电力机车牵引电机在方波下的控制策略

Control Strategy of Locomotive Traction Motor Under Square Wave Condition

在大功率交流电力机车牵引传动系统中,牵引电机在进入弱磁区之后通常要进入方波工况。方波下电机电压失去调节能力,使传统的矢量控制算法失效。本文中提出了一种基于电流开环控制的改进型矢量控制策略,使牵引电机在方波下仍然能够进行矢量控制;同时采用了一种改进型的电压控制器,保证了电机在弱磁区全速度范围内的最大转矩输出。最后利用电流开环控制的特点,提出了一种基于q轴电流误差的磁场定向校正策略,保证了方波下磁场定向角度的准确。仿真和实验结果证明了整个控制策略的有效性。

In the traction driving system of high power AC electrical locomotive, the traction motor usually operates under square wave condition. The loss of regulation capacity to voltage makes the traditional vector control can not work anymore. In this paper, a modified vector control based on open loop current control is proposed. Besides, a modified voltage controller is used in order to make the motor achieve maximum torque control during the whole speed range. In the end, a slip frequency correction strategy based on q-axis current error is proposed which can guarantee proper field orientation under square wave. Simulation and experimental results verify the validity of all the control strategy.