Vibration damping system and elevator apparatus

A vibration damping system comprising:

• a displacement amplifier arranged along a given position in a longitudinal direction of an elevator rope, the displacement amplifier being configured to amplify a displacement due to vibration of the elevator rope when the displacement amplifier is in a first state, and not amplify the displacement due to vibration of the elevator rope when the displacement amplifier is in a second state;
• and
• processing circuitry
• to calculate a natural frequency of the elevator rope;
• and
• to switch a state of the displacement amplifier based on the natural frequency calculated and a preset vibration frequency,
• wherein:
• the processing circuitry calculates as a first natural frequency the natural frequency of the elevator rope when the displacement amplifier is in the first state, and
• the processing circuitry switches the state of the displacement amplifier to the second state when the first natural frequency is included in a limited range that includes the preset vibration frequency.

A vibration damping system comprising:

• a displacement amplifier arranged along a given position in a longitudinal direction of an elevator rope, the displacement amplifier being configured to amplify the displacement due to vibration of the elevator rope based on a variable amplification factor;
• and
• processing circuitry
• to calculate a natural frequency of the elevator rope;
• and
• to change the amplification factor of the displacement amplifier based on the natural frequency calculated and a preset vibration frequency.