Research On Modeling And Control Of Switched Reluctance Motor Based On Analytical Method

With the development of economy and society,the energy requirement is growing, enhancingpeople’s awareness of energy conservation. At the same time, thanks to theimprovements ofscience and technology, lots of new electric drives constantly come into view. Switchedreluctance motor (SRM) is a new motor developed in this context. Compared with traditional ACand DC motors, SRM has a simple structure, low cost, superior performance and many otheradvantages, causing widespread concern in the industry. It is mainly attributed tosome defectsofSRMthat the market development ofSRM still did not meet expectations so far. The difficulty toobtain the mathematical model of the motor and the presenceof large torque ripple are two of themost serious shortcomings of SRM. Therefore, mathematical modeling and torque ripplesuppression are important research topicsof SRM.Firstly, the basic structure and operating principles of SRM are introduced. The circuitequations, mechanical equationsand electromechanical energy conversion equations of SRM arederived, whichare under linear and nonlinear conditions respectively. The nonlinear equationgives the complex and nonlinear coupling relationship between the internal variables. Based onthe nonlinear coupling relationship, the research objectives are submitted, which aremathematical modeling of flux and torque characteristics of SRM.Secondly，in order to obtain the flux and torque characteristics of SRM, an experimentalcircuit to detect flux and torque characteristics is designed. In the procedure of the experiment,the rotor of the motor is locked, while a pulse voltage is applied to the motor windings to get theflux-current and torque-current characteristics of each position. Thereby, a completemultivariable nonlinear relationship of flux-current-angle and torque-current-angle can beobtained, which lays the foundation for the mathematical modeling of the motor.Then the mathematical model of flux and torque behavior is established,based on the fluxand torque data measured from the detection experiment. The curve fitting is adopted for themodeling with the least squares method to acquire the analytic function of flux and torquerespectively,and the arguments of the function are thephase currents and the rotor angle.Moreover, a sub-fitting method to improve the fitting precision of torque model is presented.Finally, a simulation platform with Matlab/Simulink is built to simulatethe operation ofSRM based on the experimental data of flux and torque characteristics. The torque sharingfunction method is applied to reduce the torque ripple of the SRM.Simulation results certify the correctness and validity of the torque sharing function method for torque ripple suppression.