Design Of Servo System For Brushless DC Motor Using DSP

This research is concentrated on high precision position servo control of a brushless DC motor (BDCM) using advance digital signal processor (DSP). The thesis' content includes system scheme design, servomotor selection, position control system design, hardware design and software design. The software and hardware are implemented for the tasks.In the design of system scheme, compute motor load, select control system components, and clarify principle of every component. The position servo control system is mainly consist of brushless DC motor with Hall sensors, harmonic reducer with big speed reducing ratio, TMS320F2812A advanced DSP, and Intelligent power module(IPM).In the design of position servo control system, the structure and principle of brushless DC motor are discussed in detail. The mathematic model of BDCM is founded. Base on the model, according to the expect performance index, design the control system, which contains current/torque loop design, speed loop design and position loop design. In order to reduce the delay of the position response, feed forward control is added to the control system. In addition, the system stability and frequency characteristic are analyzed.In control system hardware design, main power circuit, power drive unit, microcontroller and control unit, interface circuits are discussed respectively. The key point is on illustrating several important circuit designs and their component parameters selection.In control system software design, first, discuss TI DSP software development flow and several key programming problems; second, expound the idea of blocking program of control system; then, present main program and subprogram flow chart and some crucial program codes; at last, implement three-loop position servo system design.Finally, do some experiments on real system platform, to test the hardware and software of the servo system. Step response and sine tracking response are experimented, and present conclusions. The final results indicate that system work well and can meet expect target.