scholarly journals Power flow in the air gap of linear electrical machines by utilization of the Poynting vector: Part 1 ‐ Analytical expressions

Author(s):  
Anna E. Frost ◽  
Irina Temiz ◽  
Sandra Eriksson ◽  
Mats Leijon
Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3223
Author(s):  
Gabriel Ekemb ◽  
Fouad Slaoui-Hasnaoui ◽  
Joseph Song-Manguelle ◽  
P. M. Lingom ◽  
Issouf Fofana

This paper proposes time-domain analytical expressions of the instantaneous pulsating torque components in a synchronous machine air gap when supplied by a load-commutated-inverter (LCI) system. The LCI technology is one of the most used variable frequency drives when very high power and low speed are required in applications such as pipeline recompression and decompression, as well as liquefied natural gas compression. In such applications, synchronous motors are used because of their high efficiency resulting from a separated supply of the current to their rotor through the excitation circuit. These applications usually have long and flexible shafts, which are very sensitive to torsional vibration excitation when their natural frequencies interact with any external torque applied to the shaft. A torsional analysis is required by international standards to assess the survivability of the shaft through the overall speed range of the motor. Therefore, the magnitude and frequencies of the motor air-gap torque are needed for such evaluation. The proposed developments are supported by numerical simulations of LCI systems in a large range of operation range. From the simulation results, torque harmonic families are derived and expressed in a parametric form, which confirm the accuracy of the proposed relationships.


Energies ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 165 ◽  
Author(s):  
Yuan Liu ◽  
Aiguo Hu

This paper analyzes the power distribution and flow of an inductive power transfer (IPT) system with two coupled coils by using the Poynting vector. The system is modelled with a current source flowing through the primary coil, and a uniformly loaded secondary first, then the Poynting vector at an arbitrary point is analyzed by calculating the magnetic and electric fields between and around of the two coils. Both analytical analysis and numerical analysis have been undertaken to show the power distribution, and it has found that power distributes as a donut shape in three-dimensional (3D) space and concentrates along the edges in the proposed two-coil setup, instead of locating coaxially along the center path. Furthermore, power flow across the mid-plane between the two coils is analyzed analytically by the surface integral of the Poynting vector, which is compared with the input power from the primary and the output power to the secondary coil via coupled circuit theory. It has shown that for a lossless IPT system, the power transferred across the mid-plane is equal to the input and output power, which validates the Poynting vector approach. The proposed Poynting vector method provides an effective way to analyze the power distribution in the medium between two coupled coils, which cannot be achieved by traditional lumped circuit theories.


1988 ◽  
Vol 71 (1) ◽  
pp. 43-55 ◽  
Author(s):  
K. P. Kovács ◽  
R. Belmans ◽  
W. Geysen ◽  
A. Vandenput

2005 ◽  
Vol 41 (5) ◽  
pp. 2020-2023 ◽  
Author(s):  
G.D. Kalokiris ◽  
T.D. Kefalas ◽  
A.G. Kladas ◽  
J.A. Tegopoulos

2012 ◽  
Vol 721 ◽  
pp. 199-204
Author(s):  
Evangelos M. Tsampouris ◽  
Panagiotis E. Kakosimos ◽  
Charalampos K. Patsios ◽  
Antonios Kladas

Microgrids integrating distributed motor-generator units are commonplace in locomotive and industrial applications. The behavior of these systems is dependent upon various design-operating parameters. However there is a distinct relation between power quality and power flow within these units. This paper presents an analysis of power quality measurements, depicting this interdependence. Respective results can be taken under consideration during power flow programming, enabling enhanced system operation.


1978 ◽  
Vol 15 (1) ◽  
pp. 53-67
Author(s):  
B. L. Jones

Torques in electrical machines are developed largely by iron parts rather than conductors. Simple apparatus has been developed to demonstrate the mechanism of torque production. Analyses in terms of iron surface forces, of changes in coil inductances and of hypothetical air gap conductors are contrasted and compared with measured results.


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