Research On Loss And Torque Of Induction Motor Considering Inter-bar Current In Two-dimensional Field

The performance of induction motor(IM)has a great significance to the development of industry as the main electrical equipment for industrial production.In general,the size of induction motor is small or medium,the skewed rotor structure can suppress parasitic torque,electromagnetic vibration and noise.Meanwhile,the skewed rotor structure also increases the inter-bar current between the rotor bars and affects the starting performance and efficiency of the IM.Therefore,the study of the inter-bar current in the skewed induction motor is of great significance for analyzing the performance of the induction motor and improving the efficiency of the motor.This paper mainly studies the influence of inter-bar current on the performance of single-skewed induction motors.The transverse resistance value of the induction motor rotor is measured by the complete squirrel cage method.Aiming at the problem of small transverse resistance value,this paper compares the results of two measuring instruments to reduce the measurement error.At the same time,the virtual circuit of the rotor is built based on the measurement results,and different types of resistance changes can analyze the sensitivity of the measurement results.Aiming at the rotor structure of the 1.1kW squirrel-cage induction motor,the transverse resistance loop is considered to establish the rotor equivalent circuit,and the unit axial length motor is regarded as an unit motor.Through the calculation of the end ring loss in the adjacent unit motors,the inter-bar current loss was solved.For the whole motor,the overall inter-bar loss value of the motor was obtained by integrating the inter-bar losses in the unit motors along the axial direction.After summarizing the distribution law of the inter-bar current on the rotor surface in the single-skewed induction motor,based on the unit motor concept in the rotor analytical equation,a two-dimensional finite element model that can account for the inter-bar current was proposed,and no-load harmonic analysis of the modified finite element model is performed.Using the unit motor concept in the rotor analytical equations,by coupling the two-dimensional electromagnetic field,the transition layer was established in the rotor,the inter-bar current was considered in the two-dimensional finite element simulation,and the multi-section finite element method was used to equivalent the skewed slot induction motor,and predict the influence of the inter-bar current in the induction motor on the performance of the motor through this model.The simulation results of the Y802-2 induction motor model were compared with the inter-bar loss value of the three-dimensional finite element to verify the feasibility and effectiveness of the model.At the same time,the model was used to analyze the influence of the transverse resistance value on the starting torque characteristics of the motor,and finally analyzed the influence of inter-bar current on the motor torque when the slot shape changes.This paper provides a reference for exploring the influence of inter-bar current on motor performance.