The Control Strategy Of Switched Reluctance Generator

Switched reluctance machine(SRM)has the advantages of simple structure and low manufacturing cost as it does not need rotor windings and permanent magnets.Moreover,high fault tolerance and wide speed range make SRM a viable candidate for hash environment and high speed applications,such as starting /generator in aerospace and hybrid vehicle,and wind power generation systems.In this dissertation,the structure design software of SRM is optimized,providing a platform for the design of U-shaped stator cores SRM,and the control strategy of switched reluctance generator(SRG)is also studied in the aspects of theoretical analysis,simulation and experiment.With a large number of literature,this dissertation summarizes the development of SRM.The research of control strategy of switched reluctance generator(SRG)in recent years is also introduced,and then,the background of the issue is lead to.Secondly,the working principle,mathematical model and commonly used control methods of SRG are introduced based on basic structure.In order to provide suitable electromagnetic data for the research of SRG power generation control strategy,the structure design software of SRM in laboratory is extended in this dissertation,and the three-dimensional finite element analysis of U-shaped stator cores SRM based on ANSYS is presented.This process is written in the form of APDL command stream,which can be called by structure design software and then,the new motor structure can be designed.Users can also fully preview the motor structure and finite element mesh before magnetic field calculation with the optimized software.Some researchers believe that the single pulse control method(SPCM)introducing freewheeling technique,that is freewheeling control method(FCM),is helpful to improve the output power of SRG,however,this dissertation objects to that opinion.First,the theoretical analysis of the output power of SRG controlled in SPCM and FCM is presented in five different cases,according to relationship between the relative positions of optimal turn off angle in SPCM,freewheeling angle and turn off angle in FCM.The analysis shows FCM is unable to increase the maximum output power of SRG at a constant speed,which is verified through vast of numerical simulations and real-time experiments.The optimality condition for turn off angle in SPCM is also derived and verified in simulation.Secondly,simulation model of switched reluctance machine power generation system in M file is established,based on which,other performance in terms of efficiency,torque ripple and dc current ripple of SRG in SPCM and FCM are also analyzed and compared.Finally,output power,efficiency and dc current ripple of SRG in FCM are optimized at the same time with differential evolution algorithm.