure is discussed, and theapproximate formulas used in lumped parameters are given to guide the filter design. Finally, a planarintegrated EMI filter has been design and measured.