The characteristic of the hybrid system is that the internal combustion engine system and the motor drive system each have a set of mechanical speed change mechanism. The two mechanisms are combined by gear train or planetary wheel structure, so as to comprehensively adjust the speed relationship between the internal combustion engine and the motor. It has the advantages of series and parallel hybrid system. Compared with the parallel hybrid power system, the hybrid power system can more flexibly adjust the power output of the internal combustion engine and the operation of the motor according to the working conditions. The system is complex and the cost is high.
