Study On Sine Wave Subdivision Drive Of System Of Three Phase Hybrid Stepping Motor Based On DSP

There are some disadvantages such as oscillating and losing step in traditional open-loop driving control system of three-phase hybrid stepping motor. In this paper three-phase hybrid stepping motor is regarded as a kind of low-speed synchronous motor by the analysis of the idealized three-phase hybrid stepping motor's mathematical model. According to the working principle of the current-tracing type PWM technology and the driving method of permanent current, this dissertation designs a fully digital three-phase hybrid stepping motor subdivision drive system based on the digital signal processor TMS320F2812.First, the appearance of subdivision driving for three-phase hybrid stepping motor is studied profoundly based on the mathematical model. At the same time, the mechanism of the stepping motor's rotating evenly is analyzed. Then the operating performance of the hybrid stepping motor and the necessity of the subdivision control and how to improve the performance of stepping motor are analyzed. Further more, the stepping motor's subdivision with permanent torque controlling method is put forward to improve the traditional subdivision's disadvantages. The results shows that the hybrid stepping motor and the synchronous motor have similar torque characteristics, on condition that the three-phase stator windings are input sine-wave current being lack of 120 electric angle each other, which make hybrid stepping motor rotates evenly.In hardware circuits of this system, the core processor is Texas Instrument's high performance DSP TMS320F2812. Also this drive system adopts sine-wave current subdivision and current tracking PWM technology so that the current in the three-phase stator windings can follow the change of the current signals given strictly. Because of the application of IR2130 in the power driver circuit, the volume of the product is reduced dramatically. Meanwhile according to the reliability of the product, a set of simple and reliable protection circuits has been designed.The experimental results indicate that the sine-wave current subdivision driving control system for three-phase hybrid stepping motor has superior control characteristic. It can reduce oscillating and noise of hybrid stepping motor, and can improve the stepping motor's performance in low-frequency scope.