The invention relates to a mixed power system and its power control method. The system comprises a motor (combustion engine), a speed changer, a energy storage device, a brake device, a motor controller, and a power system controller. Wherein, the speed changer is a power division system formed by a power transmission device and a power adjust device to utilize part divided power to adjust the speed and the torque of power system output. The power division system can at least supply one working condition of composite power division. The power system controller can adjust the output power of motor, the energy transmission of energy storage device and the braking power of brake device according to the system working condition and set the motor working condition (torque and rotational speed). The system controller can realize the control of motor rotational speed by setting and controlling the motor working torque according to the error signal between preset rotational speed and actual working rotational speed, and it can control the motor torque via motor controller. |