Method of and apparatus for controlling molten metal surface in mold of continuous-casting machine and continuous-casting machine including the apparatus

A method of controlling a molten metal surface level in a mold of a continuous-casting machine, the method comprising:

• performing oscillation of the mold by using at least one of a hydraulic cylinder and an electrically-driven cylinder;
• and
• controlling the oscillation of the mold by:
• measuring a molten metal surface level in the mold;
• generating a composite control signal by correcting a reference waveform signal of a predetermined amplitude and a predetermined period for the oscillation of the mold, based on a difference between a measured value of the molten metal surface level and a desired value of the molten metal surface level;
• and
• changing a reference position of the oscillation of the mold by operating at least one of the hydraulic cylinder and the electrically-driven cylinder according to the composite control signal to prevent a relative position between the mold and the molten metal surface level from varying to maintain an initial solidification state.