| With the development of science and technology,efficient and stable motors are more and more concerned by experts from all over the world.Switched Reluctance Motor(SRM)has the advantages of high work efficiency,strong reliability and simple mechanical structure,and is widely used in aviation power manufacturing,flywheel energy storage technology,hybrid vehicle drive,other industrial manufacturing and people’s lives.However,due to its unique structure,there is a problem of large torque ripple during operation,which limits the further use and popularization of SRM.In order to reduce the torque ripple,the direct torque control(DTC)algorithm has been widely used in the motor control system because of its advantages of being intuitive,concise,and relatively fast in calculation speed.In this paper,the causes of DTC torque ripple of switched reluctance motor are analyzed,and a direct torque control system of switched reluctance motor based on minimum voltage vector deviation is proposed.The analysis was carried out under different working conditions,and the experimental platform of the pole and 5.5k W motor was built to verify the method.The pulsed power supply mode is used in the SRM operation process,and there is a commutation process between each phase.Due to the existence of the inductance parameters in the phase windings,the commutation current cannot change abruptly,there is a commutation delay,and the rate of change of the two-phase inductance in the commutation area is also inconsistent,the total torque of the front and rear two phases is smaller than the torque of single-phase operation,and the total torque is reduced.In order to solve this problem,the conduction phase is turned on in advance in the commutation region of the motor,and an improved direct torque control method with increasing voltage vector is proposed.Increase the output torque and reduce the torque ripple amplitude in the commutation area.In the process of basic voltage vector control of traditional DTC,only one voltage vector is working in each control process.During this process,the changes to torque and flux linkage are fixed,which will cause the system torque to increase excessively during control,so it causes large torque and flux fluctuations.In order to solve this problem,a direct torque control system of switched reluctance motor based on minimum voltage vector deviation is proposed.The system does not contain flux linkage and torque hysteresis.According to the change process of flux linkage and torque,double PI links are added for adjustment,after calculating the reference voltage vector,select the location of its sector,and a non-zero voltage vector is selected.Based on the minimum voltage deviation between the two,the inverter outputs zero voltage and non-zero voltage vector to act on the motor,suppressing torque ripple.Completed the simulation of the improved voltage vector switch module and the minimum voltage vector deviation module in The traditional direct torque control of deviation is compared under different working conditions to verify the reliability and superiority of the proposed algorithm.Built the SRM speed regulation system controlled by the DSP chip TMS320F28335,and the power conversion circuit,driving circuit,current and voltage detection circuit and software design process are described.The experimental test is carried out,and the experimental current and torque waveforms are compared with the simulated waveforms,which verifies that the method proposed in this paper can reduce the torque ripple of SRM very well. |
