Date of Award

12-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Degree Statement

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

Granting Institution

University of Alaska Fairbanks

Committee Chair

Wies, Richard

Committee Chair

Al-Badri, Maher

Committee Member

Huang, Daisy

Table of Contents

Chapter 1: Introduction.

1.1 Problem statement

1.2 Goal statement

1.3 Research objectives

1.4 Research questions

1.5 Research contributions

1.6 Scope and limitations

1.7 Role of electric machines in renewable energy advancement

1.8 Role of finite element methods in electric machine design

1.9 Recent advances in FEA-based electric machine design

1.10 Challenges and future directions in FEA for electric machines

1.11 Thesis organization. Chapter 2: Literature review.

2.1 Principles of electric machines

2.1.1 Synchronous generators

2.1.2 Asynchronous (induction) machines: operation, applications, and advancements

2.2 Evolution of dual stator and rotor design concept

2.3 Previous work on dual-stator electric machines

2.4 Operating principles and topologies of dual-stator machines

2.4.1 Dual stator-single rotor configuration

2.4.2 Dual stator-dual rotor configuration

2.5 Permanent magnetic technology

2.6 Chapter summary.

Chapter 3: Design methodology and specification of dual-stator electric machine.

3.1 Introduction

3.2 Design parameters

3.3 Rotor

3.4 Stator

3.5 Losses in dual-stator synchronous generator

3.6 Harmonic cancellation in electric machines

3.7 Realization of complete dual-stator structure

3.8 Key design considerations

3.9 Summary.

Chapter 4: Results and discussion.

4.1 No-load analysis of proof of concept three-phase dual-stator PMSG

4.1.1 Flux linkage and back-EMF at no-loaf condition

4.1.2 Magnetic flux distribution

4.1.3 Flux leakage and saturation behavior of the coil bridge in dual-stator generator

4.1.4 Magnetic flux distribution in the dual-stator PMSG with rounded coil bridge

4.1.5 Cogging torque of the dual-stator machine

4.1.6 Mesh analysis and boundary conditions

4.2 Load analysis of three-phase dual-stator PMSG

4.2.1 Flux linkage and back EMF at rated load

4.2.2 Electromagnetic torque

4.2.3 Mechanical input and electrical output power of the dual-stator PMSG

4.2.4 Losses and efficiency analysis

4.3 Performance of the proposed dual-stator machine under varying load

4.3.1 Converted torque and input power

4.3.2 Output power and efficiency

4.4 Summary.

Chapter 5: Conclusions and future work.

5.1 Conclusion

5.1.1 Dual-stator electric machine topology

5.1.2 Dual-stator design contributions

5.1.3 Practical applications

5.2 Future work

5.3 Final thoughts

References.

Abstract

Renewable energy has become a persuasive solution for reducing the negative impacts of conventional energy sources and providing sustainable options to rural communities without access to the power grid. As the development of renewable energy advances, electric machines are crucial for efficiently converting and integrating these energy resources into the electrical grid. However, conventional single-stator alternating current electric machines face several challenges that hinder efficient energy conversion, such as harmonic distortion, high core and copper losses due to multi­ple winding groups, and structural complexity. These issues limit their performance, particularly in renewable energy applications such as wind and hydrokinetic power, where efficiency, reliability, and compactness are crucial.

This thesis presents the development of a new, patented dual-accumulator (dual-stator) permanent magnet synchronous generator designed to overcome the limitations of conventional single-stator machines. The patented dual-stator alternating current generator has been simulated using a three­ dimensional finite element analysis software. The design features iron poles in two stators, which are offset by 180', with a coil bridge connecting both stators to promote balanced flux linkage in the two stators. It also uses only three stator coil windings wound on the coil bridge to produce three-phase voltage, simplifying the winding layout and reducing related losses. The performance of this innovative design was examined under no-load and load operating conditions while assess­ing key performance metrics such as harmonic distortion, efficiency, induced voltage, and output power. The results verified the effectiveness of the new design, supporting its application in renew­able energy conversion. The insights provided from this simulation are valuable guidance for the physical development of a prototype.

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