Research And Design Of Super-Audio Frequency Induction Heating Power Supply

With the development of environmental protection economy and green economy,the industrialization road has gradually developed towards the directions of energy conservation,high efficiency and environmental protection,which also has also promoted the development of induction heating technology.Although the domestic super audio induction heating technology has developed rapidly,it still needs to be improved in terms of digitization,circuit structure,and capacity.Therefore,in this paper,a field programmable gate array(FPGA)is used as the main control chip to research the digital control of the super audio induction heating power supply.First of all,takes the super audio induction heating power supply as the research object,analyzes and compares the series-parallel load resonance circuit,selects the series resonance circuit as the research object,and the main circuit adopts a three-phase uncontrolled rectification and a single-phase full-bridge inverter topology.Analyze and compare the advantages and disadvantages of different power modulation methods on the DC side and the inverter side.Pulse phase shift power modulation on the inverter side is adopted.The working state of the pulse phase shift power modulation method in the capacitive state is analyzed in detail.To cope with the frequent start of series resonance induction heating power and the sudden change of the equivalent load of the load resonance circuit,the combination of closed loop control strategy with a frequency inner loop and a power outer loop was selected.In order to overcome the shortcomings of the traditional PI adjustment algorithm,a variable parameter and integral separation type PI adjustment algorithm is used to improve the system's rapidity.With calculating and analyzing the various indicators of the super audio induction heating power system,the phase-locked loop module and the phase shifting modulator block are stimulated by using Matlab/Simulink software analysis.When compared with the Digital PI separation adjustment algorithm,the variable parameter and integral separation type PI adjustment algorithm reduces the overshoot,improves the dynamic response,and enhance the stability.As the result,Simulation results verify the feasibility of the control strategy.Finally,completes the design of FPGA peripheral,driving,sampling and protection circuits.Using an experimental hardware in the laboratory,the software program based on Quartus II was written,and various output waveforms were obtained.The experimental results show that the all-digital phase-locked-loop can quickly track the change of load frequency;the power is continuously adjustable;and the overcurrent and overvoltage fault protection is accurate.The result further demonstrates the correctness and feasibility of the control scheme in this paper.