A novel pre-stabilizing circuit of EPC for space TWTA using quasi-resonant flyback converter

The function of the pre-stabilization circuit in the traveling wave tube power supply is to convert the unstable bus voltage on the satellite into a stable DC output. The pre-stabilizing circuit of the traveling wave tube generally adopts the Buck structure. However, there is a suspension driving problem in the Buck circuit, which will make the driving circuit become complicated. At the same time, the efficiency of Buck is generally 90%, and Buck circuit can only be used to reduce voltage. In order to solve these problems and improve circuit efficiency, this paper proposes a new type of pre-stabilization circuit based on quasi-resonant flyback converter. The circuit can realize buck or boost, and the main switch tube has no floating drive problem. In the case of 28V input and 35V output, the efficiency reaches 91%. Therefore, the quasi-resonant flyback converter can replace the Buck for the pre-stabilization circuit.