MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles:Considering Motor Models and Iron Losses

The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.

Effect of Ball Scribing on Iron Loss of CGO and HGO Electrical Steel

The effect of ball scribing on iron loss of conventional grain-oriented ( CGO) and high-permeability grain-oriented ( HGO) electrical steel was investigated. In this paper,ball scribing was achieved by self- designed ball scribing instrument and a computer-controlled system capable of providing high accuracy and automatic measurements was developed for the magnetisation and measurement at high and low flux densities. The results showed that after ball scribing,iron loss of two types of steel ( C711 and H668 ) apparently decreases ( 5. 5% and 8. 2% respectively after 16mm scribing at 1. 2T) ,and at high and low flux densities, CGO and HGO electrical steel performs differently. Through the formation and development of free magnetic poles and secondary magnetic domains due to compressive stress,primary magnetic domain spacing of grain- oriented electrical steel becomes smaller,which reflects as a reduction of iron loss in the macroscopic magnetic properties. Through iron loss formula derivation,the effect of domain refinement on grain-oriented electrical steel was also interpreted.

Research on Iron Loss of Switched Reluctance Starter/Generator for Energy Storage

In order to better realize the energy recovery and storage of hybrid EVs(HEVs),a switched reluctance starter/generator(SRS/G)with both starting and power generation functions is investigated in this paper.First,the iron loss of SRS/G is mainly studied to reduce the motor loss and improve the power generation efficiency.Then,the energy storage of hybrid EVs can be effectively improved.Secondly,a magnetic flux density(MFD)waveforms solution method is proposed to solve the difficulty in calculating the iron loss of the SRS/G.Compared with the commonly used finite element method,the proposed solution method has the advantages of simple,fast and small computational amount.Meanwhile,considering the different operating conditions of SRS/G,the iron loss models for both the time-domain and frequency-domain are established.In addition,the calculation formula of the variable coefficient Bertotti three-term loss separation is improved.As the hysteresis loss coefficient,the Steinmetz coefficient and the stray loss coefficient are respectively fitted by the Fourier fitting method.This method is also applied to solve the iron loss of SRS/G.Finally,through an experimental verification,it is indicated that the development of proposed method has high accuracy.

No-Load Iron Loss Model for a Fractional-Slot Surface-Mounted Permanent Magnet Motor Based on Magnetic Field Analytical Calculation

The common analytical models for the no-load iron loss of permanent magnet(PM)motors usually neglect the iron loss caused by the rotating magnetic field in the tooth tips and the harmonics of the magnetic fields in the teeth and yokes.This paper presents an analytical model for no-load iron loss of a fractional-slot surface-mounted permanent magnet motor.According to the existing analytical model of the magnetic field distribution in the slotted air gap,the magnetic flux densities considering the harmonics of the stator tooth and yoke are both derived based on the continuity of magnetic flux.Due to the complexity of the magnetic field in the tooth tip,the tangential flux density of the tooth tip is approximated by an equivalent sine wave and the radial component is regarded to be the same as that of the corresponding tooth.After obtaining the magnetic fields in stator different regions,the analytical iron loss is calculated by using the Bertotti model and the orthogonal decomposition model.A 20-pole/24-slot PM synchronous motor is taken as an example.The maximum error between the analytical model and finite element model(FEM)is 5.46%,which verifies the validity of the proposed method.

Microstructure of coupled Al/gray cast iron obtained by molding and its effect on mass loss

This study aims to consolidate the surface of gray cast iron with aluminum deposition by developing a method that combines the preparation and surface treatment in a single operation. The effect of the wall thickness of the castings on the microstructure of the formed layers was studied, and two thicknesses, 8 mm and 25 mm, were studied. The formation of a continuous and homogeneous rich aluminum layer on the surface of the cast iron was observed. The formed layer is composed of two successive zones identified as two proeutectoid phases FeAl+FeAl/FeAl2 and single-phase FeAl, which significantly increases the surface hardness. Furthermore, this change in surface composition makes it possible to reduce the mass of the immersed samples in a 1 M hydrochloric acid solution during different exposure times(1 to 4 days). Consequently, a clear improvement in the corrosion resistance of the treated layers is highlighted.

CPS-SPWM级联H桥激励的变压器铁耗快速计算方法

针对载波移相(CPS)正弦脉宽调制(SPWM)级联H桥激励的变压器,提出一种基于经典损耗分离模型的铁耗快速计算方法.首先,结合SPWM电压波形特征定义集总占空比,并推导其关于调制比的解析模型;其次,基于经典损耗分离模型和集总占空比,构建CPS-SPWM级联H桥的铁耗计算模型,该方法可以直接使用调制比、直流母线电压等参数对铁耗进行计算,从而避免传统方法中的谐波分析或者数值积分过程;再次,基于本文铁耗计算模型,提出了一种针对SPWM电压激励的有限元(FEM)仿真等效方法,最后,通过实验验证了本文计算方法的有效性.研究结果表明:等效仿真铁耗误差小于3.6%、仿真用时减少74.5%;最大铁耗计算误差为7.6%.

实际工况下机车牵引变压器铁心损耗模型建立与验证

为实现电力机车牵引变压器的精细化设计,降低产品设计中的冗余量,提高产品的效率减小体积,需要准确预估机车牵引变压器在实际工况下的损耗特性。本文首先模拟牵引变压器实际工作状态,对谐波交变磁化下牵引变压器用电工材料电磁特性的模拟展开研究工作。通过测量牵引变压器实际工作时的电磁特性曲线,分析铁心材料的电磁特性。然后通过对磁化角度和谐波次数的非线性关系研究,建立基于损耗模型系数的磁化角度变系数方程,提出谐波损耗非线性修正系数,进而提高机车牵引变压器损耗模型计算精度。

不同纳米晶铁芯结构下高频变压器空载铁耗特性

为了研究高频变压器采用不同纳米晶铁芯结构时的铁芯损耗分布特性,以工作频率为10kHz,容量为20 kVA的U型、三角型和O型结构纳米晶铁芯为研究对象,对比了3种铁芯空载运行时铁芯不同位置磁密和铁耗分布情况,进一步研究了拐角内径对铁芯局部损耗特性的影响。结果表明:O型铁芯损耗密度分布较均匀,U型和三角型铁芯的损耗密度在磁路直线区域分布均匀;在拐角区域径向方向上,损耗密度减小速度先快后缓,切向方向上损耗密度先增大后减小;U型和三角型铁芯拐角处损耗密度最大值显著大于直线区域,适当增大拐角内径,能够显著降低铁芯的最大损耗密度;实验测得U型、三角型和O型铁芯空载损耗分别为37.3 W、50.5 W和20.5 W,局部热点温度最高分别为46.5℃、55.2℃和35.0℃,明显高于铁芯最高平均温度。

铁尾矿粉对石灰石粉混凝土力学性能和氢氧化钙含量的影响

这是一篇陶瓷及复合材料领域的论文。本文研究了复掺铁尾矿粉和石灰石粉的掺量和比例对混凝土性能的影响。结果表明:随着复掺矿粉比例的不断增大,复掺矿粉混凝土强度均呈现出先增大后减小的变化规律,并在复掺矿粉比例为1∶2时取得较大值。在同一冻融循环次数作用下,混凝土质量损失率随着复掺矿粉比例的增大呈现出先减小后增大的趋势,而混凝土的相对动弹性模量却呈现出先增大后减小的变化趋势。在同一测定位置处,随着复掺矿粉比例的不断增大,复掺矿粉混凝土氯离子含量均呈现出不断减小,且在比例为1∶2时复掺矿粉混凝土氯离子含量的下降变快。综合实验结果得到,石灰石粉掺量为20%时混凝土的强度特性较佳,复掺矿粉比例为1∶2时混凝土的强度和耐久性均达到较佳。

电机损耗研究综述及展望

电机在运行过程中产生大量的热量会导致电机温升过高,从而影响电机正常运行。导致温升的重要原因是来自于电机内部的损耗问题,电机中的损耗主要包括铜损、铁损、机械损耗和杂散损耗四种类型。首先,根据四种损耗类型,从损耗产生原因、损耗计算、损耗影响、降耗方法等方面进行分析,并对四种损耗的计算方法进行研究,其中重点介绍电机铁耗计算分析方法。其次,基于损耗影响因素对电机结构进行优化设计,以通过实例验证降耗方法的可行性。对电机损耗的准确分析,有利于分析电机温升问题,这对设计低损耗、高效率电机有着重要的意义。

不同转速永磁同步电机非晶合金和硅钢选材分析

介绍了非晶材料和硅钢的磁性能,并在高速电机分别采用这两种材料进行仿真,根据仿真结果对比分析了两种材料于电机效率以及不同转速下的铁损差值。并研究了不同转速下电机非晶材料和硅钢铁损的变化规律。结果表明,在高速电机中非晶材料优势明显,为不同转速工况的电机提供选材建议。

PWM激励下电工钢片磁特性测量与结果分析

随着电力电子技术的不断发展,逆变器供电凭借于独特优势已成为电机系统中不可替代的一部分。但是,逆变器供给激励电压中含有大量的高次谐波,由此造成电机的损耗增加明显,对电机的发热、效率、振动噪声都会带来不利影响。所以,为能够最优的设计电机,提高效率,就有必要清楚地掌握电机用电工钢片在实际工作状态下的磁特性和铁芯损耗数据。论文通过使用改进的爱波斯坦方圈,对无取向电工钢片进行了在脉宽调制(Pulse Width Modulation,PWM)激励下磁特性的测量,得到相应铁芯损耗。同时根据测量结果,分析讨论了PWM调制参数和铁芯损耗之间的关系。

激光刻痕降低取向硅钢铁损的研究现状

激光刻痕是降低取向硅钢铁损的有效手段,也是目前唯一在工业生产中得到广泛应用的刻痕技术。本文列举了细化取向硅钢磁畴的各种技术及其优缺点,综述了激光刻痕系统的种类和特点及其研究现状,并对激光刻痕技术的发展进行了展望。

铁尾矿混凝土力学性质及耐久性

这是一篇陶瓷及复合材料领域的论文。为了研究铁尾矿混凝土在受硫酸钠溶液干湿循环作用后的力学特性和耐久性,开展了受硫酸钠溶液侵蚀混凝土的抗压实验、抗氯离子侵蚀实验、抗冻实验和水化特性实验,分析不同铁尾矿掺量、干湿循环次数、溶液浓度对混凝土力学性质和耐久性的影响。结果表明:在铁尾矿掺量为30%、干湿循环次数为60次和硫酸钠浓度为5%时,混凝土的质量损失率较小而抗压强度耐腐蚀系数较大。随着铁尾矿掺量的不断增大,混凝土的抗氯离子侵蚀性能、抗冻性能越好,水化反应放热量不断减小。

巨噬细胞中Piezo1调控铁代谢在年龄相关骨量丢失中的研究

目的对Piezo1蛋白在巨噬细胞参与铁代谢平衡调控中作用作一综述,总结近年来关于年龄相关骨量丢失及巨噬细胞Piezo1的最新研究进展,为治疗年龄相关骨量丢失提供新思路。方法计算机检索CNKI、PubMed等数据库自建库至2023年1月与巨噬细胞Piezo1在年龄相关骨量丢失的相关文献,中文检索关键词为“巨噬细胞、机械敏感性离子通道蛋白、年龄相关骨量丢失、骨质疏松症”,英文检索关键词为“Macrophages、Piezo1、age⁃related bone loss、ARBL、Osteoporosis”,最终将42篇文献纳入。结果与结论巨噬细胞参与铁代谢平衡的调控,骨髓巨噬细胞中Piezo1高表达能导致机体出现铁超载,进而导致ARBL的发生。Piezo1为治疗年龄相关骨量丢失提供了分子层面的新思路和新视角。

基于能量流分析的新能源地下铲运机能耗优化研究

能量流分析是一种分析车辆能量消耗的重要手段,是车辆能耗优化的基础。新能源电池地下铲运机是新型地下矿用设备,对其能量流动与各部件能耗效率研究较少。探究其井下作业的能量损耗是延长其续航时间的研究重点。首次将能量流分析方法应用于新能源铲运机的能耗分析,建立了能量流模型,根据电池温度与铲运机工况设计试验分组并进行工况测试,采集测试数据并基于能量流分析方法对测试结果进行研究。结果表明,新能源铲运机较大的能量损失集中于牵引系统与电池系统。其中驾驶员不适应电驱动操作造成的无效操作与牵引系统控制策略不完善,是导致牵引系统的高能耗的主要因素;电池系统快速充电造成的积温会影响铲运机的能量分配,降低其续航时间。通过对牵引系统与电池系统的优化,实现了新能源铲运机的能耗降低13%。研究结果表明,对新能源铲运机进行能量流分析能够直观了解其能量流动与能耗情况,有助于发现高能耗问题并提出优化方向,从而降低能耗,改善能量利用效率,延长续航时间。

铁死亡在感音神经性耳聋中的研究进展

感音神经性耳聋(sensorineural hearing loss,SNHL)是目前人类最常见的致残性疾病之一,主要表现为耳蜗毛细胞和(或)螺旋神经元损伤所导致的永久性听力损失,而铁死亡是最近才发现的一种调节性细胞死亡形式。迄今为止,铁死亡已被证明参与了许多疾病的病理生理机制,如神经退行性病变、癌症和肾脏疾病等。目前,有相关研究报道铁死亡可能参与了SNHL的发生发展过程。我们就铁死亡机制的研究进展进行综述,阐述其在SNHL中的研究现状及应用前景,为SNHL进一步的研究和治疗提供新思路。

当归补血汤加味联合氨甲环酸序贯抗凝及蔗糖铁治疗全膝关节置换术后隐性失血临床研究

目的:探究当归补血汤加味联合氨甲环酸(TXA)序贯抗凝及蔗糖铁对全膝关节置换术(TKA)后隐性失血的临床疗效。方法:选择TKA治疗的92例患者,依据随机单盲分组法分为对照组和试验组,每组46例。对照组术后接受TXA序贯抗凝及蔗糖铁治疗,试验组在此基础上联合加味当归补血汤进行治疗。比较治疗前后中医症候积分、总体失血量、静脉血栓栓塞症(VTE)发生率、血常规指标[红细胞总数(RBC)、血红蛋白(Hb)、红细胞积压(Hct)]、膝关节功能[美国膝关节协会评分(KSS)]以及疼痛程度[视觉模拟法疼痛评分(VAS)]变化情况。结果:与对照组比较,试验组总失血量、隐性失血量明显较低(P<0.05),显性失血量比较无统计学差异(P>0.05);治疗后,中医证候积分、VAS评分较治疗前显著降低(P<0.05),且试验组中医证候积分、VAS评分显著低于对照组(P<0.05);治疗后,两组RBC、Hb、Hct水平、KSS评分较治疗前显著升高(P<0.05),且试验组RBC、Hb、Hct水平、KSS评分显著高于对照组(P<0.05)。结论:加味当归补血汤联合TXA序贯抗凝及蔗糖铁应用于TKA术后患者,通过降低机体隐性失血量,缓解术后疼痛,从而有效改善术后血虚证相关临床症状,利于术后膝关节功能恢复。

Calculation for Stator Loss of High-Speed Permanent Magnet Synchronous Machine in Torque-speed Envelope and Restraint Approach for Circulating Current in Windings

Iron loss and copper loss are the significant parts of electrical loss of machines,which are the major parts particularly under high frequency condition.High-speed permanent magnet synchronous machines(HS-PMSM)have the benefits of high power density,high efficiency and wide speed range.Which causes the calculation for iron loss and copper loss in whole operating range complex.By analyzing the components and influencing factors of iron loss and copper loss in stator,we have deduced the calculation formula of iron loss and copper loss in whole operating range based on the analytical solution and finite element approach(EFA)solution.According to the calculation solution,taking the influence of operating temperature on the iron loss and copper loss into account,we propose a temperature correction factor and establish the calculation method for the iron loss and copper loss with temperature influences.Finally,by the conductor transposition,we restrain the circulating current under high-frequency operating condition.

硅溶胶粒径对取向硅钢绝缘涂层性能的影响

为了探究不同粒径硅溶胶对取向硅钢绝缘涂层性能的影响,分别对使用至少一种粒径硅溶胶的绝缘涂液及涂层性能进行研究。实验表明:使用小粒径硅溶胶的涂液更稳定,并且能提升涂层与底层的结合程度,具有较大的硬度和较小的铁损;使用大粒径硅溶胶能提升涂液的润湿性能,并能有效提升涂层光泽度,使涂层更容易结晶,按照一定比例混合时还能略微提升涂层的耐腐蚀性能。