High-frequency heating apparatus

A high-frequency heating apparatus comprising:

• a first electrode;
• a second electrode disposed facing the first electrode;
• a high-frequency power supply configured to supply a high-frequency power to the first electrode;
• a position adjuster configured to adjust a distance between the first electrode and the second electrode;
• a detector detecting a reflected power from the first electrode toward the high-frequency power supply and an incident power from the high-frequency power supply towards the first electrode;
• and
• a controller configured to control the position adjuster based on the reflected power and the incident power,
• wherein the position adjuster moves one or both of the first electrode and the second electrode, and
• wherein the controller is further configured to:
• cause the position adjuster to adjust the distance between the first electrode and the second electrode;
• determine the adjusted distance based on a change of capacitance before and after the distance between the first electrode and the second electrode is adjusted;
• acquire values of the reflected power and the incident power from the detector at the adjusted distance;
• calculate a reflection rate based on the values of the reflected power and the incident power;
• determine that a heating target is not placed between the first electrode and the second electrode, when both the calculated reflection rate is greater than a first threshold value and the adjusted distance between the first electrode and the second electrode is equal to or less than a predetermined second threshold value;
• and
• determine that the heating target is placed between the first electrode and the second electrode, when both the calculated reflection rate is less than or equal to the first threshold value and the adjusted distance between the first electrode and the second electrode is greater than the second threshold value.