Optimized FRFT Algorithm Based On PSO And Its Application In Fault Detection Of Induction Motor With Frequency Conversion Power Supply

The cage induction motor has the characteristics of simple structure,long service life and low price,so it is widely used in the field of transmission.However,due to poor working conditions,motor failure is still prone to occur,which brings huge economic losses to production and life.Therefore,it is very important to detect the fault of the induction motor in time,make early prevention and ensure the stable and reliable operation of the induction motor.As a common motor failure,the broken bar failure accounts for about 10% of the total number of motor failures.AC frequency conversion speed regulation technology is more and more widely used in motor drive due to its advantages of high efficiency,energy saving and good reliability.However,there are few studies on the fault detection of the induction motor in the state of variable frequency speed regulation.The previous fault diagnosis method of the broken rotor of the motor rotor is not suitable for the induction motor with frequency conversion power supply.In view of the above situation,this paper studied the fault detection of the broken rotor bar of the asynchronous motor under the variable frequency speed regulation based on the Fractional Fourier Transform,the specific content is as follows:(1)The motor stator current signal with frequency conversion power supply is similar to the linear frequency modulation signal,and its spectrum can be analyzed by the Fractional Fourier Transform of optimal order.However,for the traditional optimal order search method,there is a contradiction between the accuracy and the amount of calculation.To solve this problem,an improved FRFT algorithm based on particle swarm optimization is proposed.The algorithm replaces the traditional fixed-step traversal search with particle swarm intelligent search to improve the calculation accuracy and search efficiency of frequency modulation.The simulation and experiment analysis verified the effectiveness and superiority of the proposed improved FRFT algorithm.(2)Aiming at the problem of induction motor broken bar fault detection with frequency conversion power supply,a fault detection method based on the improved FRFT and Relax is proposed.Through the improving the FRFT algorithm,a highprecision frequency modulation can be estimated,and the linear frequency-modulated stator current can be converted into a constant frequency signal;On this basis,the fundamental wave and broken bar fault features are extracted and strengthened by the Relax algorithm.Simulation and experimental analysis verified the feasibility and effectiveness of the proposed fault detection algorithm.(3)Based on Lab VIEW,an on-line detection system for rotor breakage of induction motors is designed.Using Hall voltage and current sensors,synchronous data acquisition card and computer to realize the stator current signal acquisition;Then through Lab VIEW and Matlab mixed programming,realize the stator current signal preprocessing,real-time display and real-time analysis of multiple fault algorithms and other functions.The feasibility of the scheme was verified through performance testing.