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  • Journal article
    Lee CK, Zhong WX, Hui SYR, 2012,

    Effects of Magnetic Coupling of Nonadjacent Resonators on Wireless Power Domino-Resonator Systems

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 27, Pages: 1905-1916, ISSN: 0885-8993
  • Journal article
    Ng WM, Lin DY, Hui SY, 2012,

    Design of a Single Ultra-Low-Loss Magnetic Ballast for a Wide Range of T5 High-Efficiency Fluorescent Lamps

    , IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, Vol: 59, Pages: 1849-1858, ISSN: 0278-0046
  • Journal article
    Piplezadeh Y, Chaudhuri B, Green TC, 2012,

    Control Coordination Within a VSC-HVDC Link for Power Oscillation Damping: A Robust Decentralized Approach Using Homotopy

    , IEEE Transactions on Control Systems Technology

    Power oscillations can be damped effectivelythrough modulation of both active and reactive power of a voltage source converter based high voltage direct current link. The challenge, however, is how to coordinate the control action properly at the two ends of the link without using a centralised control scheme, which requires fast communication of control signals to remote actuator (converters) sites. A full centralised controller may result in a closed-loop performance worse than that of an open loop in case of a communication loss of feedback signal(s). Alternatively, with a block-diagonal control structure, the individual control loops are decoupled from each other, which is not only easier to implement in a decentralized way, but also shown to guarantee a certain level of performance. Here, the concept of homotopy is applied to obtain a single block-diagonal controller from a set of full controllers, individually designed to ensure specified closed-loop performance for a set of operating conditions. Simulation studies in DIgSILENT PowerFactory are carried out on two test systems to demonstrate both the robustness and control coordination in a decentralised framework.
  • Journal article
    Jerez JL, Kerrigan EC, Constantinides GA, 2012,

    A sparse and condensed QP formulation for predictive control of LTI systems

    , Automatica, Vol: 48, Pages: 999-1002, ISSN: 1873-2836

    The computational burden that model predictive control (MPC) imposes depends to a large extent on the way the optimal control problem is formulated as an optimization problem. We present a formulation where the input is expressed as an affine function of the state such that the closed-loop dynamics matrix becomes nilpotent. Using this approach and removing the equality constraints leads to a compact and sparse optimization problem to be solved at each sampling instant. The problem can be solved with a cost per interior-point iteration that is linear with respect to the horizon length, when this is bigger than the controllability index of the plant. The computational complexity of existing condensed approaches grow cubically with the horizon length, whereas existing non-condensed and sparse approaches also grow linearly, but with a greater proportionality constant than with the method presented here.
  • Journal article
    Clark JMC, Vinter RB, 2012,

    Stochastic exit time problems arising in process control

    , Stochastics-An International Journal of Probability and Stochastic Processes, Vol: 84, Pages: 667-681, ISSN: 1744-2516

    This paper concerns the problem of controlling a stochastic system, with small noise parameter, to prevent it leaving a safe region of the state space. Such problems arise in flow control and other areas. We consider a formulation of the problem, in which a control is sought, to maximize a cost which is related to the expected exit time, but modified to reduce the probability of an early exit, according to a specified level of risk aversion (‘risk sensitive’ stochastic control). Formally letting the noise parameter tend to zero, we find that the optimal control strategy for this problem coincides with the optimal feedback control strategy for a differential game. We identify a class of differential games arising in this way, the so called decomposable differential games, for which the optimal control strategy can be easily obtained and illustrate the proposed solution technique by applying it to a flow control problem arising in process systems engineering.
  • Conference paper
    Shabbir W, Evangelou SA, Arana C, 2012,

    Series hybrid electric vehicle supervisory control based on off-line efficiency optimization

    , 2012 IEEE International Electric Vehicle Conference
  • Patent
    Brandon NPB, Mitcheson PD, Yufit V, Howey DA, Offer GJet al., 2012,

    Battery Monitoring in Electric Vehicles, Hybrid Electric Vehicles, and other Applications

    , WO/2012/025706
  • Patent
    Evangelou SA, Dini D, De Meerschman O, Tocatlian A, Kneip C, Palas Cet al., 2012,

    Variable-geometry suspension apparatus and vehicle comprising such apparatus
  • Journal article
    Parisini T, 2012,

    Untitled

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 20, Pages: 289-290, ISSN: 1063-6536
  • Journal article
    Howey DA, Childs PRN, Holmes AS, 2012,

    Air-gap convection in rotating electrical machines

    , IEEE Transactions on Industrial Electronics, Vol: 59, Pages: 1367-1375, ISSN: 0278-0046

    This paper reviews convective heat transfer within the air-gap of both cylindrical and disc geometry rotating electrical machines, including worked examples relevant to fractional horsepower electrical machines. Thermal analysis of electrical machines is important because torque density is limited by maximum temperature. Knowledge of surface convective heat transfer coefficients is necessary for accurate thermal modelling for example using lumped parameter models. There exists a wide body of relevant literature, but much of it has traditionally been in other application areas, dominated by mechanical engineers, such as gas turbine design. Particular attention is therefore given to the explanation of the relevant non-dimensional parameters, and to the presentation of measured convective heat transfer correlations for a wide variety of situations from laminar to turbulent flow at small and large gap sizes for both radial flux and axial flux electrical machines.
  • Journal article
    Chen W, Hui SYR, 2012,

    Elimination of an Electrolytic Capacitor in AC/DC Light-Emitting Diode (LED) Driver With High Input Power Factor and Constant Output Current

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 27, Pages: 1598-1607, ISSN: 0885-8993
  • Journal article
    Manitsas E, Singh R, Pal BC, Strbac Get al., 2012,

    Distribution System State Estimation using an Artificial Neural Network Approach for Pseudo Measurement Modeling

    , IEEE Transactions on Power Systems, Vol: 27, Pages: 1888-1896-1896, ISSN: 0885-8950

    This paper presents an alternative approach topseudo measurement modeling in the context of distributionsystem state estimation (DSSE). In the proposed approach pseudomeasurements are generated from a few real measurements usingartificial neural networks (ANNs) in conjunction with typicalload profiles. The error associated with the generated pseudomeasurements is made suitable for use in the weighted leastsquares (WLS) state estimation by decomposition into severalcomponents through the Gaussian mixture model (GMM). Theeffect of ANN-based pseudo measurement modeling on thequality of state estimation is demonstrated on a 95-bus sectionof the U.K. generic distribution system (UKGDS) model
  • Patent
    Green TC, Merlin MMC, Okaeme N, Trainer DRet al., 2012,

    A Method of Voltage Source Converter Cell Voltage Balancing using Circulating Current

    , WO/2012/013248
  • Journal article
    Jabr RA, Singh R, Pal BC, 2012,

    Minimum Loss Network Reconfiguration Using Mixed-Integer Convex Programming

    , IEEE Transactions on Power Systems, Vol: 27, Pages: 1106-1115, ISSN: 0885-8950

    This paper proposes a mixed-integer conic programmingformulation for the minimum loss distribution network reconfigurationproblem. This formulation has two features: first,it employs a convex representation of the network model whichis based on the conic quadratic format of the power flow equationsand second, it optimizes the exact value of the network losses.The use of a convex model in terms of the continuous variables isparticularly important because it ensures that an optimal solutionobtained by a branch-and-cut algorithm for mixed-integer conicprogramming is global. In addition, good quality solutions with arelaxed optimality gap can be very efficiently obtained. A polyhedralapproximation which is amenable to solution via more widelyavailable mixed-integer linear programming software is also presented.Numerical results on practical test networks including distributedgeneration show that mixed-integer convex optimization is an effective tool for network reconfiguration.
  • Journal article
    Jabr RA, Martins N, Pal BC, Karaki Set al., 2012,

    Contingency Constrained VAr Planning Using Penalty Successive Conic Programming

    , IEEE Transactions on Power Systems, Vol: 1, Pages: 545-553, ISSN: 0885-8950

    This paper presents a new method for VAr planning under multiple operating scenarios, optimizing sizes and locations of new reactive compensation equipment to ensure that both the system voltage profile and voltage stability requirements are met. The approach is based on ${mbi L}_{1}$-norm regularization for finding a solution with minimum VAr installation sites and on the ${mbi L}_{2}$-norm penalty function for satisfying the multiple state constraints. The ${mbi L}_{2}$-norm penalty function is exact in the sense that a finite penalty parameter is required to establish equivalence with the VAr planning problem, thus avoiding numerical ill-conditioning. The solution is obtained from a successive conic programming algorithm which makes use of adaptive trust-region control. The results of the new method are compared with those of an optimal power flow-based program for VAr planning.
  • Journal article
    Bell KWR, Fenton B, Griffiths H, Pal BC, McDonald JRet al., 2012,

    Attracting Graduates to Power Engineering in the U.K.: Successful University and Industry Collaboration

    , IEEE Transactions on Power Systems, Vol: 1, Pages: 450-457, ISSN: 0885-8950

    The power industry in many parts of the industrialized world faces major challenges over the next two decades to renew ageing networks, accommodate new generation, especially renewables, and make grid operation “smarter”. This requires increasing numbers of professionals, but in many places, the industry faces great losses in personnel and experience as senior engineers retire. As a consequence, the industry needs to recruit a new generation of well-qualified electrical engineering graduates. This paper describes one particular initiative to attract school leavers into engineering and electric power engineering in particular: the U.K.'s “Power Academy”. The main features of the scheme and its success to date are described along with the new challenges and various issues that remain to be addressed. These include the need for “engineering leadership” and career progression for technical specialists. It is argued that companies' continued investment in schemes like the Power Academy is essential to meet the challenges faced by the power industry and to ensure a healthy future supply of professional engineers
  • Patent
    Trainer DR, Crookes RW, Green TC, Merlin MMCet al., 2012,

    Voltage Source Converter with Enhanced DC Fault Response

    , WO/2012/013248
  • Journal article
    Moreno R, Pudjianto D, Strbac G, 2012,

    Integrated reliability and cost-benefit-based standards for transmission network operation

    , PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART O-JOURNAL OF RISK AND RELIABILITY, Vol: 226, Pages: 75-87, ISSN: 1748-006X
  • Journal article
    Sturt A, Strbac G, 2012,

    Efficient Stochastic Scheduling for Simulation of Wind-Integrated Power Systems

    , IEEE TRANSACTIONS ON POWER SYSTEMS, Vol: 27, Pages: 323-334, ISSN: 0885-8950
  • Journal article
    Sturt A, Strbac G, 2012,

    Value of stochastic reserve policies in low-carbon power systems

    , PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART O-JOURNAL OF RISK AND RELIABILITY, Vol: 226, Pages: 51-64, ISSN: 1748-006X
  • Conference paper
    Hanrahan B, Feldman J, Misra S, Waits C, Mitcheson PD, Ghodssi Ret al., 2012,

    Off-The-Shelf MEMS for Rotary MEMS

    , IEEE MEMS, Publisher: IEEE, ISSN: 1084-6999
  • Journal article
    Caro E, Singh R, Pal BC, Conejo A, Jabr RAet al., 2012,

    An Incremental PMU Placement Method for Power System State Estimation

    , IET Generation Transmission and Distribution, Vol: 6, Pages: 922-929

    This study focuses on the selection of the most effective location of phasor measurement units (PMUs) in the network for the purpose of state estimation. The reduction in the error of the estimated states, that is, the quality improvement of the estimate, is the objective used to select the most appropriate allocation of PMUs. The concept of participation of various states into the uncertainty of the error is applied to identify the most important states influencing the estimated errors. Unlike other methods, the proposed technique considers all the elements of the state error covariance matrix and therefore addresses the impact of correlations between the errors. The effectiveness of the method has been demonstrated on the standard IEEE 14-bus and IEEE 57-bus system models. The comparison of performance with other existing measurement placement techniques targeting the same objective reflects the effectiveness of the participation factor-based approach.
  • Journal article
    Kunjumuhhamed LP, Singh R, Pal BC, 2012,

    Robust Signal Selection for Damping Inter-area Oscillations

    , IET Generation Transmission and Distribution, Vol: 6, Pages: 404-416, ISSN: 1751-8687

    This study reports an approach of selecting effective feedback signal to damp out electromechanical oscillations in the power system under unpredictable supply and demand situation. The idea of minimum variance of the modal residue has been utilised to select a signal which is very effective over a large number of operating conditions. A minimal variation of residue results in minimal deviation in damping performance from the desired level. The effectiveness of the method is demonstrated in a 16-machine, 68-bus NETS-NYPS test system and 46-machine, 190-bus practical Mexican interconnected system models.
  • Journal article
    Simfukwe D, Pal BC, Jabr RA, Martins Net al., 2012,

    Robust and Low Order Design of FACTS and Power System Stabilizers for Oscillations Damping

    , IET Generation Transmission and Distribution, Vol: 6, Pages: 445-452, ISSN: 1751-8687

    The study presents a method for the coordinated design of low-order robust controllers for stabilising power system oscillations. The design uses conic programming to shift under-damped or unstable modes into a region of sufficient damping of the complex plane and involves two stages. The first stage is a phase compensation design that accounts for multiple operating conditions with flexible AC transmission systems (FACTS) and power system stabilisers (PSS), unlike our earlier approach involving PSS only. The second stage is gain tuning. This is done effectively in a coordinated way using conic programming. An example demonstrates the method's ability to design coordinated FACTS and PSS controllers resulting in damping oscillations over all given operating conditions of the power system with very simple and low-order control structure.
  • Conference paper
    Mylvaganam T, Fobelets K, Jaimoukha I, 2012,

    Optimal Design of Nanowire Array Based Thermocouple

    , 9th European Conference on Thermoelectrics (ECT), Publisher: AMER INST PHYSICS, Pages: 17-20, ISSN: 0094-243X
  • Book chapter
    Gross R, Heptonstall P, Leach M, Skea J, Anderson D, Green Tet al., 2012,

    The uk energy research centre review of the costs and impacts of intermittency

    , Renewable Electricity and the Grid: The Challenge of Variability, Pages: 73-94
  • Book chapter
    Silva V, Stanojevic V, Aunedi M, Pudjianto D, Strbac Get al., 2012,

    Smart domestic appliances as enabling technology for demand-side integration: Modelling, value and drivers

    , The Future of Electricity Demand: Customers, Citizens and Loads, Pages: 243-281

    Introduction: Decarbonization of future electricity systems requires a significant proportion of electricity consumption to be supplied from nuclear, carbon capture and storage (CCS) plant and renewable sources. Since nuclear and CCS plant are less flexible than, for instance, natural gas-fired combined cycle plants, and renewable sources such as wind, solar and tidal are intermittent, this creates serious challenges to the way the current system is operated. In order to ensure that the system is capable of maintaining a supply and demand balance, the reduction in generation flexibility as a result of incorporating more low-carbon generation technologies has to be balanced with an increase in flexibility from demand. Consequently demand-side flexibility needs to be developed and smart domestic appliances can play an important role (IEA, 2008). In order to gain insight and understanding of the role and value of smart appliances, comprehensive studies of its economic value are required. Such analysis needs to consider relevant parameters such as consumers' behaviour and acceptance, appliance technology and future scenarios of power-system development regarding flexibility of generation and network capacity. This chapter presents a framework to assess the value of smart appliances, as flexible demand, to increase system flexibility and to provide new sources of ancillary services. The increased flexibility will improve system efficiency, reduce operating costs and carbon emissions, and increase utilization of renewable sources; from these benefits the value of smart appliances will be derived. However, any decrease in the value of energy services received as a result of, for instance, inconvenience caused by curtailment or rescheduling of consumption should, in theory, be deducted from such benefits. At the core of the framework is a model that simulates annual system operation, scheduling simultaneously generation and smart appliances, in order to minimize system oper
  • Conference paper
    Boem F, Ferrari RMG, Parisini T, Polycarpou MMet al., 2012,

    Distributed fault diagnosis for input-output continuous-time nonlinear systems

    , Pages: 1089-1094, ISSN: 1474-6670

    In this paper, new results on distributed fault diagnosis of continuous-time nonlinear systems with partial state measurements are proposed. Following an overlapping decomposition framework, the dynamics of a nonlinear uncertain large-scale dynamical systems is described as the interconnection of several subsystems. Each subsystem is monitored by its own Local Fault Diagnoser, based on a set of local estimators. A consensus-based protocol is used to improve the detectability and the isolability of faults affecting variables shared among different subsystems because of the overlapping decomposition. A sufficient condition assuring the convergence of the estimation errors is derived. Time-varying threshold functions guaranteeing no false-positive alarms and theoretical results containing detectability and isolability conditions are presented. © 2012 IFAC.
  • Journal article
    Hartley EN, Jerez JL, Suardi A, Maciejowski JM, Kerrigan EC, Constantinides GAet al., 2012,

    Predictive control of a Boeing 747 aircraft using an FPGA

    , IFAC Proceedings Volumes (IFAC-PapersOnline), Vol: 4, Pages: 80-85, ISSN: 1474-6670

    New embedded predictive control applications call for more eficient ways of solving quadratic programs (QPs) in order to meet demanding real-time, power and cost requirements. A single precision QP-on-a-chip controller is proposed, implemented in afield-programmable gate array (FPGA) with an iterative linear solver at its core. A novel offline scaling procedure is introduced to aid the convergence of the reduced precision solver. The feasibility of the proposed approach is demonstrated with a real-time hardware-in-the-loop (HIL) experimental setup where an ML605 FPGA board controls a nonlinear model of a Boeing 747 aircraft running on a desktop PC through an Ethernet link. Simulations show that the quality of the closed-loop control and accuracy of individual solutions is competitive with a conventional double precision controller solving linear systems using a Riccati recursion. © 2012 IFAC.
  • Journal article
    Zhong WX, Hui SY, Ho WC, Liu Xet al., 2012,

    Using Self-Driven AC-DC Synchronous Rectifier as a Direct Replacement for Traditional Power Diode Rectifier

    , IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, Vol: 59, Pages: 392-401, ISSN: 0278-0046

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