复合功率分流系统发动机起动模型预测控制

复合功率分流混合动力系统从纯电动模式至电子无级变速(Electronic-continuously variable transmission,E-CVT)混合动力模式的切换过程,伴随发动机的起动。由于发动机在整个起动过程始终与传动系相连,其低速往复脉动阻力矩特性对车辆模式切换过程的驾驶平顺性有直接影响,若控制不当,常引起较大的车辆纵向冲击。针对复合功率分流混合动力系统模式切换过程,基于Matlab/Simulink平台建立传动系动态模型和发动机阻力矩模型;提出一种发动机起动模型预测优化控制策略,在线计算电机转矩拖转发动机跟踪目标最优转速曲线并补偿输出端转矩波动。离线仿真及硬件在环台架试验结果表明,所开发的发动机模型预测转速跟踪控制策略能够快速起动发动机并使车辆平稳切换,将整车纵向冲击度限制在11.0m/s3以内,且对整车参数摄动具有较好的鲁棒抑制效果。

Model Predictive Control of Engine Start-up for Compound Power-split Hybrid Powertrain

When the compound power split hybrid system transitions from pure electric mode to hybrid mode, the engine always starts.However, because the engine is always connected to the driveline during start-up process, its low-speed reciprocating pulsation resistance torque has a direct impact on the driving smoothness of the vehicle. If improperly controlled, it often causes a large longitudinal jerk of the vehicle. For the engine start-up process of the compound power-split hybrid system, the power-split hybrid powertrain model and the engine resistance torque model are established based on the Matlab/Simulink platform. An engine start-up optimization mode predictive control strategy is proposed and the motor torque is calculated online to track the optimal engine speed curve and compensate for output torque fluctuation. The offline simulation and hardware-in-the-loop test results show that the proposed model predictive speed tracking control strategy can not only achieve rapid engine start,but also smoothly complete the mode transition. Besides, it limits the vehicle's longitudinal jerk within 11.0 m/s³ and has a good robust suppression on vehicle parameter perturbation.