Research On Simulation And Suppression Methods Of Electromagnetic Radiation Of Motor

As the executive part of the drive system,the motor is more and more widely used in industry,military and other fields.When driving device and electronic equipment are in the same system,the radiated interference produced by the motor will have a great impact on the surrounding electronic equipment.For example,in the electric vehicle,the radiated interference produced by the driving motor will be coupled to the circuits of motor control system and other electronic equipment,and then cause a great impact.Therefore,China has formulated standards for vehicle radiation.As one of the main electromagnetic radiation sources of the whole vehicle,the driving motor produces electromagnetic radiation which has gradually drawn more attention.Aiming at the electromagnetic radiation of the motor,this research mainly studies the following aspects:(1)Because of the complex structure of the motor,firstly,this research analyzes the structural characteristics,working principle of the motor and the interference source of the motor radiated interference.Then this research analyzes the interference source and the main coupling ways of the motor radiation interference in the drive system to learn how electromagnetic radiation radiates from the motor and enters other equipment.At the same time,the propagation paths of common mode current and differential mode current in the motor drive system are summarized.Finally,several common methods of motor radiation suppression are introduced.(2)Taking a permanent magnet synchronous motor as the research object,the parallel motor windings are simplified to a single conductor based on the Equivalent Cable Bundle Method.The parameters of self-inductance and section radius of the single conductor are calculated,which provides a theoretical basis for the simplification of three-dimensional modeling.The current signal in the three-phase line is tested by the current clamp,and the signal is used as the simulation excitation source.This research uses the CST Cable Studio to simulate the electric field emission of winding and simplified conductor.Finally,the correctness of winding simplification is verified by comparing the calculation results.(3)Based on the geometric parameters of the single conductor and the actual mode of winding,the simplified three-dimensional model of the motor is established.Through CST Microwave Studio,the three-phase signal is used as the excitation source,and the Finite Integral Method is used to simulate the electric field emission of the motor.In the anechoic chamber,the electric field emission of the motor is tested.Finally,according to GB/T18387-2017 standard for electric vehicle radiation,the simulation results are compared with the test results of 0.15-30 MHz band electric field emission.It verifies the effectiveness of modeling and simulation methods.(4)This research suppresses radiated interference of the motor by filtering and shielding.It designs a third-order Bessel low-pass filter of inverter based on the normalization low-pass filter.According to the calculation and comparison of the electric field emission of motor before and after filtering,the suppression effect of the filter is verified.This research improves the motor shell based on the shielding theory.On the basis of the calculation and comparison of the electric field emission before and after the shell improvement,the effectiveness of the shell improvement measures is verified.