Design and Optimise Synchronous Reluctance Machines in Sensorless Control

This thesis researches the design and fabrication of axially laminated, anisotropic synchronous reluctance rotors with a high saliency ratio and low torque ripple for both three- and five-phase machines. One clear novelty of the research is the first method reported that allows skew to be incorporated in the axially laminated anisotropic (ALA) rotor. The designed rotor is then built with the help of the 3D printing technique which significantly reduces the complexity of the prototyping and fabrication process. The thesis then considers the control necessary including sensorless control schemes for the three- and five-phase synchronous reluctance motors with varying levels of skew. The performance and the effectiveness of the sensorless controllers are verified by experiments for all designed rotors under the three- and five-phase excitation. The three- and five-phase system of the synchronous reluctance motor is first discussed with the stator voltage equations and equivalent circuits. The d-and q-axis inductances are evaluated using finite element analysis. Finite element analysis (FEA) is a common used method in simulating and solving the electrical engineering problems. The FEA shows that for both three- and five-phase motors, the saliency ratio can reach around 10. Further detailed optimization is performed based on the rotor barrier dimensions such as shape, arc length, rib and bridge length, width, and the number of barriers. The final designed rotor in this research is an ALA rotor with 4 poles and 9 layers of magnetic segments. The barrier used is the round-type. The experimental inductances are shown to match the FEA predictions. The method of fabricating an ALA-type rotor with skew is a significant advance in this research. The FEA analysis for both three- and five-phase motor shows that torque ripple can be significantly reduced with the skew process: for instance, the 5.5° skewed rotor and the 9.5° skewed rotor are predicted to offer the best choice for the three- and five-phase stator designs from a parametric study of skew angles. Three skewed rotors are fabricated (5.5 o, 6 o and 9.5o). The experimental results of the torque ripple are compared. For the three-phase case, the rotors with skew shows a good reduction in torque ripple, the 6° skewed rotor performs better than the 5.5° skewed rotor. For the five-phase case, the 9.5° skewed rotor provides the best torque ripple reduction experimentally. The sensorless control is achieved for both three- and five-phase systems. According to the speed demand, the high-frequency injection sensorless control is used when the speed is below 500rpm. To further reduce the transient error, two different sliding mode observer methods are used for three and five-phase systems when the speed demand is above 500rpm. For both three- and five-phase synchronous reluctance motors with non-skewed and skewed rotors, the sensorless control can be successfully implemented. The transient and steady-state errors are all controlled in an acceptable range. By suddenly adding full load at rated and zero speed, the effectiveness of the sensorless control is also verified

Advances in Rotating Electric Machines

It is difficult to imagine a modern society without rotating electric machines. Their use has been increasing not only in the traditional fields of application but also in more contemporary fields, including renewable energy conversion systems, electric aircraft, aerospace, electric vehicles, unmanned propulsion systems, robotics, etc. This has contributed to advances in the materials, design methodologies, modeling tools, and manufacturing processes of current electric machines, which are characterized by high compactness, low weight, high power density, high torque density, and high reliability. On the other hand, the growing use of electric machines and drives in more critical applications has pushed forward the research in the area of condition monitoring and fault tolerance, leading to the development of more reliable diagnostic techniques and more fault-tolerant machines. This book presents and disseminates the most recent advances related to the theory, design, modeling, application, control, and condition monitoring of all types of rotating electric machines

A comprehensive review on brushless doubly-fed reluctance machine

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

A comprehensive review on brushless doubly-fed reluctance machine

The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

Advances in the Field of Electrical Machines and Drives

Electrical machines and drives dominate our everyday lives. This is due to their numerous applications in industry, power production, home appliances, and transportation systems such as electric and hybrid electric vehicles, ships, and aircrafts. Their development follows rapid advances in science, engineering, and technology. Researchers around the world are extensively investigating electrical machines and drives because of their reliability, efficiency, performance, and fault-tolerant structure. In particular, there is a focus on the importance of utilizing these new trends in technology for energy saving and reducing greenhouse gas emissions. This Special Issue will provide the platform for researchers to present their recent work on advances in the field of electrical machines and drives, including special machines and their applications; new materials, including the insulation of electrical machines; new trends in diagnostics and condition monitoring; power electronics, control schemes, and algorithms for electrical drives; new topologies; and innovative applications

The Flux-MMF diagram technique and its applications in analysis and comparative evaluation of electrical machines

The thesis describes a new technique, called the flux-MMF diagram technique, for analysis and comparative evaluation of electrical machines. The technique has evolved from the principle of virtual work, and the -i diagram, used commonly in designing switched reluctance machines and relays. Several applications of this technique are demonstrated in the thesis, supported by experimental validation. These are, the prediction of electromagnetic and cogging torque ripple, modelling of the effect of skew on torque and torque ripple, modelling of the variation of torque constant due to saturation, and comparative evaluation of different types of electrical machines. The thesis shows that the technique can be applied successfully in analysis of a wide variety of electrical machines. These include conventional machines such as the DC commutator, PM brushless AC, Interior PM, and the synchronous reluctance machine; as well as non-conventional machines such as the switched reluctance, PM brushless DC, and the doubly-salient PM machine. The technique has been implemented in a finite-element software, with the help of a link program which links the FE software with the dimensioning or sizing software, such as PC-BDC, produced by the SPEED Laboratory. The link program serves as a vital means of shortening the time it takes to analyse a new design in an FE software, by several orders of magnitude. The thesis also describes a new brushless doubly-salient permanent-magnet machine, called the flux-reversal machine. The design and fabrication process, and the experimental results are presented for a prototype single-phase, high-speed flux-reversal generator. The performance analysis of the prototype based on the flux-MMF diagram technique is included, and this validates its capability in analysing new and non-conventional machines, which cannot be analysed using the classical means

Applications of Power Electronics

Power electronics technology is still an emerging technology, and it has found its way into many applications, from renewable energy generation (i.e., wind power and solar power) to electrical vehicles (EVs), biomedical devices, and small appliances, such as laptop chargers. In the near future, electrical energy will be provided and handled by power electronics and consumed through power electronics; this not only will intensify the role of power electronics technology in power conversion processes, but also implies that power systems are undergoing a paradigm shift, from centralized distribution to distributed generation. Today, more than 1000 GW of renewable energy generation sources (photovoltaic (PV) and wind) have been installed, all of which are handled by power electronics technology. The main aim of this book is to highlight and address recent breakthroughs in the range of emerging applications in power electronics and in harmonic and electromagnetic interference (EMI) issues at device and system levels as discussed in ?robust and reliable power electronics technologies, including fault prognosis and diagnosis technique stability of grid-connected converters and ?smart control of power electronics in devices, microgrids, and at system levels

Advanced propulsion system for hybrid vehicles

A number of hybrid propulsion systems were evaluated for application in several different vehicle sizes. A conceptual design was prepared for the most promising configuration. Various system configurations were parametrically evaluated and compared, design tradeoffs performed, and a conceptual design produced. Fifteen vehicle/propulsion systems concepts were parametrically evaluated to select two systems and one vehicle for detailed design tradeoff studies. A single hybrid propulsion system concept and vehicle (five passenger family sedan)were selected for optimization based on the results of the tradeoff studies. The final propulsion system consists of a 65 kW spark-ignition heat engine, a mechanical continuously variable traction transmission, a 20 kW permanent magnet axial-gap traction motor, a variable frequency inverter, a 386 kg lead-acid improved state-of-the-art battery, and a transaxle. The system was configured with a parallel power path between the heat engine and battery. It has two automatic operational modes: electric mode and heat engine mode. Power is always shared between the heat engine and battery during acceleration periods. In both modes, regenerative braking energy is absorbed by the battery