Wuhan University of Technology DC motor control system

****Special Prize Team Name of Wuhan University of Technology Electronic Design Competition
: Tathagata Team
Members: Xu Yutong, He Jianwen, Wang Qiyuan
Instructor: Teacher Zhang Jialiang****

Entry Topic: DC Motor Control System
Design Report Document
1. Circuit Design
boost circuit design:
The LM5122MHX synchronous rectifier boost circuit is designed and produced by Lichuang EDA. It uses a sliding rheostat to adjust the output voltage. The circuit is hardware controlled and does not require software control. It is easy to use. The circuit schematic is as follows:

![image. png] Figure 2 Boost circuit schematic
motor drive circuit:
BTN7971 motor drive board has four channel outputs, which can realize motor forward and reverse rotation, dual-channel PWM wave control, and the integrated LM317 chip can be used as a single-chip microcomputer power supply and has current The function of feedback stable output and detecting the working status of the motor.


Auxiliary power supply:
The auxiliary power supply is filtered by a 2200μF filter capacitor and output by a three-terminal voltage regulator. A total of four positive and negative 12V adjustable outputs are set up. A sliding rheostat is used to adjust the output. The maximum output current is 1A, which can meet the power supply needs of the microcontroller.
![image.png] Figure 4 Auxiliary power supply schematic diagram of
constantan current detection circuit:
use constantan resistor as current load, use INA282 for voltage amplification, and change the DC bias to 1.5V by adjusting the sliding resistor to facilitate microcontroller sampling. When the current The voltage is greater than 1.5V in forward direction, and less than 1.5V in reverse direction. The schematic diagram is as follows:
![image.png] Figure 5 Schematic diagram of current detection circuit


![image.png]