Development of DC Power Supply for Plasma Activated Water Using Gliding Arc Discharge

This article describes a design of dc power supply (DCPS) for a gliding arc discharge (GAD) for plasma-activated water (PAW) production. The GAD reactor requires both high- and low-voltage condition depending on the existence of plasma. This dynamic load characteristic depends on airflow and discharge current conditions. Therefore, the design of DCPS less susceptible to the dynamic load condition is necessary. As a topology for stable current supply, discontinuous conduction mode series resonant converter (DCMSRC) is applied. Owing to zero current switching (ZCS) characteristic, DCMSRC can operate with high switching frequency. The output current is proportional to the operating frequency regardless of the load resistance. This feature contributes to removing a ballast resistor, which is used to maintain unstable arc current. The designs of resonant parameters with explanation of operating principle are introduced. An additional analysis considering parasitic resonant capacitor caused by transformer (TX) and output rectifier circuit is described for predicting the ZCS region. Using the developed DCPS, experiments with a resistor load and the GAD reactor are carried out. Experimental results under various airflow and discharge current conditions are introduced. Finally, the maximum efficiency of the PAW production is achieved as 500 L/kWh.