New method for power allocation of multi-power sources considering speed-up transient vibration of planetary power-split HEVs driveline system

Abstract

Abstract One of the major issues for hybrid electric vehicles (HEVs) powertrain is the torsional vibration in the process of speed-up condition, which is unavoidable. The broader goal of this article is to re-examine the classical gear transmission machinery transient vibration problem in the context of a 4 + N degree of freedom nonlinear torsional system that essentially describes a planetary coupling transmission system (PCTS) of HEVs example, and further provide a new method for power allocation of multi-power sources considering speed-up transient vibration of planetary power-split HEVs driveline system. In particular, resonant amplifications during acceleration, as excited by angular displacement-based meshing stiffness of gear teeth, are investigated using a nonlinear torsional model, and the transient vibration predictions are successfully compared with test bench results. Then a quasi-linear model during acceleration process is proposed and numerically solved to obtain the transient vibration acceleration as well as its envelope curve. Dynamic response results of PCTS are also successfully compared and analyzed under different speed-allocation rules. Finally, an improved genetic algorithm method is applied to construct optimal relationship between the motor speeds and vehicle speeds, and the influences of vibration character and energy consumption are successfully considered in multi-optimized function. Experimental results under the speed-up condition show that transient vibration acceleration of the optimized powertrain is decreased within the safe range, thus new power-allocation solutions provide more insight to the enhancement of planetary power-split HEVs quality.