Study On Load Parameter Identification Of The Iduction Heating

Because of energy saving,environmental protection and high efficiency,induction heating technology has been widely used in various occasions,such as welding,smelting,casting and so on.Because of the complexity of the heating object,induction heating power supply is still faced with many challenges and is expected to develop towards a more efficient and greener direction.In induction heating,the heating coil and heating workpiece are equivalent to the form of inductance and resistance in series.Due to the shape and size of heating objects are different in different applications,so the load parameters are difficult to determine.In addition,during the heating process,the load parameters will change with the change of temperature,causing the change of the resonant frequency and heating power,which will affect the heating efficiency and effect.Especially,in smelting and other occasions,the load parameters will mutate at Curie point,which may lead to severe changes in the working state of the circuit,and damage the power supply.In view of the above situation,a load identification method of induction heating power supply based on recursive least-squares algorithm with variable forgetting factor is given in this paper,the corresponding power and harmonic frequency are determined by identificating load parameters to achieve the purpose of efficient heating.Especially when the load is abrupt,the algorithm can calculate quickly and accurately,and make the circuit run safely and stably.According to the load characteristics and requirements of the induction heating power supply,the equation model of the load channel of the induction heating power supply is set up.The relationship between the inductance and the resistance of the load and the voltage of the load and the channel current is listed.The equation is solved by the recursive least square method with variable forgetting factor,and the inductance and the resistance of the load are finally calculated.The power source can be heated efficiently by adjusting the frequency and power.In order to realize the accurate identification of load inductance and resistance mutation,the forgetting factor is added to adjust and realize fast identification,so as to ensure the stable operation of the power supply.It is proved that this method can effectively solve the problem of load parameter changes caused by the simulation and establishing the experiment platform of induction heating based on ARM and FPGA.