Research On Control System Of High Power High Frequency And High Voltage Power Supply

With the development of science and technology,electron beam welding technology is developing towards high precision parts processing and automobile manufacturing.Although abroad research on high power electron beam welding machine are relatively mature,the domestic research is relatively backward,the lack of research on high power high frequency high voltage power supply control system,not related to the research on the characteristics and design of high power resonant converter and control loop.This paper introduces the development status and technical innovation of high power high frequency high voltage power supply at home and abroad,choose the LCC resonant converter as the main circuit topology of this subject,and determine digital control technology to achieve the system's closed-loop control.Further,based on the analysis of voltage gain characteristic,current transmission characteristics and resonator impedance characteristics of the high power LCC resonant converter,the paper puts forward the design scheme of high power LCC resonant converter.Through the Saber software simulation,verify the accuracy of the design parameters.By means of simulation waveform analysis,making it clearly that the traditional pulse width modulation(PWM)control strategy and frequency modulation(PFM)control strategy has the advantages and disadvantages of power supply control system of high power,put forward a hybrid control strategy of PFM combined with PWM.By means of equivalent circuit model and extended function modeling method,the small signal model of full bridge LCC resonant converter is derived,and giving the transfer function of current mode control loop.Based on the loop gain method,the balance of gain margin,phase margin and control bandwidth is achieved,and the linear PI closed loop controller is designed,which is based on the combination of PWM and PFM.Finally,the article detailed analysis of the design principle of hardware platform and software program of the power supply,and detailed analysis of the experimental results verify the high power LCC resonant converter and its closed-loop controller design is correct and feasible.