Research On Electromagnetic And Thermal Problems Of Intermediate Frequency Induction Heating Integrated Machine

As the scale of domestic wind power and photovoltaic power grows,the problem of wind and solar abandonment caused by these clean energy cannot be absorbed or stored in time is becoming more and more serious.As one of the ways to realize energy storage,the electromagnetic thermal energy storage system assumes the role of alleviating the abandonment of wind and light,promoting the absorption of new energy and shifting peaks and valleys.Applying it to the deployment of grid energy has now become a domestic research hotspot.At present,induction heating control power supplies are developing in the direction of high frequency and high power.In order to match the use of induction heating loads with the development of control power supplies,it is necessary to study their electromagnetic and thermal issues.This topic takes the 12 k Hz/50 k W intermediate frequency induction heating integrated machine as the research object,adopts formula analysis calculation,software finite element analysis and simulation and the method of setting control group analysis to study the electromagnetic and thermal problems of the intermediate frequency induction heating integrated machine.The research work is as follows:Combined with the theoretical knowledge of induction heating,the three working states of the load side of the induction heating device are analyzed,and it is clear that the load working in a weakly inductive state can make the device work with the highest reliability.Using software to simulate the working process of the induction heating circuit,the voltage and current under different capacitance and inductance matching are obtained.Afterwards,the main losses in the induction heating power supply are calculated,which will be used as the basis for calculating the temperature field of the induction heating power supply.Electromagnetic analysis is carried out on the load of the all-in-one machine.Taking it as a quasi-static field problem,a mathematical model is established,the field and boundary equations of the steel pipe,air and winding parts are given,and the electromagnetic potential of the air and the electromagnetic power expression of the steel pipe are derived.Later,the software was used to perform finite element analysis on the heating load.Finally,it was found that changing the number of winding turns is the most effective way to adjust the load without changing the nature of the load’s working state.It is clear that the control power supply of the all-in-one machine mainly transfers heat to the outside in three ways: conduction,convection and radiation,and the heating load mainly transfers heat in two ways: conduction and convection.Aiming at the thermal problems of the control power supply and the induction heating load,two sets of schemes were designed respectively,and the finite element analysis of these schemes was carried out with software.Through the analysis of the calculation results,the best design plan for controlling the heat dissipation of the power supply and the heat transfer of the load structure is obtained.Finally,an intermediate frequency induction heating integrated machine experimental platform was built,and the heating experiment was carried out.During the period,the voltage and current waveforms at both ends of the load are obtained,which are the same as the previous simulation results;the windings on the outside of the load and the temperature of the inlet and outlet water are also monitored,which is corroborated with the simulation results.The experiment shows that the electrothermal conversion efficiency of the integrated machine is about 90 %.