Research On Optimization Of Direct Torque Control Strategy Of Switched Reluctance Motor

With the rapid development of the new energy automobile industry in various countries,the drive motor as the core component of the new energy automobile has been further developed by the majority of car dealers and scholars.Among them,the switch reluctance motor has a solid structure,a large starting torque,and a low cost.It is reconsidered to be used in the drive of electric vehicles.However,the specific shortcomings of the motor such as large torque ripple and high noise also limit the application range of the motor.This paper summarizes the current research status of switched reluctance motors,drive circuits,control strategies,etc.,and starts with the shortcomings of the large torque ripples of switched reluctance motors,and derives that direct torque control has a good effect on suppressing torque ripples.Taking the four-phase 8/6-pole switched reluctance motor as the research object,the research is carried out from the theories of motor structure,working principle,mathematical modeling,etc.,to lay the foundation for motor body modeling and control strategy optimization.Study the working status and commutation process of the five-phase full bridge circuit,and pave the way for the combination of improvement strategies.According to the parameters of the experimental motor,the magnetization characteristic curve is simulated in the finite element software,and the magnetization data is imported into the motor model to obtain the corresponding relationship with the experimental motor.The theoretical analysis of each part of the traditional direct torque control is carried out,and the system simulation is built.The simulation results are analyzed and the reasons for the further reduction of the limiting torque ripple are put forward.In the direct torque control strategy based on sixteen sectors,the effect of sector subdivision and the new sector on winding commutation is studied.The analog voltage vector switching process is compared with the traditional strategy,and the new strategy switch table and system simulation model is designed and built.Theoretically verify the simulation waveform of the new strategy and compare it with the traditional strategy.In the direct torque control strategy based on the three-vector flux linkage,the influence of the zero vector flux linkage synthesis method on the winding commutation is analyzed.The analog voltage vector switching process is compared with the traditional strategy to illustrate the difference in switching frequency.The new strategy switch table and system simulation model is designed and built.Theoretically verify the simulation waveform of the new strategy and compare it with the traditional strategy.In the direct torque control strategy based on the torque distribution function,the conversion process between the partial torque of each phase winding and the total torque is studied,the cosine function is established,and the conduction angle,the turn-off angle and the overlap angle are reasonably designed according to the inductance period.The system simulation model is designed and built.Theoretically verify the simulation waveform of the new strategy and compare it with the traditional strategy.Finally,combined with the existing experimental equipment,build a switched reluctance motor experimental platform with DSP as the control core,explain the selection of the control circuit,sampling circuit,and drive circuit,and design the software program of the direct torque control strategy based on the torque distribution function,the overall development and debugging were completed on the hardware platform,and the experimental waveform was theoretically verified,which proved the effectiveness of the optimization strategy.