أحمد عايض علي آل مريع
مجال التميز 
تميز دراسي و بحثي 


البحوث المنشورة 

البحث (1): 

عنوان البحث: 
Design And Analysis Of A Flux Concentrated Linear Vernier Hybrid Machine With Consequent Poles 
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تاريخ النشر: 
22/05/2019 
موجز عن البحث: 
In low speed applications, variable reluctance permanent magnet machines are often proposed due to their efficient use of magnet material and high torque density. This becomes even more important in large linear applications, where the translator is longer than the stator. Often, however, very low power factors are experienced by this class of machine. This paper proposes a Vshape flux concentrated version of a consequent pole linear Vernier hybrid permanent magnet machine and compares it to a surface mounted magnet variant. Using finite element analysis validated by two laboratory prototypes, it is shown that the flux concentrated version increases the airgap flux density, which potentially leads to an improvement in the force density and efficiency, or can be used to increase the operating power factor. 


البحث ( 2): 

عنوان البحث: 
A Cylindrical Linear Permanent Magnet Vernier Hybrid Machine For Wave Energy 
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تاريخ النشر: 
02/11/2018 
موجز عن البحث: 
In some wave energy converters, there is a need for linear electrical machines where all the active parts are mounted on the stator. For this reason the linear Vernier hybrid machine has been investigated. In other research, it is analyzed in 2D and assumed to have a flat crosssection. In this paper a cylindrical version of the Vernier hybrid machine is presented and analyzed. A geometrical model is used to investigate potential mass savings of the cylindrical version, and a finite element analysis design study is used to demonstrate a potential improvement in performance. A proof of concept laboratory scale model has been built and tested to validate the predictions. 
البحث (3): 

عنوان البحث: 
Evaluating Alternative Linear Vernier Hybrid Machine Topologies For Integration Into Wave Energy Converters 
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تاريخ النشر: 
04/10/2018 
موجز عن البحث: 
This paper discusses the development of linear Vernier Hybrid Machines for use in wave energy converters. A number of topology options are explored to reduce magnet usage and improve performance for use as a linear generator. Consequent pole, Vshape and Halbach arrays are designed for a target 25kW specification. A discussion of overall cost of energy produced is used to justify using efficiency and power factor to asses fixed magnet mass topology variants. A power factor improvement from 0.38 to 0.72 is presented. Physical integration of the electrical machine into wave energy converters is considered including flooded experimental results of thermal behavior and polymer bearing wear. 


المؤتمرات العلمية: 



المؤتمر (1): 

عنوان المؤتمر: 
2017 IEEE International Electric Machines And Drives Conference (IEMDC) 
تاريخ الإنعقاد: 
2124 May 2017 
مكان الإنعقاد: 
Miami, FL, USA 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Development Of A DoubleSided Consequent Pole Linear Vernier Hybrid PermanentMagnet Machine For Wave Energy Converters 
ملخص المشاركة: 
Wave energy conversion can be simplified by using direct drive linear generators which may improve reliability. Numerous topologies of direct drive linear generators have been proposed in the last few decades such as the linear vernier hybrid permanent magnet (LVHPM) machine. However, the cost of this kind of machine is driven by the quantity of permanent magnet (PM) material. This paper proposes a linear vernier hybrid permanent magnet machine with consequent pole and concentrated windings for wave energy converters, which requires less magnet material for comparable performance. The key of the proposed design is the modular stator where the unbalanced magnetic circuit caused by consequent pole can be eliminated. Based on finite element analyses (FEA) the present machine is capable of higher thrust force, higher back EMF and lower cogging force as well as force ripple compared to that of a baseline LVHPM machine. 
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المؤتمر (2): 

عنوان المؤتمر: 
2017 IEEE International Electric Machines And Drives Conference (IEMDC) 
تاريخ الإنعقاد: 
2124/05/2017 
مكان الإنعقاد: 
Miami, FL, USA 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
An ECore Linear Veriner Hybrid Permanent Magnet Machine With Segmented Translator For Direct Drive Wave Energy Converter 
ملخص المشاركة: 
This paper proposes a new topology of a Linear Veriner Hybrid Permanent Magnet (LVHPM) machine with Ecore stators and a segmented chamfered translator, which is shown to give mass reduction and better magnetic flux path compared to existing designs. Linear Permanent Magnet (PM) generators have the capability to reduce the number of moving parts, providing a simpler mechanical drive train when used as an allelectric direct drive power takeoff for wave energy converters. The translator can be directly connected to a heaving buoy, or similar, to translate linear motion from the ocean waves into electricity. In this paper, the electromagnetic performance including magnetic flux, back EMF, cogging, thrust force, thrust ripple as well as force density of the new segmented chamfered translator design is analyzed in Finite Element Analysis (FEA). The proposed design is compared with two different models and shown to produce the best performance among those models. 
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المؤتمر (3): 

عنوان المؤتمر: 
2018 XIII International Conference On Electrical Machines (ICEM) 
تاريخ الإنعقاد: 
36/09/2018 
مكان الإنعقاد: 
Alexandropoulos, Greece 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
A New Configuration Of A Consequent Pole Linear Vernier Hybrid Machine With VShape Magnets 
ملخص المشاركة: 
This paper proposes a new flux concentrated version of a consequent pole linear Vernier hybrid permanent magnet machine. The Vernier hybrid machine stator has alternatively magnetised adjacent magnets directly in contact with each other. A salient rotor then switches the direction of flux past the stator coils. Alternate magnets can be removed to make the consequent pole version, where inset rectangular magnets are magnetized in a common direction and separated by soft magnetic poles. In a flux concentrated consequent pole configuration, each magnet pole comprises of two magnets forming a V shape. This topology hence possesses a combination of consequent poles, flux concentration and flux switching machine topologies. Magnetic flux concentration increases the airgap flux density, which potentially leads to an improvement of the force density and operating power factor. This paper compares the inset and V shape consequent pole topologies using finite element analysis simulations. Both machines have the same dimensions, magnet volume, rated speed and current density. The simulation results imply that the Vshape machine offers higher electromagnetic performance. To confirm this, two linear prototypes are currently under construction, where the key parts that already produced are presented in this paper. 
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المؤتمر (4): 

عنوان المؤتمر: 
2018 XIII International Conference On Electrical Machines (ICEM) 
تاريخ الإنعقاد: 
36/09/2018 
مكان الإنعقاد: 
Alexandropoulos, Greece 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Development And Testing Of A Novel Cylindrical Permanent Magnet Linear Generator 
ملخص المشاركة: 
Vernier hybrid machines are known for their simple salient translator structure and inherent magnetic gearing, making them a strong candidate for low speed, high force applications. As the armature coil and the magnets are both mounted on the stator, linear versions of this machine are attractive for high amplitude systems. In most configurations, single sided or double sided flat cross sections are considered, giving a two dimensional flux path. In this paper, a cylindrical variant of the double sided configuration is presented, where the flux path is now three dimensional. Guiding operating equations are given as well as the three dimensional finite element analysis (FEA) used to design a prototype. Details and test results of a soft magnetic composite (SMC) based laboratory prototype for a cylindrical Vernier hybrid machine are given which demonstrate the concept and validate the simulation results. 
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المؤتمر (5): 

عنوان المؤتمر: 
20th International Conference On Electrical Machines And Systems (ICEMS) 
تاريخ الإنعقاد: 
1114/08/2017 
مكان الإنعقاد: 
Sydney, NSW, Australia 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
An Investigation Of A Linear Flux Switching Machine With Tapered Ferromagnetic Poles 
ملخص المشاركة: 
This paper investigates methods of magnet mass reduction in linear flux switching permanent magnet (LFSPM) machines by introducing tapered consequent poles. Based on the finite element analysis (FEA) three different models are designed, investigated and compared. The obtained results indicate that by adopting the proposed tapered ferromagnetic poles a considerable saving of material cost and weight is obtained without sacrificing the machine performance. 
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المؤتمر (6): 

عنوان المؤتمر: 
20th International Conference On Electrical Machines And Systems (ICEMS) 
تاريخ الإنعقاد: 
1114/08/2017 
مكان الإنعقاد: 
Sydney, NSW, Australia 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Investigation Of A Doubly Salient Halbach Array Linear Permanent Magnet Machine For Wave Energy Converters 
ملخص المشاركة: 
In this paper a novel Ecore Linear Variable Reluctance Vernier Hybrid Permanent Magnet (LVRVHPM) machine with inherent magnetic gearing is proposed for use in the long stroke application of a wave energy converter. The proposed topology is a combination of a doubly salient flux reversal machine, a consequent pole machine and a surface mounted Halbach array Permanent Magnet (PM) machine. The stator teeth interact with horizontally and vertically magnetized PM and ferromagnetic poles in such a way as to maximize the flux density in the machine by minimizing flux leakage. The translator is segmented to ensure the most effective use of material for minimum mass. A performance comparison study between the novel LVRVHPM machine, a baseline linear Vernier Hybrid Permanent Magnet (VHPM) machine, a linear Halbach VHPM machine and a linear Consequent pole VHPM machine is used to show that the best result is achieved by the combined topology. All four designs consist of the same double sided Ecore stators, segmented translators and an equal magnet mass. 
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المؤتمر (7): 

عنوان المؤتمر: 
European Wave And Tidal Energy Conference  EWTEC 2017 
تاريخ الإنعقاد: 
27/08/201701/09/2017 
مكان الإنعقاد: 
Cork. Ireland 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Electric Machine Design For Wave Energy Converters 
ملخص المشاركة: 
Direct Drive Wave Energy has a unique set of requirements for an ideal power take off. The slow speed reciprocating nature of many primary movers leads designers to use either intermediate mechanical systems or force dense machine types. There is a play off between electrical machine capital cost, mass, efficiency, force ripple and power factor. This paper presents the development of a case study wave energy device and uses it as the basis to assess a number of machine topologies for use as the direct drive power take off. The aim is that it can be used to aid future electrical machine design studies for other devices. 
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المؤتمر (8): 

عنوان المؤتمر: 
2017 IEEE Region 10 Humanitarian Technology Conference (R10HTC) 
تاريخ الإنعقاد: 
2123/12/2017 
مكان الإنعقاد: 
Dhaka, Bangladesh 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Interior Permanent Magnet Synchronous Machine (IPMSM) Design For Environment Friendly Hybrid Electric Vehicle (HEV) Applications 
ملخص المشاركة: 
The Interior Permanent Magnet Synchronous Machine (IPMSM) is becoming an integral part in Hybrid Electric Vehicle (HEV) applications due to their excellent performance, fast development and environment friendliness. While depending on the rare earth magnet materials and rotor structure for the dynamic characteristics, they are very useful in high speed application especially for variable speed drives. This paper is about designing Interior Permanent Magnet (IPM) motors for hybrid electric car application with fractional slot pole combination in order to achieve maximum efficiency with lowest possible costing. It additionally incorporates imperative assumptions and estimations of machine parameters that can be utilized for genuine machine outline. Two IPM machines have been designed, simulated and analyzed by 2D Finite Element analysis (FEA) for lowest possible torque ripple, iron loss, cogging torque and harmonic distortion. Optimized back EMF, cogging torque, rated torque, machine volume, pricing and other simulation results are compared for both the machine. Finally the study ends up with the selection of the better machine with respect to the efficiency, size, torque ripple and cost effectiveness. 
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المؤتمر (9): 

عنوان المؤتمر: 
7th International Conference On Renewable Power Generation (RPG 2018) 
تاريخ الإنعقاد: 
2627/09/2018 
مكان الإنعقاد: 
Copenhagen, Denmark 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
An Investigation Into Linear Generators With Integrated Magnetic Gear For Wave Energy Power Take Off 
ملخص المشاركة: 
This work presents a new wave energy converter power take off system that combines two recent developments in drive train technology, the consequent pole linear Vernier hybrid permanent magnet machine and the linear magnetic gear. The combined system is fully realised in 3D FEM and compared to a similar direct drive machine. While the resulting system is lighter, reducing the active material mass by 30%, and more efficient, the system requires larger amounts of high cost permenant magnet material and increased power take off complexity. It is summarised that while such a system could be recomended in certain conditions, it is not viable for general application. 
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المؤتمر (10): 

عنوان المؤتمر: 
7^{th} International Conference On Renewable Power Generation (RPG 2018) 
تاريخ الإنعقاد: 
2627/09/2018 
مكان الإنعقاد: 
Copenhagen, Denmark 
طبيعة المشاركة: 
Paper presentation 
عنوان المشاركة: 
Development of a Linear Vernier Machine with Low Translator Mass for Wave Energy Power Takeoff 
ملخص المشاركة: 
This paper presents a Linear Variable Reluctance Permanent Magnet (LVRPM) machine where the armature winding and inset Halbach array Permanent Magnets (PMs) are mounted on Ecore stators. The Halbach array consists of a vertically magnetised PM pole and a salient ferromagnetic iron pole (split teeooth) sandwiched between two horizontal PMs. The segmented translator consists solely of laminations with salient iron poles. As a variable reluctance machine, it exhibits inherent magnetic gearing and a higher force and power density than the conventional synchronous PM machines. Finite Element Analysis (FEA) has been used to investigate the effect of machine parameters. The logical development of the LVRPM from the more conventional Vernier Hybrid machine is presented, including a nearly 50% reduction in magnetic flux leakage and a higher flux per unit magnet mass. 
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