Motive power system, transportation apparatus, and power transmission method

A motive power system comprising:

• a first energy storage having a first power density and a first energy density;
• a second energy storage having a second power density higher than the first power density, and a second energy density lower than the first energy density;
• an actuator to provide motive force to a load with electric power supplied from at least one of the first energy storage and the second energy storage;
• an internal combustion engine to provide motive force to the load;
• a power transmission circuit via which the actuator is connected to the first energy storage and to the second energy storage to supply electric power to the actuator;
• and
• circuitry configured to
• control the power transmission circuit and the internal combustion engine such that only the actuator provides motive force to the load in a charge-depleting mode and such that the internal combustion engine and the actuator provide motive force to the load in a charge-sustaining mode;
• and
• control the power transmission circuit in the charge-depleting mode such that the first energy storage supplies to the actuator a first electric energy that is stored in the first energy storage with a first charge rate range and the second energy storage supplies to the actuator a second electric energy that is stored in the second energy storage with a second charge rate range, the first charge rate range being larger than the second charge rate range.