Research And Realization Of The Core Converter For TWT Power Supply With High Efficiency And High Power Density

As the centralized power supply and control system of the mini microwave transmitter, the technical level of Traveling Wave Tube (TWT) power supply with high efficiency, high power density restricts and impacts on the development of the transmitter directly.The thesis is primarily focuses on the integrated power supply system for miniaturization Travelling Waves Tube(TWT), which is used in the condition of low input voltage. On the basis of analyzing its characteristics and technical difficulties, a new switching power supply converter called Active Clamping Push-pull dual-voltage Converter(ACPDC) is proposed. This converter has two important advantages, the first one is that it realized the soft-commutation by utilizing the fringe resonance between its own parasitic parameters, which is very useful for reducing the volume and weight of the power supply. Secondly, the own boost multiple of the converter is high, and together with the utilization of multiple symmetrical dual voltage commutate technology in the output port solves the problems of the transform such as large boost multiples, big volume and difficult to execution, which is common in tradition high-voltage power supply. So ACPDC is more suitable for mini high-voltage DC/DC switch power supply with low input voltage.Firstly, the paper analyses the two different working modalities modes of the ACPDC, and discusses the principle of the converter under each mode in detail. And mainly talks about the soft-commutation condition of the switch tubes, gain characteristic and load characteristic of the converter, when working under the main working mode (boost mode). Then the design method of the converter's major parameters is presented, and the optimum design and improved method of the parameters which based on efficiency is also given. Secondly, the dynamic modeling approach of the converter is researched as well, and a new approach which called step-response fitting algorithm is proposed. Then the control strategy and the closed-loop emendation for this converter was discussed on this small signal model. Finally, the control circuit is designed for the converter by using CPLD and the existing power supply control chip, and a hardware experiment of the main circuit for the power supply of the TWT is done, the converter realized firm and high-efficiency(92.3%) output of 2000V/100mA. And the results of the experiment verifies that the given conclusion and methods of the proposed converter are correct.