scholarly journals Optimized design of a high-power-density PM-assisted synchronous reluctance machine with ferrite magnets for electric vehicles

2017 ◽  
Vol 66 (2) ◽  
pp. 279-293 ◽  
Author(s):  
Xiping Liu ◽  
Ya Li ◽  
Zhangqi Liu ◽  
Tao Ling ◽  
Zhenhua Luo

AbstractThis paper proposes a permanent magnet (PM)-assisted synchronous reluctance machine (PMASynRM) using ferrite magnets with the same power density as rareearth PM synchronous motors employed in Toyota Prius 2010. A suitable rotor structure for high torque density and high power density is discussed with respect to the demagnetization of ferrite magnets, mechanical strength and torque ripple. Some electromagnetic characteristics including torque, output power, loss and efficiency are calculated by 2-D finite element analysis (FEA). The analysis results show that a high power density and high efficiency of PMASynRM are obtained by using ferrite magnets.

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2141 ◽  
Author(s):  
Yuqing Yao ◽  
Chunhua Liu ◽  
Christopher H.T. Lee

Multiphase machines have some distinct merits, including the high power density, high torque density, high efficiency and low torque ripple, etc. which can be beneficial for many industrial applications. This paper presents four different types of six-phase outer-rotor permanent-magnet (PM) brushless machines for electric vehicles (EVs), which include the inserted PM (IPM) type, surface PM (SPM) type, PM flux-switching (PMFS) type, and PM vernier (PMV) type. First, the design criteria and operation principle are compared and discussed. Then, their key characteristics are addressed and analyzed by using the finite element method (FEM). The results show that the PMV type is quite suitable for the direct-drive application for EVs with its high torque density and efficiency. Also, the IPM type is suitable for the indirect-drive application for EVs with its high power density and efficiency.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 113
Author(s):  
Bo Wang ◽  
Gaurang Vakil ◽  
Ye Liu ◽  
Tao Yang ◽  
Zhuoran Zhang ◽  
...  

Permanent magnet synchronous machines provide many dramatic electromagnetic performances such as high efficiency and high power density, which make them more competitive in aircraft electrification, whereas, designing a permanent magnet starter–generator (PMSG), with given consideration to fault tolerance (FT), is a significant challenge and requires great effort. In this paper, a comprehensive FT PMSG design process is proposed which is applied to power systems of turboprops. Firstly, potential slot/pole combinations were selected based on winding factor, harmonic losses and manufacture issues. Then, pursuing high power density, a multiple objective optimization process was carried out to comprehensively rank performances. To meet a fault tolerance target, electrical, magnetic and thermal isolation topologies were investigated and compared, among which 18 slot/12 pole with dual three-phase was selected as the optimal one, with a power density of 7.9 kW/kg. Finally, a finite element analysis verified the performance in normal and post-fault scenarios. The candidate machine has merits concerning high power density and post-fault performance.


Author(s):  
Xiping Liu ◽  
Ya Li ◽  
Zhangqi Liu ◽  
Tao Ling ◽  
Zhenhua Luo

Purpose The purpose of this paper is to propose a permanent magnet-assisted synchronous reluctance machine (PMASynRM) using ferrite magnets with the same power density as rare-earth PM synchronous motors used in Toyota Prius 2010. Design/methodology/approach A novel rotor structure with rectangular PMs is discussed with respect to the demagnetization of ferrite magnets and mechanical strength. Some electromagnetic characteristics including torque, output power, loss and efficiency are calculated by 2D finite element analysis. Findings The results of the analysis show that a high power density and high efficiency for PMASynRM can be achieved using ferrite magnets. Originality/value This paper proposes a novel rotor structure of PMASynRM with low-cost ferrite magnets that achieves high power density as permanent machines with rare-earth PMs.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.


2011 ◽  
Vol 4 (5) ◽  
pp. 052104 ◽  
Author(s):  
Di Liu ◽  
Yongqiang Ning ◽  
Yugang Zeng ◽  
Li Qin ◽  
Yun Liu ◽  
...  

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