Research And Design Of Brushless DC Motor Control System Based On KV31

At present,the motor in port machinery is still squirrel cage type three-phase asynchronous motor.With the construction of smart wharf and energy saving wharf,it is necessary to improve the energy utilization rate of port mechanical and electrical equipment.Brushless DC motor has been widely used in various fields because of its small size and high efficiency.Different from the traditional DC motor,the brushless DC motor must cooperate with the controller to rotate.The quality of the control system is very important to the motor performance.This paper takes the brushless DC motor and its application as the research object,analyzes and designs the precise modeling of the motor,the control strategy,the software and hardware design of the control system and so on,and provides a reference for the design of the port permanent magnet motor control system.Firstly,the mathematical model of brushless DC motor and its coordinate transformation are discussed.On this basis,combining with the principle of motor parameter measurement and engineering practice,the electrical parameters and mechanical parameters are measured,the specific values of parameters in the mathematical model are determined,and the precise mathematical model of brushless DC motor is established.Secondly,based on the vector control idea,a double closed loop control system is constructed.The speed loop adopts sliding mode control,and the current loop adopts PI control and i_d=0 control strategy.The simulation model is established in Simulink environment,and the parameters are adjusted according to the motor parameters.The simulation results of motor speed,torque and three-phase current are obtained,and the correctness of the controller scheme is verified.Thirdly,a complete control system is built with KV31F512VLL12 microcontroller as the core.In terms of hardware,the overall design of the hardware of the whole control system is carried out,and the selection of the main components is carried out,and the schematic diagram is designed by modules in Altium Designer software.According to PCB design rules and process requirements,PCB design,machining and welding.In terms of software,the initialization program,ADC interrupt program,PDB interrupt program and speed loop control task are designed based on the basic architecture of Free RTOS and state machine to ensure the reliability and real-time performance of the control system.At the same time,the final program design quality is measured by the statistics of CPU utilization.Finally,an experimental test platform was built,in which Freemaster was used as the upper computer software to control motor operation and monitor real-time data.According to the working condition of motor speed regulation with load and load impact in port machinery,the motor speed regulation experiment and step load experiment are designed to verify that the motor control system meets the design requirements.