Study Of Control Method For The Propulsion System Of Hybrid Electric Vehicle Based On Driving Cycle

At present most of the conventional control strategy is to calculate the theoretic target value in order to minimize the fuel consumption and emission. With the constraint condition of driving cycles and the power performance, the optimal working point then is calculated based on the assumption that all the optimal working points are able to be realized well, that makes the control strategy equal to the control method. Although the optimized targets of the conventional control strategy are different, most of them have not take into account the dynamic characteristics of the HEV system. In that case, it is likely to worsen the dynamic characteristics of the HEV, and what is worse, it will prevent the optimization target being actualized.First, the conventional HEV dynamic control methods at home and abroad have been compared to each other. According to the problems of HEV control methods, the necessity of HEV dynamic control method based on driving cycle is bringing forward. Aim at the 1.5L test vehicles of parallel HEV, the HEV whole vehicle model has been established with Simulink at the base of HEV structure and its dynamic principle. And then the verification of power performance and fuel economy for the whole vehicle model is finished with compute simulation.According to the request of the HEV dynamic characteristics in driving cycle, via optimizing the PI control parameters and vehicle speed closed loop control, then the HEV dynamic characteristics have been improved. But there are some problems, when the HEV dynamic characteristics is pursuing lavish, the drive ability and dynamic response of the HEV power system will be insufficient, and then the optimization goal for HEV control strategy will be worse. In order to solve the problems above, the motor torque dynamic modification control method is used for the HEV power dynamic control. Through the use of motor excellent dynamic characteristics, the HEV torque request will be modified dynamically. So the HEV power dynamic and the optimization goal will achive.Finally, separately in step velocity condition, HEV mode switching condition and the cyc1015 conditon, the simulation test and platform test for HEV power control method have been carried out. In the simulation test with Simulink, the control effects of the conventional HEV control method have been compared to the control method mentioned in the paper, such as the HEV dynamic characteristics, vehicle torque request, the motor input torque and the engine input torque, fuel consumption, motor effect and so on. It indicates that the HEV dynamic characteristics have been improved and the HEV power is effective controlled. At last, the platform tests for the motor dynamic control of HEV powertrain have been done.