纵向磁场下中频真空电弧集聚行为及其控制机理研究

随着多电/全电飞机的发展，中频（360Hz～800Hz）发电技术将全面应用于航空供电系统。目前航空供电系统采用空气断路器控制保护，而频率越高电弧开断越困难，严重限制了供电系统向大容量方向发展。真空开关技术开断性能好，环境适应性强，具有应用于航空供电系统的优势，而中频真空电弧开断性能研究是其成功应用的关键问题。本课题以中频真空电弧为研究对象，从微观参数和宏观形态角度出发，实验分析真空电弧等离子体的电子温度和电子密度分布特性，观测纵向磁场中不同电流等级在不同频率下的真空电弧形态及快速演变过程，分析影响电弧集聚行为的因素，建立中频真空电弧等离子体的磁流体动力学模型，研究触头结构参数、触头开距、外加磁场与产生阳极斑点的电流阈值的关系，进而掌握中频真空电弧集聚行为的控制机理，提高真空开关开断能力，为研制适用于航空中频和工业中频电源系统的开断容量为20kA的小型化真空开关提供理论依据。

With the development of more-electric aircraft (MEA) and all-electric aircraft (AEA), intermediate-frequency (360Hz～800Hz) power supply system is becoming popular. Air circuit breaker is widely used for protecting aero generator. Arc interruption in air breaker is much more difficultly extinguished when frequency increases, which limits the aero power supply system having large-capacity and miniaturization. Vacuum switch has large capability and good adjustability, which reaches the priority in aviation field. It is one of the important issues to investigate the performance of interruption of intermediate-frequency vacuum arc in order to apply vacuum switch. Intermediate-frequency vacuum arc is the research object in this subject, according to the microscopic parameters and the macro-morphology. Microcosmic parameters of the vacuum arc plasma, such as temperature and density distributing of electron, are measured and analyzed. The vacuum arc shape of different current and frequency under axial-magnetic-field is observed. The factor of constricted behavior is analyzed. The MHD model of the vacuum arc plasma is established. The quantitative relationship between external magnetic field, contact structure parameter, contact open distance and the anode spot current threshold is got by experiment. The control strategy of vacuum constricted arc will be found. As a result, the capability of vacuum switch will be improved. It is significant to provide a theoretical basis for the development of the miniaturization vacuum switch which has the breaking capability of 20kA and is suitable for intermediate-frequency power supply system in aero and industrial application.