Characterization of a Compact, Low-Cost Atmospheric-Pressure Plasma Jet Driven by a Piezoelectric Transformer

To realize the broadest potential of nonthermal atmospheric-pressure plasma (APP) technology, there is a need to develop low-cost, compact devices that can be used for portable applications. One of the greatest impediments to this is the power supplies and/or electronics needed to generate breakdown at atmospheric pressure. Piezoelectric transformers (PTs) are solid-state transformers that can produce large gains in voltage, which along with their modest size, makes them attractive candidates for use in plasma production. In this paper, we use a low-voltage power supply in line with a PT to produce an APP jet (APPJ). While operating at the resonance frequency of the PT (88 kHz), plasma jets were generated with input voltages as low as 10 V. The electrical and optical characteristics of the piezoelectric-driven jet were compared to an APPJ produced with a high-voltage sine wave of comparable operating frequency. Both APPJs were examined in helium and argon for a variety of different flow rates and operating voltages. In argon, the length of the jets was nearly identical for all operating parameters but produced different discharge currents. In helium, the discharge currents were similar but the lengths of the jet differed. Optical emission spectroscopy showed similar chemical composition between the two jets for both feed gases. Together, the results suggest that the piezoelectric material has an influence beyond simply amplifying voltage but can be successfully integrated to meet the requirements needed for plasma production.