Abstract: Aiming at the problem of global optimization algorithm, i.e. the huge amount of calculation and the uncertainty of penalty function in optimization objective, a hierarchical optimization framework is proposed, in which the optimization on bottom layer control is realized by using instantaneous optimal control strategy while the optimization on top layer is achieved by global optimization strategy. Meanwhile, the boundary solving method based on constrained termination state is adopted, effectively avoiding enormous debugging work for achieving the electricity balance of battery and raising calculation efficiency. The simulation results show that the optimization algorithm enhances the overall efficiency of system and further reduces the fuel consumption of vehicle

Key words: planetary hybrid powertrain, global optimization, instantaneous optimal control, constrained termination state