Abstract: Basing on an analytical of hydraulic drive hybrid power system,a new closed hydraulic drive hybrid power system is proposed.The basic principle of the system and the transfer process of the kinetic energy are introduced,and the mathematical model of the transfer of the kinetic energy during braking is established and the simulation analysis is carried out.The result shows that the braking process is stable,the energy recovery is effective,the design of the system and the calculation of the element parameters are reasonable.The result of the study has reference value to the study of the hybrid technology in the future.

Key words: hydraulic drive hybrid power, planetary gear, pump/motor, closed hydraulic transmission