Influence Of Rotor Eccentricity On Electromagnetic Parameter For Permanent Magnet Synchronous Motor

As one of the most crucial components of ships,electric propulsion system is the power source of the stable and efficient operation of ship equipment.In the modern electric propulsion system,the performance of the motor directly determines the output power performance of system.Rely on the small size,high power density,high efficiency and good speed control performance,permanent magnet synchronous motor is commonly used in ship driving equipment.In practice,because the working environment of motor is very complex,motor will inevitably encounter faults.Rotor eccentricity fault is one of the common faults of motor.In order to achieve the purpose of preventing and detecting faults,it is very meaningful to understand the performance of the motor under fault condition.In this paper,a permanent magnet synchronous motor is selected as the research object,its rated power is 50 k W.Based on the theory of motor and electromagnetic field theory,the finite element method is used to analyze the normal operation and the eccentric faulty operation of this motor.The model of motor is built under different eccentric state and different load condition.By calculated these models of motor,the performance of motor under the eccentric state could be understood.Firstly,the finite element model of normal working motor is built under no-load condition.The electromagnetic performance of the normal running motor at no-load condition is observed.Secondly,the models of the motor under different eccentric conditions are established by the same method.Through the calculation of each models,the electromagnetic performance such as motor magnetic field,the air gap magnetic density,electromagnetic force density on the outer surface of the rotor and the core loss of motors is obtained.Through the comparison and analysis of electromagnetic performance of every motor,the effect of eccentricity on the performance of the motor is obtained.Thirdy,the motor when the eccentricity ratio is 30% is modeled under no-load,0.5 times rated load,rated load and 1.1 times rated load conditions.The air gap magnetic density,electromagnetic force density on the outer surface of the rotor and the core loss of each motor are calculated respectively.By analysis of these parameters,the influence of load variation on the electromagnetic performance of the motor under eccentric fault could be obtained.In this paper,the effective conclusion is drawn through the accurate simulation.This conclusion provides strong support for exploring the performance of the motor with eccentric fault and lays a theoretical foundation for preventing and detecting of eccentric fault of motor.