Research On Position Indirect Detection Control System Of Switched Reluctance Motor

Switched reluctance motors(SRM)is simple and stable in structure,low in cost and easy to control,so its advantages are particularly prominent in the face of high temperature and high-speed dust and other adverse conditions.It is widely used in mine traction,textile machinery,aviation industry and other fields.Position sensor plays an important role in SRM speed control system,but it will increase the cost of system and weaken the stability of motor operation,which limits the application of SRM.Using indirect position detection instead of position sensor can overcome the above shortcomings,but this method has different control methods in the start-up and operation stages of the motor.According to the characteristics of the operation stage,the methods of indirect position detection and improving the detection accuracy are researched in this paper,which is of great significance to the speed control system of SRM.In order to study the indirect position detection scheme of SRM,the nonlinear model of SRM needs to be built.In this paper,the electromagnetic characteristic curves of all positions are obtained by the method of partition analysis and fitting based on the special position flux data.On this basis,the nonlinear flux and torque model of SRM is established.The simplified flux linkage method,which is commonly used in indirect position detection of SRM,cannot realize the multi-phase conduction operation and continuous position estimation.In this paper,an improved indirect position detection control scheme is proposed:the flux model at the off position is used to replace the traditional data table and the off position signal is obtained through the flux comparison,so as to realize the speed and other position estimation.Considering the nonlinear characteristics of winding voltage drop and inductance,the optimal regulation model of opening position is established to optimize the efficiency under different operating conditions.In order to improve the detection accuracy of the proposed scheme,the characteristics of flux change in the current conduction stage are analyzed.Based on the current chopper control,a current hysteresis PWM subsection control scheme is proposed.On the basis of theoretical research,MATLAB/Simulink platform is used in this paper to simulate and compare the simplified flux method and the improved indirect position detection control scheme.The results show that the proposed scheme can accurately obtain the speed and rotor position and improve the operation efficiency of the motor under different working conditions.In this paper,three-phase 12/8 switched reluctance motor is used as the control object,TMS320F28335 DSP is used as the control core to build the hardware experiment platform.Under the compiling environment of ccs6.0,the algorithm program of control system is designed and debugged.The experimental results shows that the proposed indirect position detection control system can obtain the speed and position information effectively and the motor can run stably under different speed load conditions.