Abstract Integrating a multispeed transmission into the electric drive system provides the potential of ulteriorly improving the overall efficiency of battery electric vehicles (BEVs). In this paper, we propose a novel two-speed planetary automated manual transmission (PAMT) which features a more compact mechanical structure than clutchless automated manual transmission (CLAMT) and easier gear shifting control than power-on transmissions. To present the transient behaviours during the gear shifting, a detailed and original dynamical model of the electrified powertrain is developed, including an electric machine (EM), a two-speed PAMT, synchronizer mechanisms, driveline and vehicle, etc. Afterwards, the gear shifting control system is devised, and the gearshift process is orderly divided into five stages based on the proposed control strategy. Next, three alternative planning torque trajectories, i.e., the third-degree polynomial (TDP), the fifth-degree polynomial (FDP) and the seventh-degree polynomial (SDP), are proposed to control the EM torque at the first and the fifth stages of the gear shifting respectively. Subsequently, a series of simulations are performed to validate which candidate torque trajectory is capable of achieving the optimal gear shifting quality in term of reducing the longitudinal vehicle jerk and shift durations. This study provides a beneficial reference for the development of BEVs’ transmission system.

中文翻译：

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一种新型纯电动汽车两档变速器的模型及换挡控制

摘要 将多速变速器集成到电力驱动系统中，可以极大地提高纯电动汽车 (BEV) 的整体效率。在本文中，我们提出了一种新型两速行星式自动手动变速器（PAMT），其机械结构比无离合器自动手动变速器（CLAMT）更紧凑，换档控制比带电变速器更容易。为了呈现换档过程中的瞬态行为，开发了电动动力总成的详细且原始的动力学模型，包括电机 (EM)、两速 PAMT、同步器机构、传动系统和车辆等。然后，齿轮设计了换挡控制系统，并根据所提出的控制策略将换挡过程有序地分为五个阶段。下一个，提出了三个替代的规划扭矩轨迹，即三次多项式（TDP）、五次多项式（FDP）和七次多项式（SDP），用于控制第一和第五阶段的 EM 扭矩。分别换档。随后，执行一系列模拟以验证哪个候选扭矩轨迹能够在减少纵向车辆抖动和换档持续时间方面实现最佳换档质量。该研究为纯电动汽车传动系统的发展提供了有益的参考。建议分别在换档的第一和第五阶段控制 EM 扭矩。随后，执行一系列模拟以验证哪个候选扭矩轨迹能够在减少纵向车辆抖动和换档持续时间方面实现最佳换档质量。该研究为纯电动汽车传动系统的发展提供了有益的参考。建议分别在换档的第一和第五阶段控制 EM 扭矩。随后，执行一系列模拟以验证哪个候选扭矩轨迹能够在减少纵向车辆抖动和换档持续时间方面实现最佳换档质量。该研究为纯电动汽车传动系统的发展提供了有益的参考。