Design Of Asynchronous Motor Soft Starter Based On Fuzzy PID Control

Asynchronous motors have many advantages,such as simple structure,low cost,reliable work,so they are widely used in various fields of the modern society.However,the performance of the asynchronous motor starting is not very ideal,and a large rush current will be generated during direct starting,which will cause serious damage to the motor itself and the load.In order to suppress the inrush current of asynchronous motor starting and improve the performance of asynchronous motor starting,this thesis adopts fuzzy PID control algorithm and uses STM32 microcontroller as the core processor to design the asynchronous motor soft starter.Firstly,this thesis introduces the background of the asynchronous motor soft starter and the current research status at home and abroad,and then analyzes the fundamental of asynchronous motor soft starter by building a mathematical model of asynchronous motor equivalent circuit,because the soft starter designed in this thesis uses thyristor as the current limiting device,the principle of thyristor voltage regulation is analyzed in detail.As for the control algorithms,this thesis studies the PID control algorithm and the fuzzy control algorithm,then analyzes the advantages and disadvantages of the two algorithms,and finally uses a new fuzzy PID control algorithm that combines the two.At last,this thesis uses the Matlab/Simulink software to model and simulate soft start system based on PID control algorithm and soft start system based on fuzzy PID control algorithm,so as to verify the correctness and superiority of fuzzy PID control algorithm in soft start control of asynchronous motor.Based on the above theoretical analysis,this thesis designs the hardware system and the software system of the soft starter according to the principle of modular design.The hardware system design includes the STM32 minimum system,main circuit,synchronous detection circuit,trigger circuit,the voltage detection circuit,the current detection circuit,communication circuit and power supply circuit design.The software system design includes the design of the main program and related subprogram.In the end,this thesis conducts a physical test of the designed soft starter.The test results show that the soft starter designed in this thesis can effectively suppress the inrush current when the asynchronous motor start and realize the soft start of the asynchronous motor.