Wuhan University of Technology DC motor control system

Wang Zhuoer, Liu Zijian and Guo Jie, the third-prize winning
team in the WHUT-13th Electrical and Electronics Innovation Design Competition , required that (1) the system use +12V power supply and make a boost circuit to provide +15V power supply for the motor. The boost circuit requires a maximum error of output voltage of ±3% and a maximum output current of ≥3A under resistive load conditions. Under full load, the efficiency is ≥90%, and the ripple is less than 200mVpp; under inductive load (DC motor no-load movement), the maximum error of the output voltage is ±6%, and the ripple is less than 500mVpp. (15 points) Improvement part: When all the above indicators are met, if you can achieve obvious optimization of at least 3 indicators (accuracy, load capacity, etc. are doubled, the ripple is reduced by half, and the efficiency is increased by 5%), you can get additional Add points. (5 points) (2) Make an auxiliary power supply that meets the normal working requirements of the system to power the microcontroller, measurement system, etc. The system quiescent current is required to be less than 5mA. (That is: the system needs to reduce power consumption as much as possible when there is no test task. During system testing, an ammeter will be connected in series to the input end to monitor the system operating current). (5 points) (3) Make a motor drive circuit that can realize motor polarity switching (forward and reverse switching), output instantaneous maximum current ≥10A, rated current ≥5A, and working voltage 12-24V. (10 points) (4) To make a motor current detection circuit, the system requires a single power supply, the current monitoring accuracy is better than 1%, and when the current changes dynamically, the monitoring bandwidth is >1KHz. The detection results are transmitted to the computer for display through the wireless transmission module. (20 points) (5) Use the encoder speed feedback method to control the movement of the motor and pull the 1KG object vertically to achieve the following movement process: stationary - acceleration - uniform speed (the speed of uniform movement is determined by yourself according to the actual situation). In the process of rising at a constant speed, by increasing the weight of the object, when the motor current reaches or exceeds 150% of the current when a 1KG vertically pulled object rises when the constant speed is restored, the buzzer is controlled to implement an overload alarm. In the process of falling at a constant speed, by increasing the weight of the object, when the motor current reaches 50% of the current when the object of 1KG is vertically pulled down, the buzzer is controlled to implement a stall alarm. (15 points) Note: The total weight of the object does not exceed 2kg, and the added object has no initial velocity. (6) Use the current feedback method to control the movement of the motor and pull the 1KG object vertically to achieve the following movement process: stationary - acceleration - constant speed. When at rest, start by pressing the button to realize the rest-acceleration process. The acceleration movement distance is 0.3 meters (strictly guaranteed), the final speed is 0.3 meters/second, the uniform movement distance is 1 meter, and it will decelerate and stop immediately after exceeding 1 meter (do not do this) requirements), rise and fall independent testing. (15 points) Note: During actual scoring, the encoder in (5) needs to be in a non-working state; if the motor movement is controlled by using encoder feedback to meet the requirements of this question, no points will be awarded. (7) The motor needs to have a speed detection function (absolute encoder, etc.), and a self-made speed and distance measurement display system is required, and the instantaneous measurement results are transmitted to the PC through the wireless module for verification. This part of the circuit system is required to be powered and work independently, and have no electrical connection with the above control system, drive system, etc. (that is, it must not share power or ground with the motion control system). The evaluation process will be compared with standard instruments and equipment. (15 points) The work encoder speed feedback method/current feedback type DC motor control system and test system 12V-15V DC-DC power supply uses three MC34063 boost modules in parallel to increase the output current. The 5V auxiliary power supply uses the LM7805 chip and is filtered by a parallel capacitor. The driver board is based on BTS7960. This work uses a combination of software and hardware, which not only meets the flexibility requirements of control but also satisfies the characteristics of fast response. Judging from the results of simulation and physical testing, the control system is effective and can Reflect the input and output characteristics and speed modulation requirements of the actual system. In summary, this design 1. The motor control sensitivity is high and the PID algorithm is stable. 2. The power output capability is strong and the auxiliary power supply is stable, meeting the requirements of the question. 3. Both motor drive circuits have an output of more than 5A under normal no-load conditions, and can reach 12A/60A output under extremely high loads. 4. The distance measurement and speed measurement circuit is equally accurate according to the simulation and meets the requirements.