Research And Design Of Electromagnetic Induction Heating Power Used In Injection Machine

After entering the 21st century,Induction heating technology has developed rapidly.In recent years,induction heating power supplies have been widely used in plastic manufacturing,small and medium-sized power supplies have been widely used in injection molding heating of injection machines.However,from the current situation,the performance and control methods of induction heating power supplies for injection molding heating in the market are uneven.Most power supplies have disadvantages such as large energy consumption and poor stability due to different applications.In response to this situation,this thesis analyzes the principle,technical specifications and actual needs of the induction heating of the injection machine.Taking the injection machine barrel of SCM440 steel as the research object,designed a 2.5kW/20kHz induction heating power supply for heating hot melt plastics such as PVC.Firstly,for the main circuit structure of the power supply,this thesis chooses the main circuit topology structure of uncontrolled rectification,DC chopping and full-bridge series resonant inverter circuit,the design of the main circuit parameters and the selection of components are completed.Secondly,regarding the control strategy of the power system,this thesis aims at the disadvantages of the complexity of inverter-side power regulation and the difficulty of cooperating with frequency tracking control,it adopts a DC chopping power modulation method that is simpler in control and has no effect on the load side.Aiming at the defect of the sudden change of load parameters during the injection molding heating process and the defects of the traditional analog phase-locked chip,using TMS320F28335 chip to design digital phase lock.Completed the tracking of the operating frequency of the inverter circuit to the load resonance frequency and it make the power system work in the partial inductive quasi-resonant state all the time,reduce the loss.In addition,this thesis aims at the nonlinear characteristics of the injection molding machine barrel temperature.In the past temperature PID control,fuzzy control is added to make the barrel temperature control more accurate.For the designed main circuit parameters and system control strategy,this thesis uses Simulink for modeling and simulation.The simulation results show that the designed circuit structure and control strategy are feasible and effective.Based on research and analysis,the thesis designs the hardware and software of the power supply system,and makes the power supply prototype.An experimental platform is built for experimental testing.The test results show that the main circuit of the power supply designed in this thesis is reasonable and the control strategy formulated is effective,which has certain value for practical application.