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A Novel MCIs Dual-Bridge for Plasma cutting power supply with Arc Current Feedforward Compensated Phase-Shift Control

This paper presents a novel multi-stage coupled inductors (MCIs) dual-bridge converter using phase-shifted control strategy with arc current feedforward compensated, aiming to meet the demands of low frequency arc ignition, arc transfer process and multi-mode cutting in plasma cutting power supply. Compared to the conventional half-bridge and full-bridge converters, the proposed (MCIs) dual-bridge converter can suppress the output current ripple greatly, which benefits from inductance coupling and double control frequency. Then, the mathematical model of multi-stage coupled dual-bridge is built, and the phase-shifted control method is studied. Combined with the advantages of (MCIs) dual-bridge converter, the proposed control algorithm with arc current feedforward can solve the arc problems of ignition failure via plasma arc current compensation and pneumatic circuit compensation, which caused by serious current fluctuation during sudden change of air pressure and arc transform frequently in cutting process. To verify the feasibility of the proposed multi-stage coupled dual-bridge converter and control scheme, a 20kW experimental prototype for plasma cutting power supply has been built. The experimental results show that the proposed topology and control scheme help to improve the success rate of arc ignition, reduce the probability of cutting arc breaking, make the power supply more stable and the cutting effect much better.