Speed Control Of Brushless DC Motor Using Immune Feedback Mechanism

The brushless DC motor (BLDCM) has been widely used because of its excellent performance such as its particularly high mechanical power density and effectiveness. However, because of the even high requirement of many applications, many researches are focused on the improving of the control strategy of the BLDCM.The brushless DC motor is a multi-variable and non-linear system. Conventional PID control can not obtain satisfied control effect. This dissertation presents a novel control approach for BLDCM by using artificial immune feedback mechanism. It introduces an immune feedback PID controller based on fuzzy model. This novel controller is inspired by the biological immune feedback mechanism based on the functioning of T-cells, including an active term, which controls response speed, and an inhibitive term, which controls stabilization effect, and we employ a fuzzy logic to implement the inhibitive term. Then we combine it with PID control to make sure that the control can be not only self-tuned but also without static error. Also, the system includes current and velocity closed loops. The whole BLDCM control system is simulated by MATLAB. Based on the BLDCM model, the simulation of fuzzy immune PID control system is then set up. The result of the simulation illustrates that excellent flexibility and adaptability as well as high precision and good robustness are obtained by the proposed strategy, especially when compared to PID control strategy. In additional, an ANN controller based on immune feedback adaptive learning is presented, and the controller is applied into the BLDCM velocity control. This application of the immune feedback law to the tuning of learning rate improves the gradient descent NN learning algorithms and speeds up the convergence significantly.For experiment, the research designs the control system of BLDCM based on TMS320F2812 DSP (Digital Signal Processor). This design divided into software and hardware design, which include drive and inverter circuit, sampling circuit, serial communication, PWM control and speed regulating. Also, an elevator door motor system using BLDCM is introduced. Lastly, the experiment results prove that the control system has excellent performance.