The Research On DC/DC Converter Of High Power Density

With the rapid development of power electronic and computer technology, the use ofswitching power supply and electric operational power supply based on the core of DC/DCconverter is becoming more and more widely. High efficiency, high power density isimportant requirements for aerospace power converter. With the development of relatedtechnologies, it has now become the common requirements of various industries.Improving the working frequency of switch converter, can greatly reduce switch converter volume, improve the power density. However improving switch frequency, theswitching loss, the electromagnetic noise and the switch device voltage or current stress are increased. In order to solve the the problem, soft switch technology is put for-ward. Soft switch technology can realize switch tube of zero voltage and zero currentswitching, improve efficiency, reduce electromagnetic interference.DC/DC converter can be divided into non-isolated DC/DC converters and isolatedDC/DC converters. A summary was given on the development and status of DC/DC converterwith soft-switching technology based on reading a lot of literature. The passive lossless Buckconverter with minimal stress used as the representative circuit of isolated DC/DC converterwas studied. The principle of its passive lossless was analyzed. A detail description was givenon the different working modes, and a detail analysis was carried out on the converter’s design.The simulation model was built and relative experiments were carried out. The results showthat the minimum stress passive lossless Buck converter can achieve zero-current andzero-voltage switching. The phase-shifted full-bridge of ZVZCS converter was used as therepresentatives of isolated DC/DC converter in research. A detail analysis was conducted onsoft switching principle, working mode, and relevant parameters. The simulation mode wasbuilt and relevant research was carried out. The voltage and current double closed-loopcontrol mode was set up. While verifying ZVZCS switching, the dynamic characteristics wereverified by sudden increase or reduce in load at the same time.Finally, a1kW experimental prototype was built and experiments were carried out. Theresults show that the switching devices can achieve ZVZCS switching by using soft-switchingtechnology. The working environment was improved; it can reduce the switching losses andincrease the working efficiency effectively.