Series-parallel coupling control method and system of hybrid power system

A parallel to series coupling control method of a hybrid power system, the hybrid power system comprises a first power source, a second power source, a power output terminal, and a generator unit, and drives a load through the power output terminal, wherein the generator unit is driven by the second power source to generate an electric power when the second power source is actuated, the parallel to series coupling control method comprises:

• driving the power output terminal with the first power source and the second power source at the same time;
• and
• upon receiving a parallel to series conversion command, performing a parallel to series conversion procedure, which comprises:
• increasing an output torque of the first power source and an input torque of the generator unit at the same time, the rate of increasing the output torque being substantially equal to the rate of increasing the input torque;
• and
• when the output torque of the first power source is substantially equal to the total torque needed by the load, cutting off the driving relationship between the second power source and the power output terminal and driving the power output terminal with the first power source.

A hybrid power system, generating a driving force to drive a load, the hybrid power system comprises:

• a first power generation unit, for generating a first power;
• a second power generation unit, for generating a second power;
• and
• a main controller, for selectively controlling the system to drive the load in a series mode or a parallel mode, wherein in order to control the system to drive the load in the series mode, the main controller controls the first power to drive the load, and in order to control the system to drive the load in the parallel mode, the main controller controls the first power and the second power to drive the load at the same time;
• when the main controller switches the series mode to the parallel mode, the main controller enhances a rotation speed of the second power generation unit, and when the rotation speed of the second power generation unit is substantially equal to a rotation speed of the first power generation unit, the main controller controls the first power generation unit and the second power generation unit to drive the load at the same time.