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  • Journal article
    Ng BF, Palacios R, Kerrigan EC, Graham JMR, Hesse Het al., 2015,

    Aerodynamic load control in horizontal axis wind turbines with combined aeroelastic tailoring and trailing-edge flaps

    , Wind Energy, Vol: 19, Pages: 243-263, ISSN: 1095-4244

    This paper presents an aeroservoelastic modeling approach to investigate dynamic load alleviation in large wind turbines with composite blades and trailing-edge aerodynamic surfaces. The tower and rotating blades are modeled using geometrically non-linear composite beams and linearized about reference rotating conditions with potentially arbitrarily large structural displacements. The aerodynamics of the rotor are represented using a linearized unsteady vortex lattice method, and the resulting aeroelastic system is written in a state-space description that is both convenient for model reductions and control design. A linear model of a single blade is then used to design an inline image regulator, capable of providing load reductions of up to 13% in closed loop on the full wind turbine non-linear aeroelastic model. When combined with passive load alleviation through aeroelastic tailoring, dynamic loads can be further reduced to 35%. While the separate use of active flap controls and passive mechanisms for load alleviation has been well-studied, an integrated approach involving the two mechanisms has yet to be fully explored and is the focus of this paper. Finally, the possibility of exploiting torsional stiffness for active load alleviation on turbine blades is also considered.
  • Conference paper
    Puthenpurayil Kunjumuhammed L, Pal BC, 2015,

    Selection of feedback signals for controlling dynamics in future power transmission networks

    , IEEE Power & Energy Society General Meeting, 2015

    This paper deals with the selection of feedback signal(s) that retain the modal behavior of power system electromechanical dynamics under varying operating circumstances. The approach seeks signals that have relatively large magnitude of residue, less variation of the magnitude and phase angle, sufficient gap between the critical pole-zeros, and least sensitive to other modes. The methodology is tested in a 16-machine interconnected power system model with multiple wind farms.
  • Journal article
    Keliris C, Polycarpou MM, Parisini T, 2015,

    Distributed fault diagnosis for process and sensor faults in a class of interconnected input-output nonlinear discrete-time systems

    , International Journal of Control, Vol: 88, Pages: 1472-1489, ISSN: 1366-5820

    This paper presents a distributed fault diagnosis scheme able to deal with process and sensor faults in an integrated way for aclass of interconnected input–output nonlinear uncertain discrete-time systems. A robust distributed fault detection schemeis designed, where each interconnected subsystem is monitored by its respective fault detection agent, and according to thedecisions of these agents, further information regarding the type of the fault can be deduced. As it is shown, a process faultoccurring in one subsystem can only be detected by its corresponding detection agent whereas a sensor fault in a subsystemcan be detected by either its corresponding detection agent or the detection agent of another subsystem that is affected by thesubsystem where the sensor fault occurred. This discriminating factor is exploited for the derivation of a high-level isolationscheme. Moreover, process and sensor fault detectability conditions characterising quantitatively the class of detectable faultsare derived. Finally, a simulation example is used to illustrate the effectiveness of the proposed distributed fault detectionscheme.
  • Journal article
    Chen HT, Choy WCH, Hui SY, 2015,

    Characterization, Modeling, and Analysis of Organic Light-Emitting Diodes With Different Structures

    , IEEE Transactions on Power Electronics, Vol: 31, Pages: 581-592, ISSN: 1941-0107

    This paper demonstrates that organic light-emitting diodes (OLEDs) of different structures can be characterized and modeled using a combination of the photo-electro-thermal (PET) theory and spectral power distribution modeling. The photometric, electrical, thermal, and chromatic properties of OLED devices are incorporated into a model framework so that the performance of the OLED of different structures can be compared. A concept of luminance uniformity over the OLED surfaces is also introduced for comparing OLED with large surface areas. Experimental results are included to verify the OLED models and compare the characteristics of two different OLED samples. Based on the same PET framework, some differences of OLEDs and inorganic LEDs are addressed and discussed.
  • Conference paper
    Jiang J, Astolfi A, 2015,

    Shared-control for the kinematic model of a mobile robot

    , IEEE 53rd Annual Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 62-67

    This paper presents a shared-control algorithm for the kinematic model of a mobile robot. The set of feasible position of the robot is defined by a group of linear inequalities. The shared-control strategy is based on a hysteresis switch and its properties are established by a Lyapunov-like analysis. Simulation results illustrate the effectiveness of the algorithm
  • Conference paper
    Moreno FJ, Merlin MMC, Trainer DR, Green TC, Dyke KJet al., 2015,

    Zero phase sequence voltage injection for the alternate arm converter

    , 11th IET International Conference on AC and DC Power Transmission, Publisher: IET

    The Alternate Arm Converter (AAC) is a voltage source converter being developed as an alternative to the Modular Multilevel Converter (MMC) for HVDC power transmission and reactive power compensation. Each Arm of the converter contains high voltage series IGBT Director Switches and full-bridge cells, which enables the VSC to ride through AC and DC network faults. This paper describes how the AAC can be optimised by modulating the converter terminal voltages with zerophase sequence triplen harmonic components. The optimisation reduces the ratio of the number of the full-bridge cells compared to the simpler Director Switches which offers a valuable improvement in footprint and efficiency.
  • Conference paper
    Boem F, Riverso S, Ferrari-Trecate G, Parisini Tet al., 2015,

    Stochastic Fault Detection in a plug-and-play scenario

    , Pages: 3137-3142, ISSN: 0743-1546

    This paper proposes a novel stochastic Fault Detection (FD) approach for the monitoring of Large-Scale Systems (LSSs) in a Plug-and-Play (PnP) scenario. The proposed architecture considers stochastic bounds on the measurement noises and modeling uncertainties, providing probabilistic time-varying FD thresholds with guaranteed false alarms probability levels. The monitored LSS consists of several interconnected subsystems and the designed FD architecture is able to manage plugging-in of novel subsystems and un-plugging of existing ones. Moreover, the proposed PnP approach can perform the unplugging of faulty subsystems in order to avoid the propagation of faults in the interconnected LSS. Analogously, once the issue has been solved, the disconnected subsystem can be re-plugged-in. The reconfiguration processes involve only local operations of neighboring subsystems, thus allowing a scalable architecture. A consensus approach is used for the estimation of variables shared among more than one subsystem; a method is proposed to define the time-varying consensus weights in order to allow PnP operations and to minimize at each step the variance of the uncertainty of the FD thresholds. Simulation results on a Power Network application show the effectiveness of the proposed approach.
  • Conference paper
    Lawson J, Mitcheson PD, Yates DC, 2015,

    Efficient artificial magnetic conductor shield for wireless power

    , Wireless Power Transfer Conference (WPTC), 2015 IEEE

    Artificial magnetic conductors (AMC) offer a solu-tion to increasing link efficiency in inductive power transfer (IPT)while reducing magnetic fields outside the air gap. A practicaldesign for an artificial magnetic conductor, suitable for use asa shield for inductive power transfer, is presented. The AMCmakes use of a ferrite substrate and lumped capacitor loading. Amodel of the plane wave behaviour of the structure is comparedto simulation and the performance of the AMC compared toother shielding solutions, in an IPT scenario. The plane wavebehaviour is found not to provide a good prediction of the AMCbehaviour in the IPT scenario. The AMC shield is found to offerthe greatest link efficiency, in the IPT scenario.
  • Journal article
    Zhong WX, Zhang C, Liu X, Hui SYRet al., 2015,

    A methodology for making a three-coil wireless power transfer system more energy efficient than a two-coil counterpart for extended transfer distance

    , IEEE Transactions on Power Electronics, Vol: 30, Pages: 933-942, ISSN: 0885-8993

    A new methodology for ensuring that a three-coil wireless power transfer system is more energy efficient than a two-coil counterpart is presented in this paper. The theoretical proof and the conditions for meeting the objective are derived and practically verified in a practical prototype. The key features of the magnetic design are to: 1) shift the current stress from the primary driving circuit to the relay resonator; and 2) generate a large relay current for maximizing magnetic coupling with the receiver coil for efficient power transfer. Consequently, the current rating and cost of the driving circuit can be reduced and the overall quality factor and system energy efficiency are improved. This approach utilizes the combined advantages of the maximum efficiency principle and the use of relay resonator to overcome the energy efficiency problem for applications with extended energy transfer distances.
  • Journal article
    Jerez JL, Constantinides GA, Kerrigan EC, 2015,

    A low complexity scaling method for the Lanczos Kernel in fixed-point arithmetic

    , IEEE Transactions on Computers, Vol: 64, Pages: 303-315, ISSN: 0018-9340

    We consider the problem of enabling fixed-point implementation of linear algebra kernels on low-cost embedded systems, as well as motivating more efficient computational architectures for scientific applications. Fixed-point arithmetic presents additional design challenges compared to floating-point arithmetic, such as having to bound peak values of variables and control their dynamic ranges. Algorithms for solving linear equations or finding eigenvalues are typically nonlinear and iterative, making solving these design challenges a nontrivial task. For these types of algorithms, the bounding problem cannot be automated by current tools. We focus on the Lanczos iteration, the heart of well-known methods such as conjugate gradient and minimum residual. We show how one can modify the algorithm with a low-complexity scaling procedure to allow us to apply standard linear algebra to derive tight analytical bounds on all variables of the process, regardless of the properties of the original matrix. It is shown that the numerical behavior of fixed-point implementations of the modified problem can be chosen to be at least as good as a floating-point implementation, if necessary. The approach is evaluated on field-programmable gate array (FPGA) platforms, highlighting orders of magnitude potential performance and efficiency improvements by moving form floating-point to fixed-point computation.
  • Journal article
    Arana C, Evangelou SA, Dini D, 2015,

    Series Active Variable Geometry Suspension for Road Vehicles

    , IEEE-ASME TRANSACTIONS ON MECHATRONICS, Vol: 20, Pages: 361-372, ISSN: 1083-4435
  • Journal article
    Abraham E, Kerrigan EC, 2015,

    Lower-Order H∞ Filter Design for Bilinear Systems With Bounded Inputs

    , Signal Processing, IEEE Transactions on, Vol: 63, Pages: 895-906, ISSN: 1053-587X
  • Conference paper
    Zhao Z, Yang P, Green TC, Ma Y, Xu Z, Lei J, Guo X, Li Pet al., 2015,

    Steady-State Voltage Stability Analysis and Improvement Strategies of Microgrid With Double Fed Induction Wind Generator

    , 18th International Conference on Electrical Machines and Systems (ICEMS), Publisher: IEEE, Pages: 1063-1068
  • Conference paper
    Zhao Z, Yang P, Xu Z, Green TC, Bottrell Net al., 2015,

    Control Strategy of Energy Storage System for Frequency Support of Autonomous Microgrid

    , 18th International Conference on Electrical Machines and Systems (ICEMS), Publisher: IEEE, Pages: 422-426
  • Journal article
    Luo X, Akhtar Z, Lee CK, Chaudhuri B, Tan S-C, Hui SYRet al., 2015,

    Distributed voltage control with electric springs: comparison with STATCOM

    , IEEE Transactions on Smart Grid, Vol: 6, Pages: 209-219, ISSN: 1949-3053

    The concept of electric spring (ES) has been proposed recently as an effective means of distributed voltage control. The idea is to regulate the voltage across the critical (C) loads while allowing the noncritical (NC) impedance-type loads (e.g., water heaters) to vary their power consumption and thus contribute to demand-side response. In this paper, a comparison is made between distributed voltage control using ES against the traditional single point control with STATic COMpensator (STATCOM). For a given range of supply voltage variation, the total reactive capacity required for each option to produce the desired voltage regulation at the point of connection is compared. A simple case study with a single ES and STATCOM is presented first to show that the ES and STATCOM require comparable reactive power to achieve similar voltage regulation. Comparison between a STATCOM and ES is further substantiated through similar case studies on the IEEE 13-bus test feeder system and also on a part of the distribution network in Sha Lo Wan Bay, Hong Kong. In both cases, it turns out that a group of ESs achieves better total voltage regulation than STATCOM with less overall reactive power capacity. Dependence of the ES capability on proportion of critical and NC load is also shown.
  • Journal article
    Moreno R, Moreira R, Strbac G, 2015,

    A MILP model for optimising multi-service portfolios of distributed energy storage

    , Applied Energy, Vol: 137, Pages: 554-566, ISSN: 0306-2619

    Energy storage has the potential to provide multiple services to several sectors in electricity industry and thus support activities related to generation, network and system operation. Hence aggregating the value delivered by storage to these sectors is paramount for promoting its efficient deployment in the near future, which will provide the level of flexibility needed to deal with the envisaged high renewables share and the increase in peak demand driven by transport and heating electrification. In this context, we develop a Mixed Integer Linear Programming (MILP) model to schedule operation of distributed storage by coordinating provision of a range of system services which are rewarded at different market prices. The model maximises distributed storage’s net profit while providing distribution network congestion management, energy price arbitrage and various reserve and frequency regulation services through both active and reactive power control. We demonstrate benefits associated with the coordination of these services and its impacts on commercial strategies to determine optimal multi-service portfolios in the long term. We also demonstrate the value of reactive power control to support not only distribution network congestion management, but also efficient trading of energy and balancing services which are usually treated through active power-only control. In addition, we use the model to price the service of distribution network congestion management and propose an efficient investment policy to upgrade distribution network capacity in the presence of distributed storage. Finally, several case studies under current market conditions in Great Britain (GB) demonstrate that distributed storage revenues associated with frequency control services are significantly more profitable.
  • Journal article
    Zhang X, Green TC, Junyent-Ferre A, 2015,

    A New Resonant Modular Multilevel Step-Down DC-DC Converter with Inherent-Balancing

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 30, Pages: 78-88, ISSN: 0885-8993
  • Journal article
    Lin D, Chua L, Hui S-Y, 2015,

    THE FIRST MAN-MADE MEMRISTOR: CIRCA 1801

    , PROCEEDINGS OF THE IEEE, Vol: 103, Pages: 131-136, ISSN: 0018-9219
  • Conference paper
    Manfredi S, Angeli D, 2015,

    Consensus of time-varying nonlinear non-autonomous networks with application to field sampling by mobile robots

    , 54th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 4848-4853, ISSN: 0743-1546
  • Conference paper
    Kiziroglou ME, Elefsiniotis A, Kokorakis N, Wright SW, Toh TT, Mitcheson PD, Schmid U, Becker T, Yeatman EMet al., 2015,

    Scaling of dynamic thermoelectric harvesting devices in the 1-100 cm<SUP>3</SUP> range

    , Conference on Smart Sensors, Actuators, and MEMS VII 1st SPIE Conference on Cyber-Physical Systems, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
  • Conference paper
    Forni P, Angeli D, 2015,

    Input-to-State Stability for cascade systems with decomposable invariant sets

    , 54th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 3742-3747, ISSN: 0743-1546
  • Conference paper
    Angeli D, Casavola A, Tedesco F, 2015,

    Economic Model Predictive Control with Parameter-Varying Cost and Guaranteed Average Performance

    , 54th IEEE Conference on Decision and Control (CDC), Publisher: IEEE, Pages: 4314-4319, ISSN: 0743-1546
  • Conference paper
    Angeli D, Casavola A, Tedesco F, 2015,

    Theoretical advances on Economic Model Predictive Control with time-varying costs

    , 5th IFAC Conference on Nonlinear-Model-Predictive-Control (NMPC), Publisher: ELSEVIER, Pages: 272-277, ISSN: 2405-8963
  • Conference paper
    Clerckx B, Bayguzina E, Yates DC, Mitcheson PDet al., 2015,

    Waveform optimization for Wireless Power Transfer with nonlinear energy harvester modeling.

    , Publisher: IEEE, Pages: 276-280
  • Conference paper
    Zhao Z, Yang P, Guerrero JM, Xu Z, Green TC, Lei J, Guo X, Li Pet al., 2015,

    Dynamic Stability Analysis of Autonomous Medium-Voltage Mixed-Source Microgrid

    , 41st Annual Conference of the IEEE-Industrial-Electronics-Society (IECON), Publisher: IEEE, Pages: 1801-1806, ISSN: 1553-572X
  • Conference paper
    Jiang H, Kiziroglou ME, Yates DC, Yeatman EMet al., 2015,

    A NON-HARMONIC MOTION-POWERED PIEZOELECTRIC FM WIRELESS SENSING SYSTEM

    , 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), Publisher: IEEE, Pages: 710-713
  • Conference paper
    Kkelis G, Yates DC, Mitcheson PD, 2015,

    Comparison of Current Driven Class-D and Class-E Half-Wave Rectifiers for 6.78 MHz High Power IPT Applications

    , 3rd IEEE Wireless Power Transfer Conference (WPTC), Publisher: IEEE
  • Conference paper
    Papadaskalopoulos D, Fatouros P, Strbac G, 2015,

    Addressing Demand Response Concentration under Dynamic Pricing

    , PowerTech, 2015 IEEE Eindhoven, Publisher: IEEE
  • Conference paper
    Zhao Z, Yang P, Xu Z, Green TC, Bottrell Net al., 2015,

    Control Strategy of Energy Storage System for Frequency Support of Autonomous Microgrid

    , 18th International Conference on Electrical Machines and Systems (ICEMS), Publisher: IEEE, Pages: 422-426
  • Conference paper
    Zhao Z, Yang P, Green TC, Ma Y, Xu Z, Lei J, Guo X, Li Pet al., 2015,

    Steady-State Voltage Stability Analysis and Improvement Strategies of Microgrid With Double Fed Induction Wind Generator

    , 18th International Conference on Electrical Machines and Systems (ICEMS), Publisher: IEEE, Pages: 1063-1068

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