Advanced Switched Reluctance Machines for Electrified Vehicles

电动汽车正在成为下一代汽车，因为电气化是交通系统提高可持续性、效率、排放、性能和安全性的有效长期解决方案。电动汽车，包括电动汽车(EVS)、混合动力汽车(HEV)和插电式混合动力汽车(PHEV)，在其动力总成中使用一个或多个电动机械。*电动汽车的牵引电机应具有较宽的恒功率范围和较小的过载能力，以适应行驶条件。它们还需要满足关键的行业要求，如可靠性、低成本和低重量、低维护和安静运行。牵引电机应在启动和爬山条件下在低速时提供高扭矩，并应提供高功率以实现高巡航速度。市场上目前可用的大多数混合动力和电动汽车都采用了内部永磁(IPM)同步电机。由于使用了高能、高矫直力的稀土磁体，永磁电机可以提供高转矩密度和平稳运行。然而，永磁体对温度很敏感。这对机器在恶劣环境中的运行造成了很大的限制。此外，稀土磁体在牵引电机的总成本中占据了相当大的比例。与传统汽车相比，电动汽车牵引电机的高成本目前对其大规模生产和市场渗透率的提高构成了挑战。*开关磁阻电机(SRM)在转子上不使用任何永久磁铁或导体。因此，它们可以在恶劣的环境条件下、高速和高温下运行。开关磁阻电机的结构实现了很宽的恒功率转速范围，这与牵引要求非常匹配。由于结构简单，开关磁阻电机的制造成本明显低于永磁电机。开关磁阻电机面临的最大挑战是高扭矩脉动和高水平的噪声和振动。此外，由于定子和转子铁心的不同部分饱和，电机表现出高度的非线性行为。这就在扭矩控制和状态估计方面产生了挑战。此外，高度饱和的运行条件会影响电机的效率。*这项拟议的研究计划专注于一种新型的开关磁阻电机家族，该系列电机具有更高的功率密度、效率和电动汽车的性能。建议的开关磁阻电机系列包括具有各种定子和转子极组合的新型电机配置和先进的控制技术，以提高电机的扭矩和功率密度以及降低扭矩脉动、噪声和振动的性能。**

Electrified vehicles are emerging as the next generation of vehicles because electrification is an effective long-term solution for the transportation system to improve sustainability, efficiency, emissions, performance, and safety. Electrified vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), utilize one or more electric machines in their powertrains. ***Electrified vehicles' traction motors are expected to have a wide constant-power speed range and short overloading capability in order to match with the driving conditions. They also need to meet critical industry requirements such as reliability, low cost and weight, low maintenance, and quiet operation. Traction motors should deliver high torque at low speed for starting and hill-climbing conditions and high power to achieve high cruising speeds. Interior permanent magnet (IPM) synchronous machines are employed in most of the currently available hybrid and electric vehicles on the market. With the use of high-energy and high-coercivity rare-earth magnets, permanent magnet machines can provide high torque density and smooth operation. However, permanent magnets are sensitive to temperature. This causes a significant limitation on the operation of the machine in harsh environments. In addition, rare-earth magnets take up a significant portion of the total cost of the traction motor. When compared with the conventional vehicles, the high cost of the traction motors for electrified vehicles currently presents a challenge for their mass-production and increased market penetration. ***Switched reluctance machines (SRMs) do not employ any permanent magnets or conductors on the rotor. Therefore, they can operate in harsh environmental conditions and at high-speeds and high temperatures. The structure of SRMs enables a wide constant-power speed range, which matches very well with the traction requirements. Due to its simple construction, manufacturing cost of SRMs is significantly lower than the permanent magnet machines. Most significant challenges in SRMs are high torque ripple and high levels of acoustic noise and vibration. In addition, the machine demonstrates a highly nonlinear behavior due to saturation in various parts of the stator and rotor cores. This creates a challenge in terms of torque control and state estimation. Furthermore, highly saturated operating conditions can affect the efficiency of the motor. ***This proposed research program is focused on a novel family of SRMs with improved power density, efficiency, and performance for electrified vehicles. The proposed family of SRMs involves novel motor configurations with various stator and rotor pole combinations and advanced control techniques to improve the torque- and power-density and performance of the motor with reduced torque ripples, acoustic noise, and vibration. **