Abstract: To improve the mode transition quality under the mode switching process and the mode operation process without sacrificing the economy performance. A coordinated control strategy based on GA-ECMS torque optimization during driving mode is proposed. Firstly, the real-time optimal operation model and optimized data table of torque under different mode are obtained by the equivalent fuel consumption minimization strategy(ECMS). Secondly, the torque coefficient of the motor is introduced as control variable, the SOC is defined as the state variable and the transition jerk of vehicle is constituted as the objective cost function. Finally, the genetic algorithm(GA) is applied to optimize the torque coefficient of the motor, and coordinated control strategy based on optimization of motor torque coefficient is proposed. A hybrid electric powertrain simulation model is developed on Matlab/Simulink simulation platform, the driving cycle of NEDC and HWFET were used for verification. The results show that under the NEDC cycles, the maximum jerk reduce from 19.45 m s·^-3 to 10.96 m s·^-3, decreased by 43.65%; and under the HWFFET cycles, the maximum jerk reduce from 10.692 m s·^-3 to 5.869 m s·^-3, decreased by 45.11%.The hardware in the loop experiment based on the D2P system used Fuzhou driving cycle is further verified, which shows that the coordinated control strategy based on torque optimization can effectively reduce the transition jerk of vehicle compared to normal strategy, and the fuel economy performance is improved.

Key words: hybrid system, equivalent fuel comsumption minismization stragegy(ECMS), coordinated control strategy, genetic algorithm, drivability