Research On Eddy Current Sensor Detecting The Position Of Switched Reluctance Motor

The switched reluctance motor(SRM)is widely used because of its simple structure,high reliability and other outstanding advantages,and the position detection is a very important part in SRM control system,which detects the position and the rotational speed in time for to ensure the normal operation of the motor.The SRM position detection system includes direct position detection and indirect position detection.As the electrical function relationship of the indirect position detection is very complicated,and the direct position detection is still used in practical application.The direct position detection sensors include photoelectric,hall type and electromagnetic type.In actual use,the photoelectric sensor is not suitable for oil and high temperature environment.The hall sensor is also not suitable for high temperature environment,and its electromagnetic interference is very seriously.The electromagnetic rotary transformer can work in high temperature environment accurately,but its price is high,and the volume and weight is large.The eddy current sensor(ECS)can work in high temperature environment,and it has small size,light weight,high detection accuracy,so this paper we choose the eddy current sensor as SRM position detection sensor.The eddy current sensor has been widely used in all walks of life,such as non-destructive testing,displacement detection.But there are little research about the ECS detecting the motor position,so this study is of great significance.In this paper,the electromagnetic characteristics and output characteristics of ECS are analyzed by theoretical analysis,numerical analysis and experimental verification.Firstly,the output characteristic and the influence of the parameters of ECS detecting the position are analyzed by theory.Secondly,establish the three-dimensional model of SRM detecting the position by using the finite element simulation software ANSYS,and then verify the feasibility of it.Based on the established finite element model,analyzing the influence of the parameters,such as exciting signal,probe coil size,position disk related on the output impedance characteristics of the switched reluctance motor position signal detected by the ECS,and obtain the trend of the output impedance and the sensitivity of the detection varies with each parameter,which can be used as the main basis for optimizing the ECS.At last,design the eddy current sensor and set up the motor position signal experimental platform to verify the theoretical analysis and numerical analysis.