Preface

Currently, electrical machinery is attracting more attention for the development of competitive energy conversion systems with advanced topologies and innovative drives to realize the increasing advantages of current industrial needs. Modern competitive electrical machines must cope with a broad range of applications such as industrial applications, power generation, renewable energy generation, conversion, and domestic home appliance usage, in addition to the new high-performance embedded applications (electric vehicles, aerospace, aircraft machines, robotics, and others). Performance metrics and key differentiators such as small volume, low-high speed operation, high efficiency and torque, good voltage and flux regulations, robustness, flexibility, long lifetime, controllability, good fault-tolerant operating capability are a need for higher competitive electrical machines in the modern renewable energy era. This book is planned to be essentially an introduction to the concepts and developments of emerging electric machines - advances, perspectives, and applications. The book is organized into six chapters as follows:

Chapter 1 presents an introduction to the book.

Chapter 2 analyzes electric machines with axial magnetic flux and the effect of commutation on the electromagnetic moment and electromagnetic power. The chapter considers two types of discrete switching are considered. The analysis is performed for an arbitrary number of phases. The first type of switching involves disabling one phase for the duration of switching. The second type of switching consists of the operation of all phases in the switching interval. Also investigated is the influence of the pole arc and the number of phases on the electromagnetic moment and electromagnetic power. Finally, a conclusion is made about the advantages of the second type of switching.

Chapter 3 examines the detection of faults in stator and rotor asymmetries in wound-rotor induction machines using rotor and stator currents signatures analysis. This method was proposed for experiments in fault diagnosis in engineering courses on electrical machines . The aim is to demonstrate the main steps of developing real-time condition monitoring for wound-rotor induction machines.

Chapter 4 presents the problems of control of asynchronous machines with dual power supply; as a nonlinear structure, the transfer functions depend on the frequency of the stator voltage and the relative slip. This is especially important for wind turbines that need to remain efficient at different speeds. The chapter presents experiments, modeling, and industrial application of control algorithms with positive torque coupling to justify the theoretical findings.

Chapter 5 presents a new, innovative solid bar winding design for electrical machines (either motors or generators) dedicated to electric propulsion. This new winding technique aims to enhance the performance by utilizing the stator slot, increasing the copper fill factor to greater than 75 percent, and reducing the inactive copper at the end-windings. The suggested winding technique hopes to address these challenges.

Chapter 6 presents computationally efficient modeling techniques for a switched reluctance generator to obtain the nonlinear inductance model through the adaptive neuro-fuzzy inference system (ANFIS) and multivariate nonlinear regression technique (MVNLRT). The chapter also gives a comparative analysis of both models along with inferential remarks.

## **Ahmed F. Zobaa**

College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge, United Kingdom

## **Shady H.E. Abdel Aleem**

College of Engineering and Technology, Arab Academy for Science, Technology and Maritime Transport, Giza, Egypt

Assistant to the Editors

## **Ahmed M. Zobaa** Faculty of Engineering, Cairo University, Giza, Egypt

**1**

**Chapter 1**

Introductory Chapter: Emerging

With increasing attention on modern energy conversion (EC) systems, electrical machinery (EM) has been given more and more attention to developing new topologies and innovative drives to realize the increasing advantages of current industrial needs. Direct current (DC) machines, induction machines (IMs), and synchronous machines (SMs) were conventional most commonly used EMs in the industry in the past. Still, IMs, mainly the squirrel-cage IM (SCIM) types, are the most widely used EMs because they provide many advantages like effortless simple control, easy but

EMs' energy consumption in the industry is 40% plus of the total generated energy worldwide [2]; thus, improving the machines' design and efficiency, even the conventional types, can considerably save energy. However, new EMs and their drives are industrialized with many extra features to meet the recent application areas, for example, electric vehicles (EVs), electric ships (ESs), aircraft machines, robotics, wind power generation, automated propulsion systems, and

These machines have to cope with numerous new applications under uncertain operating conditions, e.g. fixed or variable speed, uncertain loads (fixed or variable loads), and alteration of the supply voltage (whether constant or variable

Several factors affect EC systems' efficiency, motor-system efficiency, and the system's performance (from the perspective of power quality (PQ ), energy efficiency, or reliability). For instance, all stakeholders should pay much attention to harmonic distortion problems associated with the variable frequency drives (VFDs), power electronic-based equipment, and nonlinear loads [4], oversizing of equipment distribution losses and power factor of the motors [5], variation of the loading conditions and load management practice (matching between motors and loads at any loading level), maintenance practices (for electrical, electronic and mechanical parts alike, and transmission system issues [6]. Despite the importance of these critical factors, they are often disregarded in practice. Considering these factors can significantly improve efficiency and

enhance the motor systems' power quality and reliability performance.

Electric Machines - Advances,

Perspectives and Applications

*Ahmed F. Zobaa, Shady H.E. Abdel Aleem* 

efficient repair, high efficiency, and low cost and sizes [1].

*and Ahmed M. Zobaa*

**1. Introduction**

others [3].

supply) [1].

**2. Emerging Electric Machines**

## **Chapter 1**
