Study On Energy Management Strategy For A New Type Of Power-split Transmission

Power-split system, acting as a kind of electrical continuous variable transmission, can achieve high dynamic efficiency, which enables it to become the most promising choice for hybrid electrical vehicles’ powertrain system. Compared with traditional continuous variable transmission, the power-split system dispense with speed change device, which is the main reason for energy dissipation. However, the power-split system possesses various working mode while improving efficiency.Therefore, the core techniques have been carried out a research in this paper, whose goal, through comparing transmission component’s connection schema logically; matching subsystem parameters reasonably; optimizing dynamic resources’ working mode coherently, is to ameliorate energy efficiency of transmission system. In general, included are those followings work:Firstly, a new type of power-split transmission system was proposed, aiming at it can be controlled effortlessly and has a comprehensive working mode; the connection of power-split device has been applied through lever analogy method and power analyzing method, which helps to describe characteristics of power-split system and to analyze dynamic power flowing of power-split device.Secondly, the dynamic and economical parameters of new-type power-split system have been designed based on Chinese criterion which relate to hybrid and electrical vehicles. According to these standard parameters, the characteristic parameter of pivotal components of transmission system have been matched through theoretical formula calculation method and driving cycle analysis method. A simulation model for dynamic transmission system has been constructed in Simulink subsystem of MATLAB software. Specifically, an approach that combined theoretical formula calculation with experimental data has been applied for the construction of dynamic components model; an approach that based on system’s characteristic has been applied to the construction of vehicle control system, and a tool that based on fuzzy system for the construction of simulated driver model.Besides, a rules-based control strategy has been employed, by taking basic principle of establishing transmission system working mode into consideration, to research power-split system’s energy management. Moreover, the vehicle’s driven mode, by considering battery system’s state of charge as reference standard parameter, has been classified into charge-depleting and charge-sustain mode; aiming at the equivalent specific fuel consumption of combined system which consists of engine and motor, optimized is the dynamic resources’ output torque of each working mode which is possessed by proposed power-split system, which is the parameters foundation for energy management strategies.Last but not least, the optimized parameters were conducted into power-split transmission system’ simulated numerical model, aiming at carrying out a simulation calculation in terms of vehicle’s dynamical and economical parameters. In result, dynamic parameters such as maximum climbing capacity, maximum speed, and electric mileage are chose to validate the feasibility of proposed power-split system; economical parameters such as state of charge and contrast cycle vehicle speed are choose to validate the effectiveness and rationality of established energy management strategies.