Study On Switched Reluctance Motor Control Without Position Sensor

With the development of electric vehicle and new energy technology,as well as the attention of the state to the shortage of resources and environmental pollution,the motor industry has come to its own spring.Switched reluctance motor(SRM),as a kind of motor with large starting torque,wide speed range,high efficiency,strong fault tolerance and low cost,is widely used in textile,oil exploitation,automobile manufacturing and other fields.Due to the special mechanical structure and non-linear electromagnetic characteristics of the switched reluctance motor,the position sensor must be used to determine the position of the motor rotor.However,the presence of position sensors limits the application environment of switched reluctance motors,but also increases the complexity and cost of the motor control system.Therefore,in this thesis,the Positionfree sensor technology of switched reluctance is studied,and the switched reluctance motor is expect-ed to be more widely used in industry.Firstly,the starting method and subsequent control of the switched reluctance motor without position sensor are studied and discussed.On the basis of pulse injection technology,the non-conducting phase current injection method is studied,and on this basis,the non-conducting phase current slope comparison method is further studied to make up for the non-conducting phase current injection method cannot meet the requirements of high-speed start.Subsequently,the slope comparison method of nonconducting phase current is improved.An inductance instead of current is proposed as variable control,and a double threshold method of non-conducting phase inductance is improved,and relevant experiments are carried out.This method improves the defect that the non-conducting phase current slope comparison method cannot open the angle ahead of time.The advantages of this starting method are high speed start,no inversion and adjustable opening angle.For the field of sensorless high-speed control,this thesis mainly studies the phase inductance slope method.Firstly,the special position point of switched reluctance motor is analyzed to determine the special position point of high-speed detection.Then,through the specific operation analysis,the problems of rotor position error pulse and unable to adjust the opening angle in the current phase inductance slope method are determined.Then,the logic of inductance partition is proposed to solve the above problems,and relevant experiments are carried out to determine the correctness of the theory.The experimental results show that this method can perfect the position free control method.Aiming at the blank of the research on the non-position braking method in the current research field of non-position control.Based on the improvement of phase inductance slope algorithm,a feedback braking control system is designed with adjusting the opening angle as the core,and relevant experiments are carried out to verify the correctness of the theory.The experimental results show that the braking process can be improved.At the same time,the fault-tolerant performance of the phase inductance slope algorithm is also studied,the phase failure operation is analyzed,and the phase failure operation strategy is proposed and verified by experiments.The experimental results show that the open phase operation strategy can complete the open phase operation.In this thesis,the start and subsequent control,high speed operation,braking and fault tolerance of sensorless switched reluctance motor(SRM)are analyzed and experimented,in order to promote the development and application of SRM.