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 th...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.展开更多
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 d...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.展开更多
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 ...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.展开更多
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 ...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.展开更多
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Pi...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。展开更多
基金Supported by the Major Science and Technology Project Servo Drive and Motor Test Specification and Standard Research and Test Platform(2012ZX04001051).
文摘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.
基金supported in part by National Natural Science Foundation of China(NSFC)under Project No.51737010.
文摘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.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 51174057 and 51274062)National High Technology Research and Development Program (Grant No. 2012AA03A503)
文摘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.
文摘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.
文摘目的对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。
