Research On Uniform Electromagnetic Heating Control System

As the country attaches great importance to environmental protection,traditional paint panels are gradually replaced by thin-plate heating films.Electromagnetic induction heating technology has outstanding advantages,such as environmental protection,high efficiency and energy saving,which make it replace traditional heating methods in this field gradually.But in the process of electromagnetic induction heating,due to the uneven distribution of the induced eddy currents in the thin plate,it will affect filming quality.In order to solve the problem of uneven temperature of the sheet metal during induction heating,a multi-coil combined induction heating control system is proposed in this paper and the following research is carried out:Firstly,analyze the topology structure,advantages and disadvantages of series resonant circuit and parallel resonant circuit,and the series resonant circuit is selected as the induction heating power inverter circuit,moreover,the load characteristics and parameters are analyzed and calculated.Analyze the SPWM sinusoidal pulse width modulation technique and use it as the inverter circuit drive signal.At the same time,the ratio control method is applied to the temperature control system.Select the coil near the center of the sheet metal as the main coil,other coils form a closed loop servo system according to the settings to make the temperature adjust automatically between the coils to achieve the goal of uniform heating.Hardware design is carried out for the whole system in order to control the combined heating coil more precisely by taking DSP,whose model is TMS320F28335,as the core.The hardware of IGBT and its driving module,signal acquisition circuit,temperature acquisition module and protection circuit are analyzed and designed to meet the stability and control requirements of the system operation.Software design is carried out for the whole system.It mainly includes the main program design of the control system.Parameter setting and algorithm implementation of SPWM on DSP.Subroutine design of sampling module,including current and voltage acquisition process and temperature acquisition process.In order to improve the uniformity of heating,optimize the ratio controller to improve the efficiency of the temperature adjustment between coils.Finally,build the uniform induction heating experimental platform and conduct comparative experiments.The experimental results show that the system can effectively improve the uniformity of the temperature of sheet metal in the induction heating process,and meets the design requirements and has a high application value.