Optimization Design of High-speed Interior Permanent Magnet Motor with High Torque Performance Based on Multiple Surrogate Models

In order to obtain better torque performance of high-speed interior permanent magnet motor(HSIPMM) and solve the problem that electromagnetic optimization design is seriously limited by its mechanical strength, a complete optimization design method is proposed in this paper. The object of optimization design is a 15 kW、20000 r/min HSIPMM whose permanent magnets in rotor is segmented. Eight structural dimensions are selected as its optimization variables. After design of experiment(DOE), multiple surrogate models are fitted, a set of surrogate models with minimum error is selected by using error evaluation indexes to optimize, the NSGA-II algorithm is used to get the optimal solution. The optimal solution is verified by load test on a 15 kW, 20000 r/min HSIPMM prototype. This paper can be used as a reference for the optimization design of HSIPMM.

Analysis of Temperature Rise in High-Speed Permanent Magnet Synchronous Traction Motors by Coupling the Equivalent Thermal Circuit Method and Computational Fluid Dynamics

To solve the problem of temperature rise caused by the high power density of high-speed permanent magnet synchronous traction motors,the temperature rise of various components in the motor is analyzed by coupling the equivalent thermal circuit method and computational fluid dynamics.Also,a cooling strategy is proposed to solve the problem of temperature rise,which is expected to prolong the service life of these devices.First,the theoretical bases of the approaches used to study heat transfer and fluid mechanics are discussed,then the fluid flow for the considered motor is analyzed,and the equivalent thermal circuit method is introduced for the calculation of the temperature rise.Finally,the stator,rotor loss,motor temperature rise,and the proposed cooling method are also explored through experiments.According to the results,the stator temperature at 50,000 r/min and 60,000 r/min at no-load operation is 68℃ and 76℃,respectively.By monitoring the temperature of the air outlets inside and outside the motor at different speeds,it is also found that the motor reaches a stable temperature rise after 65 min of operation.Coupling of the thermal circuit method and computational fluid dynamics is a strategy that can provide the average temperature rise of each component and can also comprehensively calculate the temperature of each local point.We conclude that a hybrid cooling strategy based on axial air cooling of the inner air duct of the motor and water cooling of the stator can meet the design requirements for the ventilation and cooling of this type of motors.

The Slot Number and Air-Gap Effect on Performance of the High-Speed Brushless Permanent Magnet Motor

This paper describes the key issues of high-speed brushless permanent magnet motor design, such as rotor design, stator design, and determination of the main dimensions, and the overall design process was given. In this paper, a two-pole three-phase high-speed brushless PM （permanent magnet） motor with ratings air-gap length and stator slot number on the motor performance of 7.5 kW, 30,000 rpm is designed, and the effect of the different was analyzed. The results show that larger number of stator slot decreases the rotor loss and the rotor torque ripple. Larger air-gap length decreases the rotor loss.

A sensorless efficiency test system for a high-speed permanent magnet synchronous motor

We present a sensorless efficiency test system with energy recovery for a high-speed permanent magnet synchronous motor(PMSM). In the system, two identical high-speed PMSMs are used as the motor under test(MUT)and the load machine(LM),respectively.A new sensorless vector control(VC) method based on a hypothetical reference frame is presented to control both the MUT and the LM.Also,a regenerating unit is used to implement energy circulation to save energy.Experiments were carried out on a prototype, with a digital controller based on the TMS320 F28335, to verify the adequacy of the sensorless VC method.As a result,the efficiency test system achieves the load test at the speed of 21000 r/min without any reduction equipment. During the test, the energy regenerated by the LM could be fed back to the MUT by the regenerating unit, and 81.31% electrical power was saved.In addition, with the proposed sensorless VC method,both the MUT and the LM can work at i_d = 0 without a position sensor.

潜液式液化天然气泵用低温永磁同步电机研究现状综述

低温永磁同步电机具有高效率、高功率密度和运行稳定的优点,正在逐步替代低温感应电机,成为液化天然气泵用低温电机未来的发展趋势,但仍有一些关键技术问题有待解决。该文首先详细阐述了低温环境下永磁同步电机关键材料的电磁特性和机械特性的变化规律,明确了不同材料的选取原则。在此基础上,重点总结了低温永磁同步电机的设计方法、拓扑结构、多物理场耦合分析及控制策略等关键技术。然后,介绍了现有低温电机的制造工艺与测试方法,指出当前低温电机测试所面临的挑战和不足。最后,探讨了低温永磁同步电机领域亟待解决的关键技术问题,并对低温永磁同步电机的研究方向和发展趋势进行了展望。

低温高速永磁电机转子屏蔽套的设计及强度分析

针对低温泵用高速永磁电机的屏蔽套厚度和过盈量的确定问题,从电机转子强度的角度分析,提出了以厚度最小化作为设计目标的研究方法。首先确定转子各材料的强度约束准则,建立电机转子的三维有限元强度计算模型,并通过解析法验证,分析了分别采用钛合金和碳纤维作为屏蔽套材料时不同转速和温度下转子应力的变化规律,探究各材料的失效极限;并以此作为约束条件,确定了符合强度要求的屏蔽套厚度及过盈量,最终得到的碳纤维屏蔽套较钛合金的厚度更小,在强度方面更具优势。该屏蔽套的设计方法在满足转子强度的前提下,使得材料尽限利用,对低温泵用电机和高速电机的屏蔽套设计具有参考意义。

LNG泵用低温高速永磁电机三维电磁场与涡流损耗的分析计算

针对液化天然气(liquefied natural gas,LNG)泵用低温高速永磁电机换相频率高、损耗大的问题,研究低温高速永磁电机三维电磁场与涡流损耗的分布特征及变化规律。结合电机材料低温电磁特性,构建电机三维全域瞬态电磁场-路耦合有限元数学模型,揭示低温高速永磁电机端部磁场的衰减规律。分析护套属性对永磁体涡流损耗的影响,探索低温与常温环境下永磁体涡流损耗的差异性,并进一步研究电流换相动态过渡过程永磁体与护套涡流电密的瞬时变化特性,得到转子瞬时涡流损耗的分布曲线,确定电机端部结构件中涡流电密及涡流路径的分布。分别从电磁参数、转子涡流损耗数值以及电磁转矩的角度对模型以及计算结果进行验证。

LNG泵用低温高速永磁电机转子摩擦损耗研究

以一台额定转速为35000 r/min的低温高速永磁电机为例,研究电机转子在液化天然气(LNG)中的摩擦损耗。为得到低温高速永磁电机转子LNG摩擦损耗随电机转速的变化规律,基于流体力学原理,建立三维流体场物理模型,对不同转速下电机转子LNG摩擦损耗进行计算,并分别考虑介质轴向流速、介质温度、转子表面粗糙度等因素对电机转子LNG摩擦损耗的影响,揭示电机转子LNG摩擦损耗与各个影响因素之间的数值关系。同时,利用解析法计算不同转速下电机转子LNG摩擦损耗。将解析计算结果与数值计算结果进行对比,验证数值法的有效性。此外,对比空气对电机转子摩擦损耗的影响,随着电机转速的变化,电机转子LNG摩擦损耗的变化规律与空气摩擦损耗变化规律相似。

LNG泵用低温高速永磁电机偏心故障动态电磁力

针对低温环境下材料性质改变引起的电机电磁力性能变化问题,本文对低温高速永磁电动机在偏心故障前后的电磁力分布和变化进行了分析,提出一种基于麦克斯韦张量法的电磁力计算模型,在此基础上对护套表面位置、定子齿顶、定子齿壁偏心故障前后的电磁力进行计算,并与常温下电磁力进行了比较。定量阐述了偏心故障前后电磁力的演变规律与应力集中位置,从电磁场参数、电磁转矩以及气隙电磁力时空特性三个角度验证了电磁力计算结果的合理性。电磁力的分析方法与结果为同类电机的电磁力计算提供了借鉴,为电机形变分析及结构优化设计奠定了基础。

永磁屏蔽泵在乙烯装置的应用

低温甲烷泵是乙烯生产装置深冷分离技术中的关键设备。原工艺技术专利商针对该泵输送的介质具有介质轻、温度低、易燃易爆等工艺特性,选择了以甲醇为密封介质带压密封罐结构的密封形式。运行以来,该密封频繁失效,造成冷箱甲醇冻堵,乙烯损失严重,多次进行改造和试用,效果不佳。借装置升级改造时机,换型为永磁屏蔽泵,有效地解决低温甲烷泵机封频繁出现泄漏的问题,实现乙烯装置深冷分离区域“乙烯零损失”的降本增效目标。

潜液式低温永磁同步电机的设计与特性研究

潜液式低温永磁同步电机是液化天然气(LNG)泵的关键核心驱动部件,其工作性能至关重要。针对电机在LNG(161℃)低温环境下的运行特点,考虑降低LNG的气化量、提高机械应力等方面性能,提出一种适用于LNG泵用低温永磁同步电机的设计方法、理论分析低温对材料特性及电磁参数的影响,建立“电磁-流体-热-应力”多物理耦合的有限元仿真模型,最后设计一台11kW,6 000r/min的LNG泵用潜液式低温永磁同步电机样机。出于安全考虑,在196℃液氮环境下搭建样机测试台并进行试验研究,验证了理论分析的正确性。

液氮泵用低温永磁同步电机电磁设计

低温环境下电机材料电磁特性变化,导致常规电磁设计方法不适用液氮泵用永磁同步电机。本文提出一种基于类比法的液氮泵用低温永磁同步电机的快速设计方法,探讨了低温永磁电机电磁负荷及电流密度选取、电磁设计理论推导和电磁特性分析,并对电机输出转矩进行优化。结果表明:电机的电流密度选取不宜过小,在8~12 A/mm^(2)较为合适。为达到绕组热平衡,电机线负荷与电流密度的选取大致呈反比的关系。设计的低温永磁电机较常温永磁电机体积缩小约32%,且电磁特性基本保持一致,验证了设计方法的有效性。转矩优化后平均转矩提升了3.8%,转矩脉动降低了0.5%,达到了电机输出转矩要求。