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改善可持续性、效率、排放、性能和安全性的有效长期解决方案。电气化车辆，包括电动车辆（EV）、混合动力电动车辆（HEV）和插电式混合动力电动车辆（PHEV），在它们的动力系中利用一个或多个电机。 电气化车辆的牵引电机要求具有较宽的恒功率调速范围和较短的过载能力，以适应车辆的行驶条件。它们还需要满足关键的行业要求，如可靠性、低成本和重量、低维护和安静运行。牵引电机应在低速时提供高扭矩，用于起动和爬坡条件，并提供高功率以实现高巡航速度。内置式永磁体（IPM）同步电机被用于市场上大多数当前可用的混合动力和电动车辆。由于使用高能量和高矫顽力的稀土磁体，永磁电机可以提供高转矩密度和平稳运行。然而，永磁体对温度敏感。这对机器在恶劣环境中的操作造成了很大的限制。此外，稀土磁体占据了牵引电机总成本的很大一部分。与传统车辆相比，电动车辆牵引电机的高成本目前对其大规模生产和提高市场渗透率提出了挑战。 开关磁阻电机（SRM）在转子上不使用任何永磁体或导体。因此，它们可以在恶劣的环境条件下以及在高速和高温下运行。SRM的结构使其具有较宽的恒功率转速范围，与牵引要求非常匹配。由于结构简单，SRM的制造成本明显低于永磁电机。SRM中最重要的挑战是高转矩涟漪和高水平的噪声和振动。此外，由于定子和转子铁芯的各个部分的饱和，该机器表现出高度非线性的行为。这在转矩控制和状态估计方面产生了挑战。此外，高度饱和的操作条件会影响电动机的效率。 这项研究计划的重点是一个新的SRMs系列，具有更高的功率密度，效率和性能，适用于电动汽车。所提出的SRM系列涉及具有各种定子和转子极组合的新型电机配置以及先进的控制技术，以提高电机的转矩和功率密度以及性能，同时降低转矩脉动、噪声和振动。

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.