The sliding mode control for arc welding inverter power source

In order to overcome the contradictory between the small voltage overshoot and the fast response time of the traditional PI control, sliding mode control (SMC) is introduced on the basis of using TMS320LF2407 into the pure digital control system of phase-shift full-bridge ZVS arc welding inverter power source. This has not only effectively solved the voltage overshoot during the welding process, but also realized a faster voltage response. In this paper, phase-shift full-bridge indirect SMC is adopted, then the control algorithms based on the average state space model is deuced theoretically, and in addition, a new phase-shift PWM wave generation method is applied which makes the control more practical and simpler, and finally a 20 kW arc welding power source is developed on which the experiment results prove the effectiveness of control algorithm through the experimental comparing between SMC and PI control.