Hybrid power driving system and gear position operation method thereof

A hybrid power driving system for a vehicle, comprising:

• an internal-combustion engine;
• a first electric motor;
• a second electric motor;
• a planetary coupling mechanism;
• a speed-reduction mechanism;
• and
• a differential mechanism;
• wherein an output shaft of the internal-combustion engine is connected directly with an input shaft of the first electric motor;
• an output shaft of the first electric motor is connected with an output shaft of the second electric motor via a first clutch;
• the output shaft of the second electric motor is connected with one of a sun gear and a ring gear of the planetary coupling mechanism at a first position of the output shaft of the second electric motor along the axial direction of the output shaft of the second electric motor;
• and the output shaft of the second electric motor is connected with the other one of the sun gear and the ring gear at another position of the output shaft of the second electric motor along the axial direction of the output shaft of the second electric motor via a second clutch;
• a planet carrier of the planetary coupling mechanism is connected to an input gear of the speed-reduction mechanism;
• and an output gear of the speed-reduction mechanism is connected to a shell of the differential mechanism.