Research And Design Of Medium Frequency Induction Heating Power Supply

This paper takes the medium frequency induction heating power as the research object,starting with the principle of induction heating,compares and analyzes the advantages and disadvantages of the series and parallel resonant load,then chooses the more advantageous series resonant medium frequency power supply as the research object.Through the analysis and research of the main circuit of the power supply,three phase uncontrolled rectifier and single-phase full bridge inverter topology are selected.First of all,aiming at the mismatch between power regulation mode and power device in induction heating power supply,this paper analyzes several power regulation modes on DC side and inverter side,aiming at the characteristics of high-power power electronic device(IGBT),adopts the inverter lateral shift PWM control mode as voltage regulation choice.The main circuit parameters are calculated by analyzing the working waveform of elements of inverter phase-shifted voltage gate.Because the series resonant power supply is more suitable to start up frequently and the traditional PI regulation is not fit to the fast steady state of the system,the PI separation adjustment algorithm is studied emphatically to apply to the intermediate frequency induction heating power supply in order to improve the system’s fast adjusting performance.Using Matlab/Simulink build the power supply simulation system,and the simulation results verify the feasibility and correctness of the control mode.Secondly,aiming at the problem that the digital signal processing is cumbersome in capacitive phase-shifting and power modulation mode and the traditional phase-locked loop is easy to cause over-harmonic saturation,established a digital control system and current zero-crossing synchronization technology based on TMS320F28335 DSP chip.Finally,the drive circuit,voltage and current detection circuit and protection circuit are designed.The system software was designed and the experimental platform was built,and the related experiments were verified.The correlation waveform obtained from the experiment is compared with the simulation waveform,and the results are consistent,which further verifies the correctness and feasibility of the theoretical analysis and the design of the system.