The Research Of Direct Torque Control Speed Adjusting System For Switched Reluctance Motor

Switched Reluctance Motor(SRM) has great potential for development with the control flexible and simple structure. Thus more and more scholars pay attention for it. But the SRM application has not been promoted, it is because the switch in the form of electricity and doubly salient structure which has led to a large torque ripple and noise problems in the control. In this paper, to improve the speed performance of the motor, the switched reluctance motor control performance is optimized from the control strategy and structure.On the analysis of SRM operation principle, the SRM flux and torque equation is deduced through the derivation of the basic mathematical equations of SRM. In the control strategy, the torque and flux is limited in a hysteresis loop thought direct torque control(DTC).In the structure, the four-phase SRM and five-phase SRM is selected to comparison. Than the switch table of five-phase SRM and four-phase SRM is deduced on direct torque control. A five-phase SRM direct torque speed control system model is built in MATLAB / Simulink simulation environment. The four-phase SRM’s steady control current is larger by contrast simulation experiments. In order to optimize the problem, the four-phase SRM direct torque control has been improved and the variable flux control method is introducted. So, to some extent, the motor’s efficiency is improved.Although the five-phase SRM improved torque ripple from the structure, but the increase in the number of phases will inevitably lead to more serious internal nonlinear and control more difficult. Therefore, this paper introduces the BP neural network PID control(BP-PID) in the five-phase SRM direct torque control, it with conventional PI compound as a speed regulator. The Switch is achieved between them is based on the speed error limits. In order to improve the system’s fast, a variable parameter control method is introducted in the conventional PI control, the difference between the traditional limits of speed error but by the margin of error to achieve load torque change the parameters of the PI.Finally, the overall implementation of SRM speed control system is designed. In the hardware, based on TMS320F2812 controller, the hardware and software flow chart are designed. Than achieve a current chopping start under two-phase control.