Research On Key Aspectis In Standardization For Low Power Level DC/DC Converter

As an important development trend in power electronics, Power Electronics System Integration (PESI) has received more and more attention in the recent years. In this dissertation, the state of the art of power electronics is reviewed firstly, and then topology selection and optimization for low power level standardized DC/DC modules in PESI have been researched and discussed. This dissertation mainly focuses on four classes topologies selection including selection of non-isolated low power level standardized DC/DC topologies, selection of isolated low power level standardized DC/DC topologies, selection of multi-outputs low power level standardized DC/DC topologies as well as selection of synchronous rectification topologies in low power level D/DC modules.The key issues in non-isolated low power level DC/DC converters are transient response and efficiency. In this dissertation, some optimized topologies are proposed to improve the transient response, and the concepts of sired-equivalent-voltage-source method and varied inductor method are proposed to extent the duty cycle of buck converter and to improve the efficiency as well. Several topologies based on these two concepts have been compared and the relatively optimally-selected topologies are found. The research on the paralleled multi-module system has also been processed and a unified small signal model for different types of control methods has been proposed. The effects of current-sharing loop on single module output resistance and system stability has been analyzed.As well as the low power level isolated DC/DC converters are concerns, the relevant topologies have been thoroughly classified, synthesized and compared, and some new topologies have been proposed. Six isolated topologies are optimally-selected as the candidate topologies for the standardized DC/DC modules.Detailed review, classification and comparison of topologies for multi-output applications have also been presented, and some new topologies have been proposed. Several topologies are optimally-selected as the candidate topologies for the standardized multi-output DC/DC modules.Synchronous rectifier driving topologies for low power lever DC/DC converters have also been studied in this dissertation. A method to build ideal voltage-type synchronous has been presented and six ideal synchronous rectifier topologies are proposed as examples. Some improved symmetrical structure voltage-type and current-type synchronous driving topologies has been developed. Finally, different synchronous rectifier driving topologies suitable for three different types candidate standardized topologies, including asymmetrical structure, symmetrical structure and current-type, have been compared. And the most optimally-selected topologies have been achieved.