Electrical machines and drives, and their associated power electronics, are a key part of an industrialized society. Reliability is a major challenge in systems design, operation, and maintenance of these technologies. Unreliable systems drive up costs, so diagnostics and fault tolerance become important to help maintain the system and estimate its operational lifetime. Diagnosis and Fault Tolerance of Electrical Machines, Power Electronics and Drives describes techniques for fault analysis, diagnostics, condition monitoring methods, reconfiguration, remedial operating strategies and fault tolerance in electrical machines, power electronics and variable speed drives. It is a must-read for researchers in academia and industry, as well as for manufacturers and advanced students involved with electrical machines.
Inspec keywords: DC-DC power convertors; power capacitors; fault tolerance; invertors; fault diagnosis; power electronics; voltage-source convertors; synchronous machines; electric drives
Other keywords: voltage-source inverter-fed drives; fault diagnosis; DC-DC converters; capacitors; electrical machines; power electronics; fault tolerance; high-power synchronous machine drives; switched reluctance machine drives
Subjects: Synchronous machines; Drives; Power convertors and power supplies to apparatus; General electrical engineering topics; Power electronics, supply and supervisory circuits
Electrical machines, drives, and their associated power electronics, namely, converters and capacitors, play a key role in an ever increasingly technological society. Transportation electrification, renewable energies, and more efficient buildings are just some of the areas where the intensive application of these systems has been most noticed. This book addresses voltage source inverter (VSI)fed drives, switched reluctance machine (SRM) drives, high-power synchronous machine drives, capacitors, and DC-DC converters. The scope of the book encompasses the issues related to fault analysis, fault detection and isolation, diagnostics, prognostics, condition monitoring, post-fault reconfiguration, remedial operation, robust control, and fault tolerance of electromechatronic systems.
The authors discuss condition monitoring, fault diagnosis and prognosis of electrical machines, eccentricity faults, stator inter-turn faults, broken rotor bars or end-rings, demagnetisation of permanent magnets, bearing faults, torque monitoring, magnetic flux monitoring, single-phase rotation test, thermal stress, electrical stress, mechanical stress, fault diagnostic techniques, current-based approaches, voltage-based approaches, fault-tolerant techniques, phase connection and neutral connection to capacitors midpoint, phase connection and neutral connection to an extra invertor leg, series VSI topologies.
Switched reluctance machine drives present a unique ability for fault-tolerant applications due to a high level of electric and magnetic independence between motor phases. This feature allows the machine to keep running with a high degree of safety and low-performance degradation, when a fault occurs in one or more phases. A fault in one of the system phases, either a motor winding fault or a power converter switch fault, can be detected and isolated without causing harmful effects in the other phases. Performance degradation is, of course, proportional to the number of faulty phases. Therefore, fault diagnosis is essential to isolate the fault and promote control and/or hardware reconfigurations to achieve a better performance. In this chapter, the following issues will be addressed: Overall characteristics of switched reluctance motor (SRM) drives; Comprehensive SRM drives fault analysis; Description of suitable diagnostic techniques oriented to machine faults and/or power converter faults; Analysis of diagnostic techniques for open- and/or short-circuit fault detection in power switches that provide faulty element identification;Post-fault reconfiguration strategies based on control reconfiguration and/or hardware reconfiguration.
In this chapter, high power synchronous motor drives will be addressed. First of all, an overview will be provided of the main technologies and design features which characterize large synchronous machines and the relevant supplying converters, also taking into due account their field of application. Subsequently, the attention will be placed on the major strategies intended to improve high-power synchronous machine drives fault tolerance, acting on the system-level drive architecture as well as on the design and operation of the individual components (electric motor, converter, control system). Finally, the main diagnostics and condition monitoring techniques for high-power synchronous motor drives will be covered, describing the main methods to detect possible malfunctioning, anomalies and faults in drive operation before they result in serious damages or hazards.
The book chapter presents the main capacitor technologies, giving a particular emphasis on capacitors commonly used in power converters. The main capacitor diagnostic techniques developed to date are then reviewed in the following sections. Finally, a summary, challenges and future research directions is presented.
This chapter outlined some of the most recent and important advances achieved in the development of fault diagnostic tools and fault-tolerant strategies aimed at DC- DC converters. It is a research topic that has attracted much attention in the last few years, and will certainly continue to attract attentions, due to the compelling need for highly reliable and efficient power conversion solutions for the emerging topic of DC grids. The algorithms available in the literature provide effective fault diagnostic and fault-tolerant solutions for the wide range of DC-DC converter topologies and their typical end-users, allowing to establish a solid framework for the development of reliable DC grids. Still, further developments are required to obtain cheaper and highly reliable DC-DC power conversion solutions.