定子电流环控制在异步电机矢量控制系统占有非常重要的地位,直接关系牵引系统的转矩控制快速性和系统稳定性。然而,在大功率牵引传动系统中,为了降低开关器件的损耗,往往牵引逆变器的开关频率只有几百赫兹,这使得电流环带宽受限;另一方面控制环路中存在较大的延时,加剧了交流感应电机dq轴电流的交叉耦合程度,进一步降低了电流环的性能,严重时甚至导致系统不稳定。为了克服这些问题,进一步提高牵引感应电机的动态性能,首先在复矢量概念基础上,建立精确的含有延时在内的逆变器供电的异步电机的离散数学模型,接着分析了延时对异步电机数字%Stator current controller plays an important role in vector control of induction motors,which affects the response and stability of traction control.But in high power ac drive system,the traction converter often operates at only a few hundred switching frequencies to reduce the dynamic losses of the power devices,which makes current loop bandwidth limited,also leads to large one-switching-cycle control delay,enhancing the ac induction motor dq axis current cross coupling,further reducing the transient performance of the current loop.In order to overcome these problems,and improve the dynamic performance of the traction induction motor,it＇s first discrete model of induction motor fed by pulse width modulation（PWM） inverter based on complex vector is established,and thereafter,the influence of delay is analyzed.Then,using the principle of zero-pole cancellation,and a discrete current controller based on complex vector is proposed,by a way to compensate one-switching-cycle control delay,which realizes zeros/poles cancellation.Experimental results show that the method using improved complex vector synchronous frame PI controller with delay compensation can improve dynamic performance and cancel cross coupling between the dq current components.
展开▼
