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  • Patent
    Rogers DJ, Green TC, 2010,

    Method And Apparatus For Performing On-Load Mechanical Switching Operations

    An electrical device comprising: a first current path having a primary switch therein, and means for coupling to an electrical supply; and a diversionary current path having semiconductor switching means therein, the semiconductor switching means being operable to bypass the primary switch; the device being arranged such that, in use, a first current flowing from the supply along the first current path can be diverted, on the operation of the semiconductor switching means, along the diversionary current path, bypassing the primary switch; wherein the diversionary current path comprises a controllable electrical supply operable to supply a second current whilst the semiconductor switching means are in a state of conduction, the second current being such as to cause substantially zero current to flow through the primary switch, such that the primary switch can then be opened under a condition of substantially zero load current. A corresponding method of operating a mechanical switch in such a device is also provided.The disclosure further provides a controllable electrical supply comprising: an electrical source; an amplifier having two output terminals and comprising a plurality of semiconductor devices; and control logic arranged to operate the amplifier such that it can selectively present both current and voltage source behaviour at the terminals.
  • Conference paper
    Ahmadi AR, Green TC, 2010,

    Voltage versus Power Factor Regulation for enhancement of renewable generation capacity

    The connection of Distributed Generators (DGs) to distribution network creates technical concerns for Distribution Network Operators (DNOs) which primarily include power flow management, loss increase and voltage management problems. Active Network Management (ANM) system provides monitoring and control of the distribution network as well as providing the infrastructure and technology for full integration of DGs to the distribution network. Optimal Power Flow (OPF) is a valuable tool in providing optimal control solutions for active network management system applications. In this paper, Terminal Voltage Regulator Mode (TVRM) and fixed Power Factor Regulation Mode (PFRM) were incorporated in the main optimisation routine to extract the maximum real power output capacity. The main contribution was to test different droop characteristics including one with local voltage regulator dead-bands associated to a particular DG. The DG operation methods of PFRM and TVRM are then compared together. Numerical result obtained from tests on two U.K. representative distribution networks show that TVRM has the potential in offering more capacity exploitation and improving network flexibility for additional DG connection.
  • Conference paper
    Rogers DJ, Green TC, 2010,

    Zero-current zero-voltage switching for on-load tap changers

    We present a new on-load tap changer (OLTC) design that provides the traditional advantages of the semiconductor-assisted OLTC over the classic, mechanical OLTC. The design provides zero-current, zero-voltage operation of both diverter switches at all times, eliminating contact wear due to arcing. The design of the diverter sub-circuit is discussed, including the introduction of a voltage source and corresponding control loop that provides the necessary shunt current or voltage to create the desired zero conditions in the diverter switches. The design differs from existing semiconductor-assisted OLTC systems by the fact that the semiconductor portion of the system is connected in a purely shunt configuration to the main current path. Under normal conditions the load current flows only in the selector and diverter switches making the system very low loss.
  • Journal article
    Moreno R, Strbac G, Porrua F, Mocarquer S, Bezerra Bet al., 2010,

    Making Room for the Boom

    , IEEE POWER & ENERGY MAGAZINE, Vol: 8, Pages: 36-46, ISSN: 1540-7977
  • Journal article
    Jones BL, Kerrigan EC, 2010,

    When is the discretization of a spatially distributed system good enough for control?

    , AUTOMATICA, Vol: 46, Pages: 1462-1468, ISSN: 0005-1098
  • Journal article
    Jabr RA, Pal BC, Martins N, 2010,

    A Sequential Conic Programming Approach for the Coordinated and Robust Design of Power System Stabilizers

    , IEEE Transactions on Power Systems, Vol: 25, Pages: 1627-1637

    This paper shows that conic programming is an effective tool to solve robust power system stabilizer (PSS) design problems, namely coordinated gain tuning and coordinated phase and gain tuning. Design robustness is achieved by simultaneously considering several operating scenarios. The method is implemented through a sequence of conic programming runs that define a multivariable root locus along which the eigenvalues move. Specifically, the eigenvalues corresponding to the unstable and poorly damped modes are moved to a conic sector in the left half of the s-plane, whereas the eigenvalues corresponding to the well damped modes are constrained to stay within the boundaries of this conic sector. At each step of the solution, the PSS design parameters are restricted in a trust-region such that the computation of the eigenvalue shift based on the residue method holds valid. The proposed method is demonstrated on a 68-bus test system with nine different operating conditions. Comparisons are carried out between conic programming implementations for PSS coordinated gain tuning and for simultaneous tuning of gain and phase characteristics
  • Journal article
    Singh R, Manitsas E, Pal BC, Strbac Get al., 2010,

    A Recursive Bayesian Approach for Identification of Network Configuration Changes in Distribution System State Estimation

    , IEEE Transactions on Power Systems, Vol: 25, Pages: 1329-1336

    This paper deals with the identification of network configuration changes in distribution system state estimation (DSSE). The models of critical network configurations are stored in the form of a model bank. A recursive Bayesian approach which utilizes the output of the state estimation function of each model in the bank is used to identify the correct configuration of the network. The concept is demonstrated on a part of the U.K. Generic Distribution System (UKGDS) model.
  • Journal article
    Jabr RA, Pal BC, Martins N, JCR Fet al., 2010,

    Robust and coordinated tuning of power system stabiliser gains using sequential linear programming

    , IET Generation, Transmission and Distribution, Vol: 4, Pages: 893-904, ISSN: 1751-8687

    This study presents a linear programming (LP)-based multivariable root locus following technique for coordinating the gain settings of power system stabilisers (PSSs). The stabiliser robustness is accounted for in the design problem by simultaneously considering the state-space representations and multivariable root loci corresponding to different operating scenarios. The proposed technique computes a curve in the PSS gain parameter space such that when the PSS gains move along this curve to their optimal values, the branches of the corresponding multivariable root loci terminate at satisfactory points in the complex plane. The curve in the gain parameter space is computed via a linear program that successively minimises the Euclidean distance between the unsatisfactory and satisfactory eigenvalue locations. The design method is demonstrated on a 39-bus test system with 14 operating scenarios. A comparison is carried out between the coordination results of two PSS structures, one involving two phase-lead blocks and the other comprised of two phase-lead blocks and a phase-lag block.
  • Journal article
    Sassano M, Carnevale D, Astolfi A, 2010,

    Observer design for range and orientation identification

    , AUTOMATICA, Vol: 46, Pages: 1369-1375, ISSN: 0005-1098
  • Journal article
    Angeli D, 2010,

    A Modular Criterion for Persistence of Chemical Reaction Networks

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 55, Pages: 1674-1679, ISSN: 0018-9286
  • Journal article
    Hui SYR, Liu X, 2010,

    Semiconductor transformers

    , ELECTRONICS LETTERS, Vol: 46, Pages: 947-U110, ISSN: 0013-5194
  • Software
    E J Van Wyk, P Falugi, E C Kerrigan, 2010,

    ICLOCS

    Solves nonlinear optimal control problems subject to constraints.
  • Journal article
    Chaudhuri NR, Chaudhuri B, Ray S, Majumder Ret al., 2010,

    Wide-area phasor power oscillation damping controller: a new approach to handling time-varying signal latency

    , IET GENERATION TRANSMISSION & DISTRIBUTION, Vol: 4, Pages: 620-630, ISSN: 1751-8687
  • Journal article
    Carnevale D, Karagiannis D, Astolfi A, 2010,

    A Condition for Certainty Equivalence Output Feedback Stabilization of Nonlinear Systems

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 55, Pages: 1180-1185, ISSN: 0018-9286
  • Conference paper
    Howey DA, Holmes AS, Pullen KR, 2010,

    Prediction and measurement of heat transfer in air-cooled disc-type electrical machines

    , 5th IET International Conference on Power Electronics, Machines and Drives (PEMD 2010), Publisher: IET

    Accurate thermal analysis of axial flux permanent magnet (AFPM) machines is crucial in predicting maximum power output. Stator convective heat transfer is one of the most important and least investigated heat transfer mechanisms and is the focus of this paper. Experimental measurements were undertaken using a thin-film electrical heating method, providing radially resolved steady state heat transfer data from an experimental rotor-stator system designed as a geometric mockup of a through-flow ventilated AFPM machine. The measurements are compared with computational fluid dynamics (CFD) simulations using both 2D axisymmetric and 3D models. These were found to give a conservative estimate of heat transfer, with inaccuracies near the edge and in the transitional flow regime. Predicted stator heat transfer was found to be relatively insensitive to the choice of turbulence model and the SST model was used for most of the simulations.
  • Journal article
    Ledyaev YS, Vinter RB, 2010,

    Discontinuous feedback in nonlinear control: Stabilization under persistent disturbances

    , PROCEEDINGS OF THE STEKLOV INSTITUTE OF MATHEMATICS, Vol: 268, Pages: 222-241, ISSN: 0081-5438
  • Journal article
    Parisini T, 2010,

    Control Systems Technology: Towards a Systems-of-Systems Perspective?

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 18, Pages: 249-250, ISSN: 1063-6536
  • Journal article
    Lee CK, Hui SYR, 2010,

    Experimental comparison of traditional and alternating winding method for planar spiral inductor

    , ELECTRONICS LETTERS, Vol: 46, Pages: 238-U71, ISSN: 0013-5194
  • Journal article
    Falugi P, Olaru S, Dumur D, 2010,

    Robust Multi-model Predictive Control Using LMIs

    , INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS, Vol: 8, Pages: 169-175, ISSN: 1598-6446
  • Journal article
    Zhang X, Polycarpou MM, Parisini T, 2010,

    Fault diagnosis of a class of nonlinear uncertain systems with Lipschitz nonlinearities using adaptive estimation

    , AUTOMATICA, Vol: 46, Pages: 290-299, ISSN: 0005-1098
  • Journal article
    Lee J, Hong J, Nam K, Ortega R, Praly L, Astolfi Aet al., 2010,

    Sensorless Control of Surface-Mount Permanent-Magnet Synchronous Motors Based on a Nonlinear Observer

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 25, Pages: 290-297, ISSN: 0885-8993
  • Journal article
    Angeli D, Rawlings JB, 2010,

    Receding Horizon cost optimization and control for nonlinear plants

    , IFAC Proceedings Volumes IFAC Papersonline, Vol: 43, Pages: 1217-1223, ISSN: 1474-6670

    Control performance and cost optimization can be conflicting goals in the management of industrial processes. Even when optimal or optimization-based control synthesis tools are applied, the economic cost associated with plant operation is often only optimized according to static criteria that pick, among all feasible equilibria, those associated to minimal cost. This note collects and illustrates some recent advances in Receding Horizon optimization of nonlinear systems that allow to simultaneously optimize transient and steady-state economic performance. © 2010 IFAC.
  • Conference paper
    Ahmad MI, Jaimoukha IM, Frangos M, 2010,

    Krylov subspace restart scheme for solving large scale Sylvester equations

    , American Control Conference, ACC 2010
  • Conference paper
    Shahzad A, Kerrigan EC, Constantinides GA, 2010,

    A Fast Well-conditioned Interior Point Method for Predictive Control

    , IEEE Control and Decision Conference

    Interior point methods (IPMs) have proven to be an efficient way of solving quadratic programming problems in predictive control. A linear system of equations needs to be solved in each iteration of an IPM. The ill-conditioning of this linear system in the later iterations of the IPM prevents the use of an iterative method in solving the linear system due to a very slow rate of convergence; in some cases the solution never reaches the desired accuracy. In this paper we propose the use of a well-conditioned, approximate linear system, which increases the rate of convergence of the iterative method. The computational advantage is obtained by the use of an inexact Newton method along with the use of novel preconditioners. Numerical results indicate that the computational complexity of our proposed method scales quadratically with the number of states and linearly with the horizon length.
  • Conference paper
    Hasan A, Kerrigan EC, Constantinides GA, 2010,

    An ISS and l-stability Approach to Forward Error Analysis of Iterative Numerical Algorithms

    , IEEE Control and Decision Conference
  • Conference paper
    Mitcheson PD, 2010,

    Energy Harvesting for Human Wearable and Implantable Bio-Sensors

    , IEEE EMBC, Publisher: IEEE, Pages: 3432-3436
  • Journal article
    Singh R, Pal BC, Jabr RA, 2010,

    Distribution System State Estimation Through Gaussian Mixture Model of the Load as Pseudo Measurement

    , IET Generation, Transmission and Distribution, Vol: 4, Pages: 50-59

    This study presents an approach to utilise the loads as pseudo-measurements for the purpose of distribution system state estimation (DSSE). The load probability density function (pdf) in the distribution network shows a number of variations at different nodes and cannot be represented by any specific distribution. The approach presented in this study represents all the load pdfs through the Gaussian mixture model (GMM). The expectation maximisation (EM) algorithm is used to obtain the parameters of the mixture components. The standard weighted least squares (WLS) algorithm utilises these load models as pseudomeasurements. The effectiveness of WLS is assessed through some statistical measures such as bias, consistency and quality of the estimates in a 95-bus generic distribution network model.
  • Journal article
    Coetzee LC, Craig IK, Kerrigan EC, 2010,

    Robust Nonlinear Model Predictive Control of a Run-of-Mine Ore Milling Circuit

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 18, Pages: 222-229, ISSN: 1063-6536
    • Cite
    • Citations: 50
  • Journal article
    Offer GJ, Howey DA, Contestabile M, Clague R, Brandon NPet al., 2010,

    Comparative analysis of battery electric, hydrogen fuel cell and hybrid vehicles in a future sustainable road transport system

    , Energy Policy, Vol: 38, Pages: 24-29

    This paper compares battery electric vehicles (BEV) to hydrogen fuel cell electric vehicles (FCEV) and hydrogen fuel cell plug-in hybrid vehicles (FCHEV). Qualitative comparisons of technologies and infrastructural requirements, and quantitative comparisons of the lifecycle cost of the powertrain over 100,000 mile are undertaken, accounting for capital and fuel costs. A common vehicle platform is assumed. The 2030 scenario is discussed and compared to a conventional gasoline-fuelled internal combustion engine (ICE) powertrain. A comprehensive sensitivity analysis shows that in 2030 FCEVs could achieve lifecycle cost parity with conventional gasoline vehicles. However, both the BEV and FCHEV have significantly lower lifecycle costs. In the 2030 scenario, powertrain lifecycle costs of FCEVs range from $7360 to $22,580, whereas those for BEVs range from $6460 to $11,420 and FCHEVs, from $4310 to $12,540. All vehicle platforms exhibit significant cost sensitivity to powertrain capital cost. The BEV and FCHEV are relatively insensitive to electricity costs but the FCHEV and FCV are sensitive to hydrogen cost. The BEV and FCHEV are reasonably similar in lifecycle cost and one may offer an advantage over the other depending on driving patterns. A key conclusion is that the best path for future development of FCEVs is the FCHEV.
  • Journal article
    Astolfi A, Ortega R, Venkatraman A, 2010,

    A globally exponentially convergent immersion and invariance speed observer for mechanical systems with non-holonomic constraints

    , AUTOMATICA, Vol: 46, Pages: 182-189, ISSN: 0005-1098

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