Full Speed Range Control Of SRM Without Position Sensor

Switched reluctance motor(SRM)is a kind of variable reluctance doubly salient motor,which has simple structure and excellent performance,and is applied in many fields such as machine tools,wind power generation,metallurgy,coal mines,military industry,etc.The introduction of position sensor increases the complexity and instability of motor structure,and affects the reliability of motor.In order to solve the above problems,the sensorless control technology is gradually emerging.The practical application of this technology has certain engineering value,which conforms to the current technology development trend.This paper summarizes the research status of SRM technology,and focuses on the sensorless control strategy of SRM in full speed range.According to SRM operation principle,the sensorless control strategy is combined with phase sequence rotation control to realize the sensorless control of SRM in four quadrant full speed operation state,including start,low speed / high speed,forward / reverse,electric / brake.Firstly,this paper introduces the basic structure,operation principle and main control strategy of SRM drive system,summarizes the research status of SRM sensorless control at home and abroad by consulting literature,analyzes the advantages and disadvantages of existing sensorless control methods and their applicable application fields,and selects pulse injection method and flux linkage method as the research basis.Secondly,in view of the shortcomings of traditional single threshold pulse injection method,which only collects the peak value of current,and is easy to be affected by bus voltage fluctuation,electromagnetic noise interference,adjustment circuit drift,magnetic circuit saturation,etc.,a two-phase injection position free sensor control method based on current slope comparison is proposed.This method can effectively overcome the above problems,and is more accurate than single threshold pulse injection method It is suitable for engineering application,but it is only suitable for low speed operation.Then the paper analyzes and simulates the simplified flux method to solve the problem of high-speed control,and combines the improved pulse injection method with the simplified flux method,which has complementary advantages.The two methods are respectively responsible for the control of the low-speed and high-speed segments of the motor,and realize the full speed range of the motor from start,low-speed and high-speed segments.It is proposed that the motor can rotate forward in different speed stages The method of position estimation and commutation discrimination for four quadrant states ofreverse,electric and braking completes the control of SRM without position sensor in full speed range.Finally,the MATLAB model is established and simulated to verify the feasibility of the proposed method.