The present invention provides a power feedback control system for controllably maintaining a predetermined average power value of a power applied to a plasma of a sterilization system. The power has a frequency of from 0 to approximately 200 kHz. The power feedback control system includes a power monitor including a current monitor and a voltage monitor. The current monitor is adapted to produce a first signal indicative of a current applied to the plasma. The voltage monitor is adapted to produce a second signal indicative of a voltage applied to the plasma. The power monitor is adapted to produce a third signal in response to the first signal and second signal. The third signal is indicative of the power applied to the plasma. The power feedback control system further includes a power control module adapted to produce a fourth signal in response to the third signal from the power monitor and to a reference signal corresponding to the predetermined average power value. The power feedback control system further includes a power controller adapted to adjust, in response to the fourth signal, the power applied to the plasma to maintain the predetermined average power value of the power applied to the plasma.