Waveform detection of states and faults in plasma inverters

A system for determining an operational state of an atmospheric pressure plasma, the system comprising:

• a transformer for coupling power into the atmospheric pressure plasma, wherein the transformer comprises a ballast transformer having a magnetic core, a primary winding on a primary side of the magnetic core, a secondary winding on a secondary side of the magnetic core, and wherein the primary winding is connectable to a power source, and the secondary winding is connectable to a plasma load of the atmospheric pressure plasma;
• a current sampling circuit configured to sample at least one current pulse flowing through a primary winding of the transformer;
• and
• a programmed microprocessor configured to determine, from a waveform of the current pulse, the operational state of the atmospheric pressure plasma,
• wherein the operational state comprises one of
• a no plasma state,
• a plasma origination state indicative of an ignited arc expanding into a larger plasma volume by gas flow thereinto, and
• a plasma maintenance state indicative of the plasma being expanded into the desired volume and steady-state condition.