Researching And Realizing Of The Brushless DC Motor Controller Based On DSP

The brushless DC motor has many features, such as small volume, light weight, high efficiency, little inertia, easy to be controlled, and so on. It|also keeps down the excellent machine characteristics of DC motor, so it(?)can be widely used in servocontrol, numerical control machine, robot, and so on. The application field of BLDCM has been enlarging, it requires the control system can work stably, cost down, control arithmetic reasonable, control exactly, short design cycle. So the BLDCM control system based on DSP has a broad application foreground.The TMS320C28x series is the most new DSP chip of TI up to now, it has strong ability in processing digital signals, so if it is used in the control system of BLDCM, the features of BLDCM will be showed clearly.This project is to study how to use TMS320F2812 to control the BLDCM. Therefor, I need to study on how to drive large power motor, how to protect the motor when it is working, and how to use the RS485 cable to communicate when need to use the PC to control the motor.With this core, this project makes a BLDCM controller, it can drive high speed BLDCM in 5kw power. The controller contains some perfect functions, such as over current alarm, air pressure,hydraulic pressure alarm, stop function, and when the speed of the motor over 30% compare with the command speed, then I will use dot brake to limit the speed.The control core is DSP TMS320F2812, and it also uses MC33035 to control and drive the motor. In the DSP control section, it takes on the control function of the whole system, including to check, control and show the speed of the motor, and start some other equipments to protect the motor. The DSP also needs to communicate with the PC. MC33035 needs to execute the dictate of the DSP, then output the signals to drive the motor, so to control the speed of the motor.This project wants to use the BLDCM with Honeywell sensor as position feedback. When the controller working, it collects the actual speed of the motor, then corrects the command speed, so it can control the speed of the motor in closed loop. The main speed control arithmetic is to use a rectangle window to filter the actual speed, then use PID arithmetic to correct the command speed. The main speed control idea is to collect the actual speed of the motor, compare with the command speed, then use PID to modify the command speed, so to let the motor can arrive at the target speed stably.This project makes a controller, and has been accomplished the debug. The whole control system includes two sections, one is the controller, the other is the operating system in the PC. The controller communicates with the PC through the RS485 cable, there are all function keys which is need to control the motor in the operating interface, it can control the motor easily through the PC. Except through the PC to control the motor, the controller also has a key can be used to adjust the speed of the motor, the theory is the same as the PC controlling.The result shows that the controller works stably, has a high control precision, the warp is mostly under the theory warp of 75 PRM, and can be operated easily, with perfect protect function and good load ability, so it can be widely used in some field.