Abstract：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.
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2011, Vol. 26 
