Electronically Controlled Mechanical Timepiece, Control Method Of An Electronically Controlled Mechanical Timepiece, And Electronic Timepiece

An electronically controlled mechanical timepiece comprising:

• a mechanical energy source;
• a generator including a rotor driven by the mechanical energy source;
• a power supply circuit configured to store electrical energy generated by the generator;
• an energy transfer mechanism configured to transfer torque from the mechanical energy source to the rotor;
• a time display device connected to the energy transfer mechanism and configured to display time;
• a crystal oscillator;
• and
• a rotation controller configured to control rotation of the rotor and including:
• an oscillation circuit that causes the crystal oscillator to oscillate,
• a frequency divider that frequency divides an oscillation signal output from the oscillation circuit and outputs a reference signal,
• a temperature compensator including a temperature detector measuring temperature and configured to compensate for a frequency of the reference signal based on the temperature measured by the temperature detector,
• a rotation detection circuit configured to measure the rotational frequency of the rotor, and
• a brake control circuit configured to control braking of the rotor according to a difference between the rotational frequency of the rotor and the frequency of the reference signal compensated by the temperature compensator.