Research On Load Adaptability Of Induction Heating Cooker

Due to the rapid,efficient,safe and other advantages,induction heating(IH)cooker has become an indispensable household appliance.Traditional induction heating has been developed to effectively heat a ferromagnetic pan or special cookers for induction cookers,but IH cooker is incapable of heating a non-ferromagnetic pan.In addition,the use of induction cookers of different brands has common problems,so the induction cooker has poor adaptability to different permeability cookers.Therefore,it is of great significance to improve the versatility and wide use of the induction cooker to adapt to the heating of various metal cookware.According to the principle of electromagnetic induction heating,when the system parameters are determined,in order to achieve heating of non-ferromagnetic pan,it is necessary to increase the load resonance frequency and increase the load equivalent impedance.Therefore,this paper describes a scheme that uses the relay coil structure to improve the load adaptability,making the induction cooker suitable for heating pots of various materials.The presence of the relay coil can also reduce the switching tube current.In this scheme,the inverter circuit has four working modes,which not only makes the output power meet the requirements,but also minimizes the coil current.In this paper,the small signal analysis method is used to derive the equivalent impedance expression of the induction cooker system,and the relationship between the equivalent resistance and equivalent inductance of the induction cooker system and the frequency when the magnetic permeability and resistivity of the cookware changes is analyzed.According to the requirements of system output power and load adaptability,the working mode of the inverter circuit in this scheme is analyzed,the mode selection method is designed,and the impedance characteristics and coil current characteristics of the relay coil structure are studied.The COMSOL software was used to conduct thermal simulation of cookers with different permeability for electromagnetic induction systems using relay coils and without relay coils.It was verified that the use of relay coils has better adaptability to cookware.Finally,the feasibility and correctness of the scheme are verified by PSIM circuit model simulation and low-power experimental platform.