Research And Realization Of Braking Control For Switched Reluctance Motor

Switched reluctance motor(SRM)has a wide speed range,frequent start and stop,brake,frequent positive and negative switching and many other advantages,become the latest generation of speed control system.In this nearly 20 years,the domestic and foreign carried out a lot of research for the switched reluctance motor body design and speed control system,made a lot of results,However,there are few researches on the braking operation of switched reluctance motor.In this paper,a three-phase 12/8 structure 3k W switched reluctance motor as a control object,its braking stop and forward and reverse fast switching operation were studied.Firstly,based on the understanding of the working principle and the principle of electromechanical energy conversion,aiming at the characteristics of nonlinearity which was difficult to model,quasi linearization and linearization,the variation of flux linkage and phase current in quasi linear model is analyzed,a small signal model was established to set the speed regulator with the PI control method.In the brake operation,the linearization model is used to analyze the change of current,and the three control methods are compared and analyzed.The voltage chopping and current limiting method is adopted to solve the problem that the current is more likely to damage the power devices.Secondly,the design of SRM drive system hardware and software is completed through theoretical analysis.Hardware mainly includes the following modules: power converter main circuit,drive circuit,drive protection circuit,current sampling conditioning circuit.The software includes the main program,the timing interrupt subroutine,the capture interrupt subroutine,and the communication module.This paper focuses on how the SRM is running fast and backward and fast braking,for the problem of insufficient torque in the reversal process of forward and reverse fast switching,the method of combining signal and double lines is adopted,and the method of judging the actual sterring is given.A three-phase continuous communication brake combined with signal-phase braking method is used to solve the problem of possible braking reversal in the brake stop operation.Finally,through the hardware combination of software testing experiments,the relevant waveforms and curves of the switched reluctance switch and the brake stop operation are given,and the analysis is carried out,the results show that SRM has good braking performance and fast switching performance.It has laid a certain foundation for the further study of SRM speed control system and its application.