Research On The Special Drive System Of Injection Molding Machine Based On Model Predictive Control

The promotion of the "Industry 4.0" strategy of Germany indicates that modern industry has entered a new stage of development-smart manufacturing.The State Council promulgated "Made in China 2025" to fully promote the healthy and rapid development of China's manufacturing industry,reaching the world's advanced level.Injection molding manufacturing is an important part of China's manufacturing industry.At present,the key technical indicators such as control precision,robustness,and system energy consumption of domestic injection molding machines are far from those in foreign countries,and most of the overseas brand occupyers are in the high-end market.This project is based on the injection molding machine system of permanent magnet synchronous motor(PMSM)and aims to improve its system efficiency and reliability.Firstly,this paper analyzes the components and working principle of the injection molding machine dedicated drive system,and deeply studies the relationship between permanent magnet synchronous motor torque speed and the pressure flow control of the injection molding machine drive system.Secondly,the composition and working principle of permanent magnet synchronous motor were analyzed,and its mathematical model and vector control strategy were deeply studied.The vector control method of d-axis current input zero((9= 0)of permanent magnet synchronous motor was analyzed.Considering the requirements of the dynamics and efficiency of the injection molding machine,taking into account the problem of parameter problems and low response speeds caused by the cascaded proportional-integral(PI)architecture of vector control,the subject has studied the model predictive control(MPC)theory,a system velocity loop model prediction controller and a single control loop model prediction controller are designed.The speed loop model predictive controller uses the discretized motor dynamic equation as a prediction model.The difference between the predicted speed and the actual speed is the error correction amount,and the current control increment is obtained through the optimal solution of the quadratic performance index function.The single control loop model predictive controller is based on the velocity loop model predictive controller,and the spatial state equation of the permanent magnet synchronous motor in the dq coordinate system is designed as a predictive model based on the second-order model relationship of voltage and rotation speed to predict and actualize.The difference between the rotational speeds is the error correction amount,and the optimal control rate,ie,the voltage increment,is designed through the performance index function.Finally,the system was modeled and simulated by Matlab/Simulink software,which proved the feasibility of the algorithm.The topic is to design the hardware control system based on TI's TMS320F28335 motor control microprocessor,which includes the control circuit and the power circuit,and design the driving algorithm of each module,mainly including the sensor sampling module,rotor positioning algorithm,speed estimation and space vector pulse width modulation(SVPWM)algorithm.The experimental results show that the permanent magnet synchronous motor system based on model predictive control has faster response and higher efficiency,and it can well meet the key performance indicators of high-performance injection molding machines.