Sensorless Control Of Switched Reluctance Motor Based On The Inductance Model

Switched reluctance motor is a new type of speed motor,with a simple structure,flexible control,fault tolerance and other advantages.The motor has been applied in some the fields.Real-time and the accurate rotor position information is a necessary prerequisite for reliable operation and high-performance control of the motor.Rotor position information is usually obtained by the position sensor.However,the position sensor increases the cost and complexity of the motor system,weaking the advantage of adapting to harsh environments and reduces the reliability of the system.Therefore,sensorless technology has important significance in research and engineering application.In this paper,the research status and achievements of rotor position identification technology of switched reluctance motor are described at home and abroad.The paper introduces the structure,working principle,basic mathematical equation and mathematical model of the motor,and the common control strategy and its characteristics are discussed.In view of the switched reluctance motors magnetic circuit saturation at practical work,a new control strategy for sensorless based on inductance typical positions in low speed operation is proposed in this paper.In order to simulate the inductance curves for the entire period of each phase winding,the motor phase winding take turns to turn on while the non-conductive phase is injected into high frequency pulse by using ANSYS,and then the full-cycle inductor curve is analyzed.It is pointed out that the algorithm based on the full period unsaturated inductance model can be used to estimate the rotor position with small current.When the conduction phase current is large,this method is a certain limitation.Based on the inductance model of injection pulse cycle,a method of estimating rotor position suitable for low speed operation and different saturation in the motor is proposed.When the motor is operated,the non-conduting phase is injected into high frequency pulse,thereby the whole period inductance information is obtained.The typical position points are obtained by the logical relation of the inductance,and the rotor position can be estimated by the typical position points,so the rotor position can be estimated.Due to the different load,the motor needs to consider the saturation of the magnetic circuit.However,the selection of location points in this paper is little affected by the saturation factor of the conduction phase when the load is carried,so the method can be operated under different load saturation conditions of the motor.The feasibility and correctness of the method are verified by simulations and experiments.The simulation model of the position sensorless control system is built by suing the Matlab/Simulink.The simulation results are in agreement with the theoretical analysis,which verifies the correctness of the method.Finally,a sensorless experiment platform is built.And the algorithm is verified by experiments.The experimental results show that the method is feasible.