Abstract: Provided is a plasma generating system including: a resonant inverter including a switching circuit and configured to generate a device output current and a device output voltage, and to have a switching frequency based on an input DC current and an input DC voltage; a plasma source configured to generate a plasma based on the device output current and the device output voltage; a controller configured to control the switching frequency of the resonant inverter based on a value of the input DC current, a value of the input DC voltage, a value of the device output current, and a value of the device output voltage; and a junction temperature estimator configured to: estimate a current output from the switching circuit based on the value of the input DC voltage, the value of the device output current, and the value of the device output voltage, generate an inverted current estimate value, and estimate a junction temperature of the switching circuit based on the inverted current estimate value.