Research And Design Of The BLDCM Driver Based On DSP

The Brushless DC motor system is constituted by the permanent magnet brushless motor,electronic commutation and speed control device. The permanent magnet brushless DC motoris a new motor emergenced with the development of permanent magnet rare earth materials.Its rotor is made by rare earth permanent magnet materials, and its mechanical commutationis instead by electronic commutation, therefor it has both the advantages of traditional DCmotor, such as speed performance and torque density, and the advantages of AC motor suchas the simple structure, easy maintenance and operating efficiency etc. Brushless motor driverusing DSP technology designed either to change the phase but also the governor.It is used inthe servo system, high-precision position control system and other high-tech fields more andmore widely, therefore it becomes a hot topic.The paper first introduces the theoretical knowledge of the overall structure, operationprinciple, mathematical models, and mechanical properties of the brushless motor system.Then researched knoledge of the causes of torque ripple, torque ripple suppression method,brushless motor braking and PID control principle in the brushless motor speed controlsystem，also it simulated the speed regulation and torque regulation of the speed controlsystem. On the basis of theoretical analysis and simulation studies, according to the technicalrequirements, a 5.5KW brushless motor driver has been designed. The hardware designinclud schematics and PCB drawing of the hardware DSP system, CAN bus interface circuit,the switching power supply circuit, drive circuit and power conversion main circuit. Thesoftware design contain the main program, the CAP interrupt subroutine, the CAN interruptsubroutine, the A/D interrupt subroutine, the timer interrupt subroutine and the commutationcontrol sub-program. Finally, system debugging, and adjust the PID parameters according tothe actual situation and braking duty cycle parameters to optimize the control performance,and verify the correctness and feasibility of the system, laid the foundation for in-depth study of the system and further optimization.The control part of the system is at the core of TMS320 F2808 DSP, and IR2132 andsupporting circuitry composed driver circuit, and UC3844 and supporting circuitry composedflyback switching power supply. Through field trials, the design can achieve a constant torqueof the motor running, a constant speed operation and communication functions of the PCthrough the CAN bus to control the driver. In the design process, it takes into account themotor torque ripple, the back brake and high current drive. This design has met the designrequirements and achieved the desired goal.