Sensorless Control Of Switched Reluctance Motor Based On Inductance Method

Switched Reluctance Motor(SRM)has many advantages,such as simple structure,high reliability,flexible control,wide speed range and strong fault tolerance.It is widely used in electric vehicle and aviation industry.However,for the SRM control system,accurate rotor position information is a necessary prerequisite for implementing advanced control algorithms.At present,the mechanical position sensors are used to measure the rotor position information of SRM,which increases its volume and the complexity of the system.In addition,it can not be used in some harsh environments such as high temperature and high dust,which greatly limits the application field of SRM.Therefore,sensorless control technology of SRM has become one of the research hotspots for scholars at home and abroad,which has certain theoretical and practical significance.Firstly,the nonlinear flux linkage characteristic curves of SRM were measured by static locked-rotor test.According to the basic equation and the data of flux linkage characteristic curves,the nonlinear dynamic simulation model of SRM is built in MATLAB/Simulink.Then,based on the logical relationship of three-phase inductance,two simple sensorless control methods are proposed,which use the estimated driving signals and the rotor position angle to realize the sensorless operation of SRM respectively.Simulation results exhibit that the correctness of the two algorithms.Secondly,two improved strategies are proposed to solve the problem of inaccurate position estimation caused by the influence of magnetic saturation on the traditional inductance special position method.The first method is to reduce position error by neglecting the special position points which are greatly affected by magnetic saturation and estimate the rotor position only by the points which are less affected.The other method is to calculate the error angle by pre-fitting function and compensate it to improve the estimation accuracy.Finally,the estimation errors of three algorithms are compared by simulation.The results show that the improved algorithms can effectively reduce the error and estimate the rotor position more accurately than the traditional methods.Finally,the hardware and software design schemes of the SRM control system are expounded.The main hardware circuit and key software program flow chart are given.The SRM hardware experiment platform is built to verify the sensorless algorithm proposed in this paper.Experimental results show the proposed methods can well realize the sensorless operation,reduce the estimation error to some extent and further improve the position estimation accuracy.