Research On Switched Reluctance Motor System Based On High Performance DITC Control

With the worsening of global environmental problems,people pay more attention toenvironmental protection and energy conservation.People prefer to use the renewable clean energy,such as electricity,in the choice of energy types.Switched reluctance motor,with its small starting current,high starting torque,low cost,stable and reliable operation,has attracted people's attention and gradually become one of the hotspots of research.But the switched reluctance motor also has its shortcomings.It is mainly due to the large torque ripple at the low speed operation stage,which limits its application and development in different situations.In this paper,it researchs on the control metheod which is called the Direct Instantaneous Torque Control strategy(DITC)that used to suppress the torque ripple of switched reluctance motor at low speed is studied.First,the structure,working principle and nonlinear model of switched reluctance motor are introduced.Then using FEMM to analyze the electromagnetic field of the prototype and obtain the characteristics of its magnetic chain and moment angle.According to the simulation data,the two single-phase synthetic torque and the actual torque are compared and analyzed,and the torque correction coefficient is obtained.The torque correction coefficient is used to make the torque correction,so that the synthetic torque obtained by the table is more accurate.At the same time,an adaptive torque hysteresis loop control strategy is proposed to optimize the traditional direct instantaneous torque control.According to the difference of torque and speed in the low speed operation stage,the torque hysteresis limit is adjusted adaptively according to the load torque and the speed adjustment coefficient,and the torque hysteresis compensation coefficient is added to change the rising rate of torque.In order to verify the effectiveness of the proposed strategy,a torque modified adaptive torque hysteresis DITC control system is built in the MATLAB/Simulink module.Through the simulation experiment,the current and torque waveform of the two control strategies are compared and analyzed.According to the results,the adaptive torque hysteresis loop DITC control system with the torque correction is more efficient in torque ripple suppression compared with the traditional DITC,which proves the effectiveness of the proposed strategy.The hardware circuit design and software system construction of SR torque direct torque control system with torque modified self-adaptive torque hysteresis are introduced.The hardware part introduces various functional circuits,such as rotor position signal detection circuit,power conversion circuit,protection circuit,sampling circuit and so on.The software part introduces the realization of torque correction coefficient,adaptive torque hysteresis,DITC control,motor protection,communication and other functions in the program.Finally,the experimental platform of SR motor high performance DITC control system is built to carry out experiments.The prototype used in the experiment is a 18/12 SR motor with rated power 5.5k W,rated speed of 1500r/min and rated voltage of DC 514 V.The experimental results show that with torque correciton and the adaptive torque hysteresis loop DITC control system can run steadily,the current peak is low,the change rate is small,and the torque ripple is reduced.When the torque changes abruptly,it can quickly transition to a new stable state.Compared with the traditional DITC control,the torque ripple suppression has a better effect.