5kW离子电推进大功率屏栅电源的设计研究

Design and Research of High Power Beam Power Supply for 5kW Ion Electric Propulsion

关键词:  离子电推进  电源处理单元  高电压  大功率  移相全桥  屏栅电源

Key words:  Ion electric propulsion  Power processing unit  High voltage  High power  Phase-shifted full bridge  Beam power supply

摘要:

针对航天器用5kW离子电推力器核心供电模块屏栅电源的技术需求，采用移相全桥技术设计了低电压输入高电压输出的大功率屏栅电源模块。对比分析了零电压开关ZVS和零电压零电流开关ZVZCS两种移相全桥方案后，得出ZVZCS更适合于电推进屏栅电源的设计。提出了ZVZCS移相全桥变换器CDD无损缓冲电路中辅助电容的设计方法，论述了屏栅电源功率级和控制电路的设计过程。通过实物产品验证表明：采用ZVZCS移相全桥技术设计的屏栅电源模块能在较宽的负载范围内实现超前桥臂和滞后桥臂的软开关，提高了变换器的效率；采用CDD无损缓冲电路能辅助实现滞后桥臂的零电流关断，降低原边电流的损耗，同时降低高压整流管的电压应力。在具备完善的输入滤波、浪涌抑制及母线开关等功能以后，最大功率下效率>95%。

Abstract:

Aiming at the technical requirements of the 5kW ion electric thruster beam power supply， a high-power beam power supply module with low voltage input and high voltage output is designed using phase-shifted full-bridge technology. Compared with ZVS（Zero voltage switching） and ZVZCS（Zero voltage switch and zero current switching）， ZVZCS is more suitable for the design of electric propulsion grid power supply， and the design method of auxiliary capacitors in the CDD（Capacitive diode diode） buffer circuit of ZVZCS phase-shifted full-bridge converter is proposed. The design process of beam power stage and control circuit is discussed. The engineering product verification shows that the beam power module designed with ZVZCS phase-shifted full-bridge technology can realize the soft switching of the leading bridge arm and the lagging bridge arm in a wider load range， which improves the efficiency of the converter. Using a CDD buffer circuit can assist in realizing the zero-current shutdown of the lagging bridge arm， reducing the conduction loss of the primary current， and at the same time reducing the voltage stress of the high-voltage rectifier. With complete input filtering， surge suppression and bus switch functions， the efficiency at maximum power is above 95%.