Double Closed Lood Based On Proportional Integral Algorithm Brushed DC Motor Control Method

In recent years,with the rapid development of Internet of Things,more and more high-performance,high-quality,high-safety intelligent devices have entered the home,and market,including motor control products.Brushed DC motor is the main motor of motor control products.The performance,quality and safety of brushed DC motor controller with MCU as the core are directly related to the performance,quality and safety of motor control products.Therefore,improving the performance,quality and safety of the controller has become a hot research topic.At present,brushed DC motor controller products pay more attention to the motor control performance at rated speed,its control algorithm in the motor low-speed operation,the control effect is often reduced.In the speed closed-loop control of motor controller,the detection accuracy of speed feedback is an important factor affecting the good operation of motor in the low-speed region.At the same time,the motor may be out of control when the speed sampling error occurs.In view of the above problems,this paper develops a Proportional Integral double closed-loop control algorithm for brushed DC motor.(1)In view of the bad control effect of the motor when it is running at low speed,the speed correction value of the motor does not directly represent the control signal of the motor,but is used as the input value of the current loop to calculate the PI of the current return,which greatly improves the speed follow ability of speed controller.(2)In order to improve the accuracy of speed feedback in the speed control loop,the accuracy of axial angle variation of the motor can be improved to 0.9 degree.By comparing error analysis of the traditional motor speed measurement methods and choosing the external grating encoder.The sampling accuracy of speed and position is greatly improved,thus improving the control accuracy of the motor speed loop.(3)In order to improve the safety of motor control products,redundant design of motor speed sampling is added.First,the real-time speed of motor can be read out by external photoelectric encoder.At the same time,the voltage of motor armature can be calculated by sampling the voltage at both ends of the motor.According to theoretical analysis and mathematical modeling,the relationship between armature voltage and motor speed is obtained,and the motor speed sampled is compared with the calculated motor speed.The two sampling methods of motor speed are realized and redundant design is realized.Through the analysis of the experimental data of the designed controller,it can be concluded that the proposed control algorithm and the designed controller system can meet the application requirements of motor control products.At the same time,the designed controller improves the safety of motor control,the algorithm of the controller effectively improves the control accuracy,and the controller has obvious advantages in shape and size,and has good application value.