DC-link capacitors are an important part in the majority of power electronic converters which contribute to cost, size and failure rate on a considerable scale. From capacitor users' viewpoint, this paper presents a review on the improvement of reliability of dc link in power electronic converters from two aspects: 1) reliability-oriented dc-link design solutions; 2) conditioning monitoring of dc-link capacitors during operation. Failure mechanisms, failure modes and lifetime models of capacitors suitable for the applications are also discussed as a basis to understand the physics-of-failure. This review serves to provide a clear picture of the state-of-the-art research in this area and to identify the corresponding challenges and future research directions for capacitors and their dc-link applications.

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Reliability of Capacitors for DC-Link Applications in Power Electronic Converters—An Overview

This paper presents an overview of motor drive technologies used for safety-critical aerospace applications, with a particular focus placed on the choice of candidate machines and their drive topologies. Aircraft applications demand high reliability, high availability, and high power density while aiming to reduce weight, complexity, fuel consumption, operational costs, and environmental impact. New electric driven systems can meet these requirements and also provide significant technical and economic improvements over conventional mechanical, hydraulic, or pneumatic systems. Fault-tolerant motor drives can be achieved by partitioning and redundancy through the use of multichannel three-phase systems or multiple single-phase modules. Analytical methods are adopted to compare caged induction, reluctance, and PM motor technologies and their relative merits. The analysis suggests that the dual (or triple) three-phase PMAC motor drive may be a favored choice for general aerospace applications, striking a balance between necessary redundancy and undue complexity, while maintaining a balanced operation following a failure. The modular single-phase approach offers a good compromise between size and complexity but suffers from high total harmonic distortion of the supply and high torque ripple when faulted. For each specific aircraft application, a parametrical optimization of the suitable motor configuration is needed through a coupled electromagnetic and thermal analysis, and should be verified by finite-element analysis.

Overview of Electric Motor Technologies Used for More Electric Aircraft (MEA)

The main objective of this two-part state-of-the-art paper called “Recent Advances in the Design, Modeling, and Control of Multiphase Machines” is to present latest contributions in the multiphase machines' field. The first part of this paper focuses on the recent progress in the design, modeling, and control, whereas the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, particularly in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.

Recent Advances in the Design, Modeling, and Control of Multiphase Machines—Part II

In this paper, two online schemes for an integrated design of fault-tolerant control (FTC) systems with application to Tennessee Eastman (TE) benchmark are proposed. Based on the data-driven design of the proposed fault-tolerant architecture whose core is an observer/residual generator based realization of the Youla parameterization of all stabilization controllers, FTC is achieved by an adaptive residual generator for the online identification of the fault diagnosis relevant vectors, and an iterative optimization method for system performance enhancement. The performance and effectiveness of the proposed schemes are demonstrated through the TE benchmark model.

Real-Time Implementation of Fault-Tolerant Control Systems With Performance Optimization

There are numbers of alternative energy resources being studied for hybrid vehicles as preparation to replace the exhausted supply of petroleum worldwide. The use of fossil fuel in the vehicles is a rising concern due to its harmful environmental effects. Among other sources battery, fuel cell (FC), super capacitors (SC) and photovoltaic cell i.e. solar are studied for vehicle application. Combinations of these sources of renewable energies can be applied for hybrid electric vehicle (HEV) for next generation of transportation. Various aspects and techniques of HEV from energy management system (EMS), power conditioning and propulsion system are explored in this paper. Other related fields of HEV such as DC machine and vehicle system are also included. Various type models and algorithms derived from simulation and experiment are explained in details. The performances of the various combination of HEV system are summarized in the table along with relevant references. This paper provides comprehensive survey of hybrid electric vehicle on their source combination, models, energy management system (EMS) etc. developed by various researchers. From the rigorous review, it is observed that the existing technologies more or less can capable to perform HEV well; however, the reliability and the intelligent systems are still not up to the mark. Accordingly, this review have been lighted many factors, challenges and problems sustainable next generation hybrid vehicle.

Hybrid electric vehicles and their challenges: A review

This paper considers existing more electric technologies in commercial aircraft and observes modern reliability data and redundancy techniques to highlight the reasons restricting the application of new components featuring electric drives and electromechanical actuation. Two techniques for maintaining a constant torque when faulted are applied to two very different fault-tolerant drives. Taking into consideration the test results and reliability data, conclusions are drawn as to the suitability of these and other drive configurations with regard to the stringent aerospace reliability and fault tolerance standards.

Fault-Tolerant Design Considerations and Control Strategies for Aerospace Drives

Research is increasingly focusing on the incorporation of electromechanical actuators into future More Electric Aircraft. For an actuator to be feasible in a commercial aircraft, the most critical design factor is attaining the strict safety requirements. The electrical drives used in More Electric technologies must also be suitable for the conventional power supply and control arrangements of aircraft, otherwise feasibility of a new technology may be reduced. This study discusses the generic design requirements for electromechanical actuators from a safety perspective, including the application of fault-tolerant electric drives. Later, two prototype electromechanical actuators, developed by the authors are discussed, comparing the different topologies.

Safety-critical design of electromechanical actuation systems in commercial aircraft

This paper proposes a novel online condition monitoring system of dc-link metallized polypropylene capacitors in fault-tolerant drives for aerospace applications. The estimation technique makes use of voltage and current sensors which are already in place for protection and control purposes. The novel aspect of the proposed technique relates to monitoring capacitors in real time while the motor is operational. No external interferences, such as injected signals or special operation of the drive, are required. The condition monitoring system is independent of torque and speed and hence independent of a variation in the load. The condition monitoring system is validated using manual calculations, simulation, low-voltage experimentation, and high-voltage implementation on an aerospace drive.

Condition Monitoring of DC-Link Capacitors in Aerospace Drives

This paper considers the electrical actuation of aircraft wing surfaces, with particular emphasis on flap systems. It discusses existing hydraulic and electrohydraulic systems and proposes an electrical alternative, examining the potential system benefits in terms of increased functionality, maintenance, and life-cycle costs. This paper then progresses to describe a full-scale actuation demonstrator of the flap system, including the high-speed electrical drive, step-down gearbox, and flaps. Detailed descriptions of the fault-tolerant motor, power electronics, control architecture, and position sensor systems are given, along with a range of test results, demonstrating the system in operation.

https://eprints.ncl.ac.uk/file_store/production/155219/740AC78D-7D3A-421C-A4C6-443D503F9936.pdf

J. W. Bennett

Papers

Overview of Electric Motor Technologies Used for More Electric Aircraft (MEA)

Fault-Tolerant Design Considerations and Control Strategies for Aerospace Drives

Safety-critical design of electromechanical actuation systems in commercial aircraft

Condition Monitoring of DC-Link Capacitors in Aerospace Drives

A Prototype Electrical Actuator for Aircraft Flaps