Research On Fault Simulation And Diagnosis Method Of Stator Inter-turn Fault Of The Asynchronous Motor

Asynchronous motors are widely used in various fields because of their superior performance,and the probability of stator inter-turn fault will be high if they run for a long time.Operating experience shows that once a slight stator inter-turn fault occurs,if it not identified in time,inter-tum fault tend to evolve into grounding fault or phase-to-phase fault in a very short period of time,with serious consequences.So,asynchronous motor needs a reliable and efficient fault diagnosis method.Therefore,asynchronous motor require reliable and efficient method of fault diagnosis.Before putting the fault diagnosis method into the project,it is necessary to verify the correctness and practicability of the diagnosis method.At this time,it is important to verify the selection of the fault simulation method.Hence,it is of great engineering significance to study the fault simulation and diagnosis method of the stator winding of the asynchronous motor.In view of the fact that negative sequence current is easy to be affected by harmonic,noise and other factors during extraction,the complexity of spectrum analysis makes fault diagnosis difficult to give consideration to reliability and high efficiency,and the intelligent diagnosis method lacks practicality in engineering,a new feature quantity Ipgz is proposed to diagnose stator inter-turn fault.Firstly,from the perspective of motor construction and operation mechanism,the selection methods of branch circuit and circuit before and after the fault of asynchronous motor are analyzed based on the multi-loop theory,and its modeling is carried out.Secondly,the increased current frequency in stator after fault is analyzed according to the motor magnetic field after fault.Then the expression of fault characteristic quantity Ipgz,which can reflect the current magnitude of these frequencies in non-ideal condition,is derived by using multiple parker transform and filter processing.Finally,according to the established multi-loop mathematical model,the inter-turn fault of stator with different severity under ideal and non-ideal conditions is simulated.The analysis of results show that the Ipgz is positively correlated with the severity of the fault and has robustness to non-ideal conditions such as voltage source imbalance,and it is highly sensitive and reliable to diagnose the stator inter-turn fault of asynchronous motor by Ipgz.In view of the fact that the pure physical simulation platform is expensive and unsafe,pure virtual simulation platform is very different from actual engineering,and the existing semi-physical simulation platform is not targeted for motor fault diagnosis and expensive,a low-cost semi-physical real-time simulation simulation platform for motor fault diagnosis is built.Firstly,the framework of the semi-physical real-time simulation platform is designed based on the concept of hardware-in-the-loop.Then according to the requirements of the motor fault diagnosis platform,the hardware selection,software development and communication design of the platform were completed.Finally,the diagnosis method proposed in this paper is verified by the established simulation platform.The results show that the semi-physical real-time simulation platform can achieve 1:1 real-time simulation under the condition of low cost,and it is feasible to verify the diagnostic method.