增程式电动汽车辅助动力单元动态效率特征及其鲁棒控制研究

Auxiliary power unit(APU) works efficiently on the basis of its dynamic efficiency characteristics and in order to work at the determinded efficient point it should work robustly aginst parameters changes, load changes and external disturbance under controlled speed and torque. The traditional steady state efficiency characteristics can't reflect the accurate efficiency characteristics of dynamic process. Firstly, Fractonal order slid mode controllers(FOSMCs) are designed and applied to robus control for speed and torque of APU and make the transient process quick and controllable. The optimal flux linkages of intgrated starter and generator(ISG) under diffrent loads are get through power search method and fuzzy logic. The fractional order inertial component is used to fit the transient optimal flux linkage. The fractional order inertial componets are used to fit the dynamic transmition efficiency between variable speed and torque under controlled transition velocity.This method extends the dimentions of efficiency characterization. Based on the dynamic efficiency characterization and robus quick control, load follow efficiency, quickness and robustness are compared betweent constant speed - variable torque mode and variable speed - variable torque mode, which are tested and verified in the APU - in -loop experiment. Through this study, accurate characterization of APU dynamic efficiency is get and APU can follow load along the transition curve under controlled transition velocity quickly, efficiently and robustly. which improves the APU conversion efficiency and extends the driving range of extended - range electric vehicle(EREV).

辅助动力单元(APU)的动态效率特征是确定其高效工作点的基础，提高APU转速—转矩对参数、负载变化和外界干扰的鲁棒性才能确保APU工作在确定的高效工作点上，传统的发动机和电机的稳态效率不能准确反映其动态工作过程的效率特征。首先采用分数阶滑模变结构控制器实现APU转速、转矩的鲁棒控制及其动态过程的快速可控，采用功率搜索和模糊逻辑寻求ISG电机在各负载功率下的最优磁链，由分数阶惯性环节拟合其动态过渡中的最优磁链；采用分数阶惯性环节拟合发动机、ISG电机以可控的速率在转速、转矩间过渡时的动态效率，扩展效率表征的维度；基于动态效率表征及其鲁棒快速控制，对APU恒转速—变转矩、变转速—变转矩负载跟随中的效率、快速性、鲁棒性进行比较，并在APU在环实验中验证。通过研究，实现APU动态效率精确表征和APU快速、高效、以可控的速率沿着过渡曲线鲁棒地跟随负载，提高APU转换效率，延长增程式电动汽车续驶里程。

增程式电动汽车（Extended Range Electric Vehicle，EREV）是一种纯电驱动的插电式混合动力汽车（Plug-in Hybrid Electric Vehicle，PHEV ），具有动力电池和辅助动力单元（Auxiliary Power Unit，APU）2个能量源，可以实现向纯电动汽车的平稳过渡，是电动汽车产业化发展的重要方向。APU通常由小排量的发动机和启动/发电一体机（Integrated Starter and Generator，ISG）构成，提高APU的工作效率，抑制外界干扰，可以提高APU的控制品质。本研究以APU的电能存储单元—锂离子电池为对象，采用分数阶微积分方法建立了锂离子电池等效电路模型，估算了其荷电状态，较好地描述了电池动态渐变特性；采用基于永磁同步电机损耗模型，以磁链为优化变量，采用搜索法得到PMSM电机稳态下使电机输入功率最小的最优磁链，并采用分数阶惯性环节拟合电机的动态过渡中的最优磁链，采用粒子群算法辨识了分数阶惯性环节参数；分别设计了分数阶滑模变结构转速控制器和滑模变结构直接转矩控制器，实现APU转速、转矩的鲁棒控制；对APU恒转速—变转矩、变转速—变转矩负载不同跟随模式下的效率特征和控制品质进行了研究；采用凸优化和动态规划方法，对比分析和研究了电动汽车能量管理策略，为确定APU工作点奠定基础；研究和构建了昆明市典型公交工况和乘用车工况，并针对昆明典型公交工况对增程式电动客车燃油消耗进行了实际道路试验。通过研究，为增程式电动汽车辅助动力单元高效鲁棒控制提供了较好的解决方案。