Abstract:The problem of poor fuel economy of traditional high-powered tractors has promoted the development of hybrid tractors, and the problem that the output speed of power take-off (PTO) cannot be decoupled from the running speed of tractors, which made the electronic continuously variable transmission (ECVT) tractors of planetary gear popularized, but the power cycle phenomenon of ECVT of planetary gear reduced the shunting efficiency. Therefore, the power-split principle and power cycle generation mechanism of 2K-H epicyclic gear train were analyzed based on the lever balance method. A lever topology method for ECVT configuration design of high-powered hybrid tractor was proposed to search feasible configurations efficiently. The final scheme of ECVT configuration of high-horsepower hybrid tractor was put forward, and its feasibility was verified. Firstly, the ECVT configuration was topologized by lever topology method and power output-split principle. Then the optimal configuration was optimized by analyzing the transmission characteristics of each topological configuration. By installing clutches and brakes to meet the needs of tractor operation and the feasibility of various mode switching. The rear drive system was matched with high and low gears, main reduction and wheel reduction to form the final configuration scheme. At the same time, the dynamic characteristic equations of the four working modes of this configuration were derived, and the feasibility of decoupling output between PTO speed and tractor speed was clarified. Finally, the simulation analysis of energy-saving control of the whole hybrid tractor based on ECVT energy management strategy based on dynamic programming algorithm was carried out under plowing and rotary tillage conditions respectively. The results showed that compared with the comparison configuration, the proposed ECVT configuration can reduce the equivalent fuel consumption by about 5.17% under ploughing condition and about 5.11% under rotary tillage condition, which can effectively improve the fuel economy of the high-horsepower hybrid tractor. There was no power cycle phenomenon under two working conditions, which ensured the smooth operation and split efficiency of the hybrid power transmission system. The decoupling output of PTO speed and tractor speed was realized, which provided a solution for the independent speed control of PTO shaft independent of tires. The proposed energy management strategy was helpful to the energy-saving control of hybrid power system.