| The brushless DC motor (BLDCM) adopts electronic commutation instead of mechanical one, which overcomes a series of disadvantages of the traditional DC motor caused by the brush friction. Furthermore, with many advantages such as good speed regulating performance, small volume and high efficiency, it is widely applied to every field of national industry and people's daily lives.In terms of control strategy of BLDCM, the most obvious characteristic of the fuzzy control which is based on intelligent control is that it doesn't rely on the object model, but utilizes the rules set by fuzzy control to make reasoning in order to get proper control value. However, it is difficult to eliminate the steady-state error with fuzzy control, because it doesn't contain integral units. Therefore, this control system combines the traditional PI control with fuzzy control, expecting to obtain better dynamic and static performance.Based on BLDCM's mathematical model, the simulation model of control system is build, and simulated in Matlab Environment. The simulation results indicate that the Fuzzy-PI control system has fast dynamic response, smal overshoot and excellent reliability.Based on the simulation, the current and speed double closed loop control system of BLDCM based on ADMC401 is deigned. The speed regulation is realised by adjusting the terminal voltage of the motor. In this system current is regulated by PI controller and speed is regulated by Fuzzy-PI controller. Compared with classical PI controller of which the parameters are fixed, Fuzzy-PI controller can regulate the parameters on-line according to current status of object controlled, and the control performance could be enhanced.After the hardware and software of the system have been debugged, the experiment is carried out, and the advantage of Fuzzy-PI control over classical PI control is further verified by the experimental figure. The entire system is evaluated in the end, and opinions on the existing problems of BLDCM's Fuzzy-Pi control technique and further studies are put forward. |
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