Research On The Application Of The Magnetics-Integration Techniques In Switching Power Supply

Recently, the Magnetics-Integration (MI) techniques have attracted more and more attentions, for the Integrated Magnetics (IM) can help to reduce the core loss, core size, or ripple current compared with the Discrete Magnetics (DM). The purpose of this dissertation is to generalize the MI rules and to improve the power converters by the application of the IM as well.Firstly, this dissertation introduces the concept of MI techniques, reviews the developing history of MI techniques, generalizes the method to analyze the magnetics and the IM applications in different occations, points out that the appropriate choice of the IM is critical in the IM applications.Secondly, the general process of the IM application is presented in the thesis. The simple methods to derive IM converters and the general equivalent electrical circuit of the magnetics are proposed, which simplisize some part of the work in the IM applications, and have been applied in the following research in this thesis.Thirdly, the research on the IM applications is performed in 4 types of different converters.MI technique is applied in Flyback-Forward converter with Active Clamp circuit (FFAC converter) to integrate the transformer with DC flux bias and the output inductor. Based on the detailed analysis and comparision of different IMs, the appropriate IM is chosen. Analysis and experimental results indicate that the IM-FFAC converter is super to DM-FFAC converter in core size and core loss reduction.MI technique is applied in Forward converter with Active Clamp circuit (FAC converter) to integrate the transformer and the output inductor whose winding-voltage are in proportion. A novel IM-FAC converter is proposed, which has advantages not only in the core loss and core size reduction, but also in the ouput ripple current reduction, compared with the DM-FAC converter and the previous IM-FAC converter.MI technique is applied in the improved Current-Doubler-Rectifier Zero-Voltage-Switching Full-Bridge converter (CDR ZVS FB converter) to integrate the two ouput inductors whose winding-voltage are not in phase. Considering the requirement of the CDR ZVS FB converter and the difference of the integrated-inductors, the decoupled reversed integrated-inductor is chosen, which is proved better in core size and core loss reduction by the research results.The effects of the coupled inductor in multi-output converters on output dynamics, output ripple current and cross regulation have been analyzed in detail. According to the analysis, the novel methods to regulate the output ripple current or ripple voltage in the multi-output converters is presented in this thesis. The analysis and the experimental resultsverify the effectiveness of the methods presented.Finally, the usage of the MI techniques, the commonly used methods hi the IM applications and the usual MI rules are generalized, which will help to the further research and application of the MI techniques.