Motor-generator, power generation apparatus, and mobility device

A motor-generator configured to use no flywheel connection to an internal combustion engine, the motor-generator comprising:

• an inner stator;
• and
• an outer rotor arranged to surround the inner stator, the outer rotor being connected to the internal combustion engine without a flywheel, the outer rotor serving as an alternative to the flywheel and being configured to reduce noise due to at least one of torque ripples of the internal combustion engine and rotational fluctuations of the motor-generator, wherein
• the outer rotor has inertia serving as inertia moment thereof,
• the internal combustion engine includes a shaft, and
• when the shaft outputs torque having ripples that exceed 200 Nm, the inertia of the outer rotor, being greater than or equal to 0.1 kg·m2, maintains rotational fluctuations of the motor generator at or below 200 rpm peak-to-peak.