方波工况下基于q轴电流误差的异步电机转子磁场定向误差校正策略

A Correction Strategy of Rotor Flux Orientation Based on q-axis Current Errors for Induction Machines Operated Under Square Waves

在异步电机的控制中,转子磁场定向控制以其高转矩控制精度和快速的动态响应速度得到非常广泛的应用,但是在交流电力机车等大功率应用领域,电机在弱磁区通常采用方波控制,电机电压失去调节能力,造成传统的矢量控制算法失效。该文对异步电机方波控制策略进行了研究,提出一种方波工况下异步电机转子磁场定向角度误差的实时校正策略,该方案中采用电流开环控制,通过分析磁链角度误差对电机d、q轴电压指令值与实际值的影响,进而利用电机模型提出通过q轴电流参考值和反馈值的误差消除方波工况下转子磁场定向角度误差。仿真和实验都验证该方案能够对各种原因引起的转子磁场定向角度的误差起到很好的校正效果,使电机转矩输出在方波下仍然具有高稳态精度和快速的动态响应速度。

The vector control has been widely used in the induction machine control for the accuracy and the fast dynamic response of torque control,but in the high power occasions such as AC locomotives,induction machines usually operate under square waves in the field weakening area,which makes traditional vector control can not be used because of the constant output voltage.In this paper,a field orientation correction strategy under square waves was proposed in which the current uses an open loop control method.Through analyzing the effect of inaccurate field orientation to d-axis and q-axis voltage and using an induction model,the field orientation correction could be achieved by using q-axis current errors between the command and feedback values under square waves.Simulation and experiment results prove that even in the square wave condition,it can also get high torque control accuracy and a quick dynamic response.