| Brushless DC motor has many advantages including reduced weight, low cost, long using life and low maintenance, which has been widely utilized in many fields.In this paper, based on the construction and principle of the brushless direct current motor (BLDC), the mathematical model of BLDC are presented. To improve the traditional Back-EMF theory of monitoring the position of the rotor, this paper has proposed a new method relied on Back-EMF by different between two-line voltages, and designs the hardware detecting circuit. Then it analyzes the question of BLDC starting, and proposes a new starting procedure of the stepping-changed phase's method of starting. Furthermore, this paper discusses the three stages of the two pre-localizations, accelerating and switching in detail. In other to increase the precision and stability of the control system, this paper employs control strategy of the double closed loop, a PI controller used in the speed loop and a hysteretic current controller used in the current loop.In the end, the hardware system of BLDC is built by the TMS320LF2407A, and then the software is compiled in CCS. The experimental results have shown that designed BLDC speed control system is wide speed range, moving steadily, and meets the anticipated requirements.
|
PDF Full Text Request