实用交流感应电机参数检测方法研究

Research on Practical Method to Identify the Parameters of AC Induction Motor

交流调速系统以其优越的性能,在生产实践中迅速推广使用,而检测到的电机参数是否精确,对于系统性能有着至关重要的影响。经过很多人的研究,一般认为:离线检测实现起来容易,但是检测的数据可用性不强;在线检测得到数据比较可靠,但是检测算法复杂,而且精度受到很多因素的影响,在实际中难以得到大面积应用。本文提出一种实用的电机参数检测方法,即离线定初值,在线跟踪调整的方法。离线测定通过变频器自有的资源实现,由变频器提供两种固定频率试验电压,测定电机在转速接近为零时的电流变化情况,即能得到电机的参数初值。根据电机参数的特点,即电感量几乎不变,电阻随电机运转时间加长缓慢变化的基本事实,只对当前电阻值进行检测。由于该方法理解容易、算法简单,在实际中推广的可行性更强。实验证明,该方法能实时精确推算出当前电机参数。

AC drive systems are employed in many situations for their high performance. However, the accuracy of the identified motor parameters affects the performance greatly. Much research on this area has done and it＇ s commonly considered that the results of the motor parameters by aft-line methods are easy to realize, but hard to utilize. The results derived by on-line methods are reliable but the algorithms of identification are complicated and affected by many other items. So either one cannot be widely applied. This paper proposed a practical method to identify the parameters which use the results by offline methods as initial parameters, trace and tune them by online methods. Inverter has the resource to realize offline identification by supplying two different frequency voltages and test the currents of the stator windings when the rotor is zero or nearly zero rpm speed. As we know the fact that when the motor running, the inductance parameters nearly keep constant, however the resistance parameters will rise slowly. Proper increment to initial resistance parameters to substitute the real resistance parameters will gain the same response. As this method is easy to understand and simple on algorithm, it could be more feasible to spread in many fields. Experiments testified this method can identified the parameters accurately in real time.