基于工作效率最优的功率分流式混合动力系统控制策略研究

Research on Control Strategy of Power Split Hybrid Electric Vehicle Based on Optimal Operation Efficiency

针对一种新型基于双行星排构型的功率分流式混合动力系统,以提高系统工作效率为目标,进行混合动力系统的全局优化控制研究。基于杠杆原理,建立准确反映行星排式混合动力系统转速转矩关系的准静态模型,通过建立各部件效率模型,确定不同工作模式下的系统工作效率,并进行系统工作效率的分析。在此基础上,构建以系统工作效率最优为目标的非线性规划问题,并基于贝尔曼最优原理,采用动态规划算法实现最优控制序列的求解。仿真结果表明:在NEDC测试工况下,相较于基于发动机燃油消耗最优的控制策略,基于工作效率最优的控制策略使车辆等效燃油经济性提高了4. 13%。

Aiming at a novel power split hybrid system with dual planetary gear sets,this paper investigates the global optimal control strategy to improve the system operation efficiency. On the basis of lever analogy,the quasi-static model which reflects the torque and speed relations within the system was established. The system operation efficiency was further decided and analyzed by establishing the efficiency model of each component. Then, the optimal nonlinear programming problem was constructed with the objective to optimize the operation efficiency. On the basis of Bellman optimal principle,the optimal control sequence was obtained by means of dynamic programming. The NEDC( New European Driving Cycle) was used as test cycle. Simulation results indicate that,compared with the strategy which is with the engine fuel consumption as control objective,the vehicle equivalent fuel economy is improved by 4. 13% with the strategy based on the system optimal operation efficiency.