基于单电机的多模式混合动力耦合传动动力学机理与控制研究

A hybrid power source coupler using a single electric machine relies on one less electric machine and one less unit of power electronics compared with the popular couplers with two electric machines. Therefore, the single electric machine coupler is significantly helpful for cost reduction and reliability improvement of the hybrid electric vehicles. In order to satisfy the driving demanding, the single electric machine coupler works in multi modes. So mode transition is necessary, and is implemented in a short time through cooperation among the electric machine, engine and clutch. However, intensive jerk and vibration tend to occur during mode transitions when the working point of electric machine transits to a desired distant point defined by both torque and speed. The substantial reason lies in the complicated coupling mechanism between the electromagnetics and mechanical load. During mode transition, the driveline dynamics is affected simultaneously by electromagnetic nonlinearity from the electric machine, friction nonlinearity from the clutch and other from the engine. Resultantly, the relationship between the stator current and the generated electromagnetic torque is extremely nonlinear, and is hard to predict. Hence, the torque and speed control losses accuracy. Addressing this problem, this project proposes a new modeling methodology, which builds a uniform dynamic model for mode transitions by introducing electromagnetics model into the conventional mechanical dynamics model only with friction consideration. By using this model, the dynamic phenomenon affected by flux harmonic, inductance harmonic together with the non-smooth friction nonlinearity can be observed. Moreover, the influencing mechanism of the nonlinear factors on the torque and speed control performance (delay, overshoot and oscillation) of the electric machine can be thoroughly investigated. Further, based on model reference adaptive control theory, a robust control algorithm for mode transitions is studied to achieve acceptable running performance even when the electric machine transits in a big step. The study is significant not only for the application of the hybrid power source coupler using one single electric machine, but for multi-discipline fundamental issues of electromagnetics, nonlinear dynamics and control theory.

单电机多模式混合动力耦合器比较主流双电机耦合器减少一个电机及其控制装置，可有效缓解混合动力汽车成本增加却可靠性降低的矛盾。然而，因单个电机覆盖所有工作模式，在与离合器、发动机协调进行模式切换时，电机工作点需短时间内完成转矩-转速平面二维大跨度迁移，易发生大冲击和抖振，恶化整车行驶平顺性。其根本原因是，电机电磁场与机械负载高度耦合，传动系统受电磁非线性与离合器摩擦非线性等因素综合影响，动力学行为非常复杂，强化定子电流与电磁转矩之间的非线性，严重降低大跨度目标跟踪精度。针对这个问题，本项目提出将电磁学与传统机械动力学、摩擦学相结合，建立模式切换的统一动力学模型，揭示永磁体磁链谐波、电感谐波与非光滑摩擦非线性耦合作用下传动系统动力学行为演化机理，揭示电机转矩、转速控制的延迟、超调量与振荡的变化规律；发展模型参考自适应控制方法，设计对电机转矩和转速跨度具有鲁棒性的模式切换控制策略，抑制冲击与抖振。

单电机多模式混合动力耦合器比较主流双电机耦合器减少一个电机及其控制装置，可有效缓解混合动力汽车成本增加却可靠性降低的矛盾。然而，因单个电机覆盖所有工作模式，在与离合器、发动机协调进行模式切换时，易发生大冲击和抖振，恶化整车行驶平顺性。其根本原因是，电机电磁场与机械负载高度耦合，传动系统受电磁非线性与离合器摩擦非线性等因素综合影响，动力学行为非常复杂。.针对这个问题，本项目开展研究：（1）混合动力系统动力学建模、性能分析与验证，（2）关键因素对混合动力系统动态响应的影响行为，（3）混合动力模式切换的控制策略。.研究发现，（1）混合动力传动系统的实际任务调度周期超过临界值、力控制的速度反馈增益、膜片弹簧负刚度特性、时滞量等可引起传动系统动力学失稳，（2）模型参考控制可实现确定工况下混合动力模式的无缝切换，显著降低冲击度，使之不超过10m/s3，并且减小滑磨功；（3）参考模型参数可调的模型参考自适应控制可适应驾驶意图、行驶环境和不同的动力传动系统参数的变化；（4）两自由度内模控制计算量小，抗干扰能力强，可为模式切换提供新思路。.本项目研究的科学意义在于：（1）在动力传动系统的非线性动力学机理方面的研究丰富了摩擦导入非线性动力学理论，（2）在参考模型参数可调的模型参考自适应控制方面，突破了经典模型参考自适应控制中参考模型参数固定的限制，因而丰富了模型参考自适应控制理论。