基于蒙特卡罗法的感应电机转子槽数及转速辨识方法

Identification Method of Rotor Slot Number and Speed of Induction Motor Based on Monte Carlo Method

在实际工程中对笼型感应电机进行能效评估时,通常采用非侵入式的转子槽频率方法辨识电机转速,但前提是转子槽数需提前给定,从成本与不影响生产的角度考虑,如何快速便捷地辨识得出转子槽数成为关键。研究了一种基于可测电气量的电机转子槽数及转速辨识方法。通过电机的空载和负载两种特殊运行状态采集输入端电流数据,并通过傅里叶分解与蒙特卡罗(Monte Carlo)法推算出电机槽数;采集不同工况下的定子电流波形,进行快速傅里叶分解,估算负载转差率得出转子槽频率的大致区间,解决了转子槽频率和齿谐波容易混淆的问题;利用转子槽频率反推求解得到转子转速。以一台5.5 kW样机为例,对该转速辨识方法进行了实验验证,结果表明能够满足工程需求,该研究成果为电机转速辨识与能效准确评估提供了必要参考。

When evaluating the energy efficiency of cage induction motors in engineering practice,the non-invasive rotor slot frequency method was usually used to identify the motor speed.The premise of this method was that the number of rotor slots needs to be given in advance.Considering the cost and no impact on production,how to identify the number of rotor slots quickly and conveniently becomes the key problem.A method was researched for identifying the number of slots and rotational speed of motor rotor based on measurable electric parameters.The input current data were collected by the motor's no-load and load special operation states,and the slot number of the motor was calculated by Fourier decomposition and Monte Carlo method.The stator current collected under different working conditions was decomposed by fast Fourier decomposition,and the load slip rate was estimated.The frequency range of the sub-slot solves the problem that the rotor slot frequency and tooth harmonics were easily confused.The rotor speed was obtained by using the rotor slot frequency inverse calculation.Taking a 5.5 kW prototype as an example,the proposed speed identification method was verified by experiments.The results show that it could meet the engineering requirements.The research results provided necessary reference for the speed identification and accurate energy efficiency evaluation of motors.