The Studies Of Brushless Motor System Design In Antenna Turntable Axis

This subject is originated from a project"antenna turntable", for the special requirements in a large reduction reducer of the drive motor control, commissioned by a company in Chongqing and specially designs a dual-axis and high-speed motor control unit.In this subject, because of the size, weight and power constraints, a chip special for brushless motor control must be dedicated as the master microcontroller. So the XC886 and XC866 are used as motor control chip. The main reason is that the XC886 and XC866 microcontroller has an important part CCU6 (Capture/Compare Unit 6), and the CCU6 has two independent timers used to generate PWM (Pulse Width Modulation) to address the special requirement of brushless motor control.According to the required parameters of the antenna rotation device project, the micro control unit circuit design, the rotor position signal acquisition circuit design, power circuit design, hardware protection circuit design, three phase full-bridge inverter and inverter driving circuit design are made in the hardware aspects with the XC886 and XC866 of infineon company as the controller. With hall sensors as rotor position sensors and according to the rotor position signal, micro control unit transmits PWM (pulse width modulation) and the inverter drive signal to the drive circuit to control the motor.In terms of software, modular programming and structured programming are made using C language. According to the control theory of brushless DC motor, the control section is analyzed in detail. It achieves closed-loop modulation of motor speed using digital PID control theory and the motor commutation angle, the hall phase and the motor output phase can be identified automatically. The design of the system over-current protection is made in system reliability. The paper also analyzes the factors affecting the reliability of the system controller and the microcontroller and gives solutions.The brushless DC motor controller implements the motor rotation and speed closed-loop PID control. The control system has a better protection function, low cost, convenient secondary development for users and hardware structure is simple.