The sliding mode control for air plasma cutting inverter power source

According to the basic characteristics of air plasma cutting inverter, the cutting inverter with sliding mode control (SMC) is researched and designed. Unlike the traditional PI control with the contradictory between the small voltage overshoot and the fast response time, SMC has not only effectively solved the voltage overshoot during the cutting process, but also realized a faster voltage response. In this paper, Phase-Shift Full-Bridge (PSFB) indirect SMC is adopted. The control algorithms based on the average state space model is deuced theoretically, and a new phase-shift PWM wave generation method is applied which makes the control simpler. Finally a 10kW cutting inverter power source is developed, and experiment results prove the validity of the control algorithm.