Integrated EMI Filter With Flexible Multi-layer Foils

An Electro Magnetic Interference (EMI) filter is always needed in power electronics device. The traditional EMI filter is composed by discrete passive components, which occupied a large room. The electro magnetic integration technic is an alterlative way of reducing the volume of passives and improving the power density.The target of this dissertation is to integrate the inductors and capacitors of EMI filter together with Flexible Multi-Layer (FML) foil structures, to research tools for analyzing and designing, to reduce the volume of EMI filter. In the second chapter of this thesis, the electrical performance of passive integration technology that based on FML foil with variation of connecting sturctures is analyzed and the comparison between the integration methods by planar PCB and FML foils is present. In the third chapter of this thesis, some structures that integrate part or all of passive components of EMI filter with FML foils are proposed. In the fourth chapter of this thesis, a model of Distributed Electro-Magnetic Components is proposed based on the analyzing of inner electro-magnetic relationships between inductance and capacitance units. In the fifth chapter of this thesis, prototypes of integrated EMI filter were built for a 1kW front-end converter product. Experement results were presented. The volume, efficiecy and EMI filtering ability of integrated EMI filter prototypes were compared with those of discrete EMI filter. In the sixth chapter of this thesis, a method of improving the high frequency property of integrated EMI filter by integrated damping resistance which realized by selected materials for magnetic core, dielectric and conductive layers was proposed. Calculated and experimental results verificated the effectiveness of this method.Comparing to the discrete EMI filter for 1kW front-end converter, the prototype in this thesis can save 45% volume, and is of better filtering ability with good temperature rising and efficency. Besides, the integrated EMI filter based on FML foils is convenient to be produced by industrial procedure.