Small-signal modeling for peak current mode PSFB-ZVS PWM arc-welding inverter and control loop design

For the development of a digitalized 20 kW/50 kHz pulsed MIG/MAG arc-welding inverter, the Peak current mode PSFB-ZVS PWM converter topology is used to improve the accuracy and dynamic response of the control system. Thesmall-Signal model for power stage of PSFB-ZVS PWM in CCM is derived using the averaged switch modeling approach.A complete small-signal model of the peak current mode PSFB-ZVS PWM arc-welding inverter is derived based on the derivation of the small-signal model for peak current mode control stage. The design principle of slope compensation is derived. A PI frequency compensator is designed. The analytical result of small-signal model is accord with the frequency response through the frequency domain simulation using Simplis software.