Research On Design And Control Strategy Of Parallel Medium Frequency Induction Heating Power Supply

Induction heating technology has the unique advantages of cleanliness,safety,high efficiency,and easy control.It gradually replaces traditional heating methods and is widely used in various fields such as machinery,petrochemical industry,and civil use.With the complexity and precision development of modern industrial production,higher performance is required for the performance of induction heating power supply.The improvement of its circuit topology and excellent control technology are the key to the efficient and stable operation of equipment.In recent years,the continuous development of digital chips has also created conditions for the improvement of the performance of induction heating power supply.Therefore,the research on induction heating power supply based on digital control is of great significance.First of all,this paper deeply analyzes the principle and topological structure of the induction heating power supply,and studies the theoretical basis of the induction heating power supply.By comparing the advantages and disadvantages of series/parallel inverters and the characteristics of series/parallel resonant loads,the parallel resonant induction heating power supply is selected as the research object,and the power modulation method of the parallel induction heating power supply is further compared and analyzed.The power is regulated by the Buck converter voltage regulation method.Thus,the overall topology of the system is determined.Secondly,the power control and frequency control of the induction heating power supply are studied.In the power control process,the buck circuit voltage and current double closed-loop control strategy is used.Based on the state space average modeling method and Matlab/Sisotool toolbox,the compensation network parameters are designed.The variable-speed integral PI algorithm is used to overcome the inflexibility in the traditional PI adjustment process.In the frequency control section,in order to ensure that the induction heating power supply always works in a resonant or quasi-resonant state,a phase-locked loop is used to track the resonant frequency of the inverter’s operating frequency and lock the voltage and current phases.The main circuit and control circuit models of the system were built on Matlab/Simulink platform for simulation verification.The simulation results show the correctness of the theoretical analysis and the feasibility of the control method.Finally,the software and hardware of the parallel induction heating power supply are designed,and the numerical control platform of the induction heating system with FPGA as the control core is built.Including the main circuit,drive circuit,sampling protection circuit,auxiliary power circuit and other hardware circuit design,and writing Verilog code in the Quartus Ⅱ development environment to realize part of the online simulation to ensure that the software design can meet the preset control requirements of system.Based on the built-up induction heating numerical control platform for experimental testing and analysis,the experimental results show that the induction heating power supply software and hardware design is correct and the control scheme is feasible.