The Study Of Control System For Brushless DC Motor Using DSP Technology

Brushless DC motor(BLDCM)with permanent excitation, in which electrical commutator is used instead of mechanical, has not only the same good characteristics of speed control as traditional DC motor, but also the good characteristics of AC Motor. Brushless DC motors have found wide application due to their high power density and ease of control. Moreover, the machines have high efficiency over wide speed range. Recently it has been quickly developed. In view of above-mentioned reasons, this thesis makes a detailed study on the control technology and methods to BLDCM.In this paper, the details of brushless DC motor component and fundamental principle was introduced, the brushless DC motor speed control methods are analyzed and studied. The feasibility of the United States TI's 32-bit fixed-point DSP, TMS320LF2812 as a micro- controller was discussed. The theory of hall signal checking and how to change phase using DSP technology are discussed in detail and analyzed the method of using a single resistance measure phase current. According to the design of the hardware circuit on the specific structure and method, the DSP external circuit was discussed in detail. 74LVTH16245 and CBT3384 were used in DSP interface circuits. Selected Intelligent Power Module IPM as the power switch components, and HPCL-4504 was used in drive unit for IPM, which made the control system segregation with the main circuit and the operation of the system more secure and reliable. At the same time the system software were designed and the analysis with software modules was given. The problems and the solution which meet in task were mentioned. At last the system debug process and the running results were described.