High-frequency power device and method for controlling high-frequency power

A high-frequency power device comprising:

• an oscillator, adapted to output an oscillation signal and vary an oscillation frequency of the oscillation signal in accordance with an instruction;
• a high-frequency power supplier, adapted to amplify the oscillation signal to supply high-frequency power to a load capable of discharging;
• a reflection coefficient calculator, adapted to calculate an absolute value of a reflection coefficient based on information of high-frequency oriented from the high-frequency power supplier toward a side of the load and high-frequency oriented from the side toward the high-frequency power supplier and output the calculated absolute value to a frequency controller;
• a discharge signal output unit, adapted to output a discharge signal to the frequency controller to change the oscillation frequency before and after the load discharges;
• and
• the frequency controller, adapted to give the instruction to the oscillator based on the absolute value and the discharge signal, wherein
• the frequency controller:
• instructs the oscillator to oscillate the oscillation signal at a first oscillation frequency for the period of time while the discharge signal is not in a state showing that the discharge has been commenced or in a state where the discharge is regarded as having been commenced, then
• instructs the oscillator to change the first oscillation frequency to a second oscillation frequency immediately after the discharge signal changes into the states, and then
• controls the oscillation frequency so that the absolute value is made small.