Research And Development Low Voltage High Current Convertor Coupled With Planar Transformer

With the progress of electronics and development of telecom and power industry, more and more high requirements for telecom switching power are put forward. Presently, most telecom power companies in China are still using Phase Shifted Full Bridge ZVS-PWM, traditional transformer and full-wave rectifier to design Low Voltage High Current convertor, but they have not been met the marketing requirements that is High Efficiency, High Density, Low Ridiation, Low Size.In this thesis, several topology circuits are analysed and compared, including traditional Full Bridge PWM convertor, Phase Shifted Full Bridge ZVS-PWM convertor, Phase Shifted Full Bridge ZVZCS-PWM convertor and Phase Shifted Full Bridge ZVS-PWM convertor with Double Current Rectifier, and their merits and demerits are also presented. And then we choose Phase Shifted Full Bridge ZVS-PWM convertor with Double Current Rectifier, come up with improving its design using planar transformer, analyse its winding structure, thermal model and leakage inductor, point out the actual problem we can solve, and provide the design procedure of planar transformer. Considering large loop current exists in Phase Shifted Full Bridge ZVS-PWM convertor, we adopt double current rectifier and using two parallel MOSFET, so that primary current can be decreased and MOSFET can be easy to choose, and also enhance the efficiency. What's more, we can reduce the output choke size. In this thesis, we will analyse and compare using the different core material to make the output choke, point out the feature of several core material application, and then choose the core which is best price and quality to make the output choke.In this chapter, we will make the practical 4275W power rectifier using in the application of outputting low voltage and high current. Finally, we will provide the experimental waveform and test result. It is significant for domestic power supply companies to research and design telecom power supply in the future.