Half-bridge Series Resonant Induction Heating Power Supply Design

With the consumption upgrading and cooking reforming,the market requires of induction cooker is getting higher and higher,customers require a fire cooking experience when using induction cooker,such as the characteristics of large-level firepower,low-level continuous firepower,and the high-frequency control core.But all the existing induction cooker are facing the problems of high power consumption in standby and low efficiency of power transfer in low-level continuous using.Therefore,it is necessary to develop a new induction with a wide range of continuous output firepower,high transfer efficiency,rapid loading change protection,high power density and low electromagnetic interference.This paper chose a resonant induction heating half-bridge inverter for variable frequency control.According to the performance indicators of wide range continuous output power,the parameters of main electron device was set;the auxiliary power system was redesigned;improvement of circuit design was made for lowing down standby power consumption;induction heating coil plate was redesigned and improved;digital phase-locked loop control core of the limit of phase was redesigned;phase limit of phase lock loop software and power control software are redesigned;the main circuit state was analyzed.This paper analyzed the working process of main circuit with auxiliary buffer capacitor and relay diode;chose the frequency conversion control method which can smoothly adjust the output power;the calculating method of neutral zone(for reducing the wastage of buffer capacitor in switching and for ensuring the reliable operation of the system)was obtained by formula derivation.This paper analyzed the wastage of device on the resonant half-bridge inverter.Based on the model of switching device on thermal simulation model,the PLECS software was used for establishing simulation model of system efficiency and power closed-loop control,the frequency switching,resonant capacitor changing and constant power parameters are simulated,this paper summarized the above things to improve the efficiency of whole system and applied on the design of developing induction cooker.By developing a 3k W resonant half-bridge inverter,we tested the efficiency improvement scheme of the induction cooker,collected and analyzed the main data of waveform and thermal efficiency.The result show that the method is effective.