Stationary Plasma Thruster Anode Discharge Power Supply

With the continuous development of China’s space technology, the satellitepropulsion technology has bacome more sophisticated. As an advanced method ofpropulsion, the electric propulsion with high specific impulse, low thrust, light weight, hasbeen widely applied in the international arena, and thus become a technology in urgentneed of development. Stationary plasma thruster is one of the more mature electricthrusters, and has got attention of the aerospace industry. Power processing unit is a powerconversion unit, providing energy to the propelant. It is an important composition of thethruster. The anode discharge supply is the core design and nodus of the power processingunit.The special working conditions of the anode supply is presented in this paper, andthen designs the overall power system. It is constituted of2+1parallel redundant modulesthat allows a module fails and quit running. A phase-shifted full-bridge zero-voltagetopology is chosen for the power module, the control of the module is implemented usinga UCC3895controller with the voltage control loop and the peak current inner controlloop. In addition, the current limit protection and output overvoltage protection aredesigned. Parallel current-sharing is achieved by droop control. An auxiliary power supplyfor the modules is designed, which is a flyback converter with3isolated outputs, andconstitutes input over and under voltage protection. Circuit parameters and functioncontrol circuits are disigned. A small signal model of current-control phase-shiftedfull-bridge is established to optimize the design of the control circuit parameters.Three prototypes are developed. Experiment wave shapes and efficiency curve of thepower module are given in the paper. At rated input, the maximum efficiency is up to92.1%. Three modules in parallel operation and two of them in parallel operation aretested, the degree of uneven flow is less than5%.