轨道交通异步牵引电机低开关频率下定子磁链轨迹跟踪控制研究

Stator Flux Tracking Control of Induction Traction Motor at Low Switching Frequency for Rail Transmit

功率器件的低开关频率导致轨道交通牵引系统在全速范围内不能实现圆形定子磁链轨迹控制。直接自控制(DSC)广泛应用于轨道交通牵引传动控制,其定子磁链轨迹为六边形或十八边形,但随着逆变器最大输出电压越来越接近电机额定电压,未能实现对转矩的有效控制,产生较大的电流冲击和转矩脉动,影响系统控制性能。为解决此问题,本文基于优化脉宽调制策略,以异步牵引电机为控制对象将定子磁链轨迹跟踪控制算法应用于高速区,与应用于中低速区的DSC控制算法进行无缝切换,实现全速范围内的平滑过渡。仿真及实验证明了所提算法的正确性和可行性。

With the low switching frequency of power devices,the circular trajectory control of stator flux in the rail transit traction system can not be achieved in the whole speed range.Direct self control,proposed by professor M.Depenbrock,has been widely used in traction control of rail transit.The trajectory of stator flux is hexagonal or eighteen-corner.But when the approach of the maximum output voltage of the inverter to the rated voltage of the motor fails to achieve effective control of the torque,greater current shock and torque ripple will be caused,thereby affecting the control performance of the system.In order to resolve this problem,stator flux tracking control was proposed in this paper to control the induction traction motor based on optimal PWM.The method was applied to high speed range while the DSC was used in low and medium speed range.The simulation and experiment results showed the correctness and feasibility of the proposed algorithm.