This paper analyses the performance benefit due to electrical overloading of battery pack and electric motors in battery electric vehicles with four wheel-independent drives. The performance enhancement is quantified by relative lap time improvements which are computed using minimum-time optimal control. Additionally, a concurrent optimisation is performed which provides the optimal gear ratios for the front and rear reduction gears as well as the optimal performance distribution between the front and rear motors under the specification of a fixed total motor performance. We characterise the motor performance by the maximum torque, the maximum speed and the overload capability of the electric machines. The essential dynamics are represented using a nonlinear two-track vehicle model and a Thevenin battery model. We propose a simplified modelling approach for electrical overloading using power loss maps and energy reservoirs. This way, we keep the number of additional states low which is advantageous for optimal control problems. Direct optimal control and Hermite-Simpson collocation is used to solve the optimisation problem numerically.

本文分析了四轮独立驱动的电池电动汽车中电池组和电动机的电气过载带来的性能优势。性能增强通过使用最小时间优化控制计算的相对单圈时间改进来量化。此外，在固定总电机性能的规范下，执行并行优化，为前后减速齿轮提供最佳传动比以及前后电机之间的最佳性能分布。我们通过电机的最大扭矩、最大速度和过载能力来表征电机性能。使用非线性双轨车辆模型和戴维宁电池模型表示基本动力学。我们提出了一种使用功率损耗图和能量库的电气过载简化建模方法。这样，我们将附加状态的数量保持在较低水平，这有利于优化控制问题。采用直接最优控制和Hermite-Simpson搭配对优化问题进行数值求解。