Defrosting apparatus with arc detection and methods of operation thereof

A thermal increase system comprising:

• a radio frequency (RF) signal source configured to supply an RF signal;
• an electrode coupled to the RF signal source;
• a transmission path electrically coupled between the RF signal source and the electrode;
• a variable impedance network that is coupled along the transmission path between the RF signal source and the electrode;
• and
• a controller configured to detect electrical arcing occurring along the transmission path based on at least a rate of change of a parameter of the RF signal, and to modify an operation of the system in response to detecting the electrical arcing.

A method of operating a thermal increase system that includes a cavity, the method comprising:

• supplying, by a radio frequency (RF) signal source, one or more RF signals to a transmission path that is electrically coupled between the RF signal source and one or more electrodes that are positioned proximate to the cavity;
• periodically measuring, by measurement circuitry, a parameter of the RF signal along the transmission path, resulting in a plurality of parameter measurements;
• determining, by the controller, a rate of change of the parameter based on the plurality of parameter measurements;
• determining, by the controller, that the determined rate of change exceeds a predefined threshold;
• and
• modifying, by the controller, operation of the thermal increase system in response to the determined rate of change exceeding the predefined threshold.