基于混合储能系统的电动汽车电驱动暂态多域耦合机理与控制研究

The hybrid energy storage system (HESS) may compensate shortages of the battery in electric vehicles due to low specific power. However, nonlinear and large-disturbance high-frequency oscillating and surge currents appear over the battery, since the transient load of the traction motor is highly nonlinear in real operation, the inverter owns the property of high-frequency on/off commutation, and ultracapacitor output could not be self-adaptivly adjusted in all-transient domain. Thus the electrodes may be sufferred from structure collapse and battery lifetime is affected. With an eye on this problem, this study establishes a unified and general transient model of electric drive bridging multiple domains including mechanics, electromagnetics and electrochemistry, and mathematical description for transient multi-domain coupling relation with time- and frequency-domain combination, from standpoint of the entire electric drive system. With respect to it, the impact principles of multiple factors on nonlinear and large-disturbance battery currents could be uncovered. Developing the active power filtering (APF) thoughts to be applied in DC systems, this study creatively integrates motor control and DC-DC converter control and proposes a real-time ripple current compensation and control strategy, which may bring guidance meaning to elimination of nonlinear and large-disturbance battery currents. As a result, this study blends multiple cross-subjects including electric energy storage, electromechanicas and power electronics, and gives theoretical reference to efficiency improvement-based optimal selection of electric drive multi-class parameters.In the meantime, the battery lifetime may be extended thanks to contributions of this study. Consequently the large-scale marketization process could be significantly boosted, bringing in satisfactory economic and social benefits.

蓄电池和超级电容组成的混合储能系统可很好地弥补电动汽车电池储能比功率较低的缺陷。然而由于牵引电机的高度非线性暂态负载特性、逆变器的高频通断换流属性以及超级电容输出无法自适应全暂态调节等，蓄电池端产生非线性大扰动的高频振荡电流和浪涌电流，造成电极材料组织结构塌陷式伤害，从而影响使用寿命。针对这一问题，本项目着眼于电驱动系统整体，创建连接动力、电磁、电化学多域的电驱动统一暂态模型和时域、频域结合的暂态多域耦合关系数学描述，并由此探索多因素对蓄电池非线性大扰动电流发生的影响规律；将有源滤波思想向直流系统发展，创造性地将电机与DC-DC变换器控制有机结合，提出对于蓄电池非线性大扰动电流消除具有指导意义的实时纹波电流补偿控制策略。本研究融合电能存储、电机、电力电子等交叉学科，可为基于效率提高的电驱动多级参数优化提供理论依据；并有望延长蓄电池寿命，促进电动汽车市场化进程，获得良好的经济与社会效益。

在基于混合储能系统的电动汽车电驱动系统中，逆变器的高频通断换流属性、牵引电机高度非线性暂态负载特性以及超级电容输出无法自适应全暂态调节等因素会导致动力电池端产生高频非线性纹波电流，造成电极材料塌陷式伤害，影响电池寿命。针对以上问题，本项目着眼于电动汽车电驱动系统整体，创建了连接动力、电磁、电化学多域的电驱动统一暂态模型和时域、频域结合的暂态多域耦合关系完整数学描述，并由此总结出多因素对蓄电池非线性大扰动电流发生的影响规律；将有源滤波思想向直流系统发展，创造性地将电机与DC-DC 变换器控制有机结合，提出了对于蓄电池非线性大扰动电流消除具有指导意义的直流有源滤波方法。仿真和实验结果表明，电动汽车直流有源滤波方法将动力电池电流的纹波含量降低了70%以上，有效确保了动力电池的平滑性，有利于抑制动力电池老化进程。将混合储能系统中的超级电容置换为电解电容或者膜电容后，可与DC-DC变换器组成独立的电动汽车直流有源滤波模块，随着适配性设计的完成，可以实现在各型电动汽车整车上的广泛应用，提高动力电池的使用寿命，从而整体成本得到较大降低，此外，此直流有源滤波全新技术还有可能进一步由交通领域应用于推广至能源、电力等领域并形成技术核心竞争力。