A Novel Digital Control Algorithm for a DC-DC Converter in Plasma Application

This paper presents a novel digital control algorithm to enhance the dynamic performance of a dc-dc converter for non-high-frequency arc (NHFA) plasma cutting power supply. Using the principle of capacitor charge balance, the proposed algorithm predicts the optimal transient for a dc-dc converter during a load change. A 16kW experimental prototype of the NHFA plasma cutting power supply is designed and relevant experiments are carried out to verify the method. Theoretical analysis and experimental results show that the optimal transient performances, including the smallest output current undershoot and the shortest recovery time, are achieved by using the proposed algorithm. And the successful ratio of plasma arc ignition and the quality of the cutting are improved obviously.