航空直流起动发电机换向火花抑制研究

Study on commutation spark suppression of aviation DC starter-generator

针对航空直流起动发电机大电流、高转速产生的换向火花导致换向器表面高温烧蚀换向片,同时换向火花产生的电磁辐射对飞行器的通讯系统造成干扰的问题,根据经典换向理论建立直流起发电机换向数学模型,从电磁优化和机械试验两个方面研究了换向火花的抑制措施。首先,从电磁角度研究主磁极计算极弧系数对电流换向的影响,当计算极弧系数为0.65时电机近似直线换向;当电刷覆盖系数为2.41时,较小电抗电动势降低了换向电流,同时对电机起动性能和发电性能影响忽略不计。然后,从机械结构角度对不同电刷材料和不同电刷压力开展试验,结果表明选取52 kPa的电刷压力和TDQ52有芯柱电刷,脉动电压从0.88 V降低到0.53 V,电机在起动和发电两种状态下的换向火花都显著减小。所采取措施对于提高电机航空电源品质和延长电机使用寿命具有重要价值。

Aiming at the commutation sparks generated by the high current and high speed of the aviation DC starter generator,which cause high-temperature erosion of the commutator blades on the commutator surface,and the electromagnetic radiation generated by the commutation sparks interferes with the communication system of the aircraft,based on the classical commutation theory,the mathematical model of DC starter generator commutation was established,and the suppression measures of commutation spark were studied from two aspects of electromagnetic optimization and mechanical test.Firstly,the influence of the calculated polar arc coefficient of the main pole on the current reversal was studied from the electromagnetic point of view.When the calculated polar arc coefficient is 0.65,the motor is approximately rectilinear reversal.When the brush coverage coefficient is 2.41,the smaller reactance electromotive force reduces the commutation current,and the effect on motor starting performance and generation performance is ignored.Then,different brush materials and different brush pressures were tested from the perspective of mechanical structure.The results show that when 52 kPa brush pressure and TDQ52 core brush are selected,the pulsating voltage is reduced from 0.88 V to 0.53 V,and the reversing spark of the motor is significantly reduced in both starting and generating states.It is of great value to improve the quality of aviation power supply and prolong the service life of motor.