Xiaofeng Wu

Design, Modeling, and Improvement of Integrated EMI Filter With Flexible Multilayer Foils

Integrated electromagnetic interference (EMI) filter design method with flexible multilayer (FML) foils is presented. An analysis model for integrated EMI filter with FML foils, distributed electromagnetic component (DEMC) model, is proposed. The DEMC model is verified by the experiment. In addition, method to improve the high-frequency performance of integrated EMI filter is investigated. Prototype of integrated EMI filter with FML foils is made for 1 kW switching power supply. In comparison with the traditional discrete EMI filter, it can reduce total volume by 45%.

High power high frequency zero current transition full bridge DC/DC converter

A novel zero current transition (ZCT) full bridge PWM DC/DC power converter is proposed. Based on the ZCT technique, this circuit realizes the ZCS of the active switches and the auxiliary switches. In the full range of loads, it can be operated in the constant frequency soft-switching mode. On the basis of the illustration of its operation principle, a detailed design approach is included in this paper. Simulation results and the experimental results of a 5 kW 50 kHz DC/DC power converter are also presented.

Integrated EMI filter design with flexible PCB structure

A novel integrated EMI filter structure is proposed in this paper, based on the flexible PCB integrated L-C winding. By employing this integrated L-C structure, CM inductors, DM inductors and CM capacitors are integrated in a single unit. By compare with the planar PCB winding that used in previously proposed method for integrated EMI filters, we found that flexible PCB winding need less length, which means less loss and room. A prototype was built, and measurement result presented.

Integration of Both EMI Filter and Boost Inductor for 1-kW PFC Converter

In order to increase the power density of the power factor correction converter, a novel integrated structure for both the electromagnetic interference (EMI) filter and the boost inductor is proposed with the flexible multilayer foil integration technique, which can reduce the volume of these passive components. Also, the performance of the proposed integrated structure is investigated based on the distributed electromagnetic component model. Furthermore, the design procedure for the integrated structure is detailed. Finally, a prototype of the integrated structure for both the EMI filter and the boost inductor has been built and the experiments demonstrate the validity of the integrated structure.

An integrating structure of EMI filter based on interleaved flexible multi-layer (FML) foils

A novel integrated EMI filter structure is proposed in this paper, based on FML foils. It integrates common mode inductors and differential mode capacitors and inductors into a single unit. A novel interleaved flexible multi-layer (FML) foil structure is proposed to overcome the difficulty of enlarging the DM capacitance. A prototype is constructed based on this concept and was put into a front-end converter to replace a discrete EMI filter. Testing result presented.

Design and experiment research of integrated EMI filter based on flexible multi-layer foils

A novel passive integration structure based on flexible multi-layer foils was proposed for EMI filter in switching-mode power supply. Common mode (CM) inductors and capacitors, differential mode (DM) inductors and capacitors were all integrated in a single unit. This passive integration applied flexible multi-layer foils (FML). Prototypes were implemented for an 1kW switching power supply. The conductive EMI testing result was presented. The temperature rising and efficiency curves of the integrated EMI filter were also presented. In comparison with the discrete EMI filter, the prototype in this paper can reduce the volume by 32%.

Modeling of integrated EMI filter with flexible multi-layer (FML) foils

A model of Distributed Electromagnetic Component (DEMC) for integrated EMI filter based on FML foil is proposed in this paper. The model is used for estimating the insertion loss of integrated EMI filter with FML foils. In this model, distributed parameters such as parasitic capacitance, magnetic coupling between conductors, core loss, copper loss, dielectric loss of the magnetic core are all included. Prototype was built. The model is verified by the experiment.