Research And Design Of Power Supply And Control System For High-Power Electric Cooker

With the vigorous development of green and low-carbon energy economy in our country,all-electric kitchen utensils have been vigorously promoted,and electric cookers have become the main force of the family kitchens.Compared with the traditional cookers,the core induction heating technology has the characteristics of energy saving,high efficiency and safety,which greatly facilitates people’s daily life and is favored by consumers.However,as the low power electric cookers can not meet the commercial demand,they are less popular in modern catering industry,so the electric cookers are developing towards the direction of high power,high efficiency and intelligence.In this thesis,the power supply and control system of high-power electric cookers are taken as research and analysis objects,aiming at the problem that the single pulse frequency power adjustment of high-power electric cookers have large loss and weak power modulation ability in low load and high frequency band,a hybrid power control strategy combining Pulse Frequency Modulation and Phase Shift Pulse Width Modulation(PFM-PSPWM)is adopted for full-bridge series resonant inverters,the feasibility of this strategy is verified by simulation platform.Firstly,based on the research background and current situation,this thesis introduces the working principle and characteristics of high-power induction heating electric cooker system,the main circuit module is designed by comparing different topologies;analyses the power regulation modes as well as applicable scenarios of the DC side and the inverter side of the system,and selects the PFM-PSPWM mixed mode to complete the power regulation.Secondly,by analyzing the operating state of the two power regulation modes,the power function relationship and loss characteristic model are established,it is shown that the output efficiency of PFM strategy is low in the high frequency band,and the advantages of the hybrid power modulation strategy.This strategy is proposed to use PFM strategy mode in low frequency band to achieve high power and high efficiency output,and switch to PSPWM mode at constant frequency in small and medium power segment to reduce the loss of the system at high frequency.At the same time,the phase-locked loop circuit of the heating power supply of the electric cooker is designed to track of the working frequency to the resonant frequency of the load;in the temperature control strategy,fuzzy PI control is used to reduce the steady-state error and achieve accurate control.Finally,hardware circuits such as power supply circuit,sampling protection,phase-locked loop and IGBT driver are designed and relevant DSP programs are written;at the same time,the simulation model of 20kW high-power electric cooker control system is built in the MATLAB/Simulink environment to verify the power regulation ability under different power regulation modes,and the current closed-loop control frequency switching mode is adopted to achieve power regulation;and the rationality of the simulation results is analyzed.