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  • Conference paper
    Clark JMC, Vinter RB, Yaqoob MM, 2005,

    The Shifted Rayleigh Filter for Bearings Only Tracking
  • Conference paper
    Vinter R B, 2005,

    The Role of Metric Regularity in State Constrained Optimal Control
  • Conference paper
    Angeli D, Astolfi A, 2005,

    A Tight Small-Gain Theorem for Not Necessarily ISS Systems

    , Pages: 5427-5431
  • Book chapter
    Karagiannis D, Astolfi A, Ortega R, 2005,

    Nonlinear adaptive stabilization via system immersion: control design and applications

    , Advanced topics in control systems theory, Editors: Lamnabhi-Lagarrigue, Loria, Panteley, Publisher: Springer Verlag, Pages: 1-21
  • Journal article
    Cao GY, Hill DJ, Hui R, Chen Cet al., 2005,

    A new theory to aid in judging power system transient stability

    , Power System Technology, Vol: 29, Pages: 40-44, ISSN: 1000-3673

    Inspired by the concept of trajectory sensitivity of dynamic systems and based on the knowledge of domain of attraction and asymptotic stability of dynamic systems, the authors proposed a new principle that could be used to aid in judging power system transient stability. It could be known from this principle that whether an initial point lied in the domain of attraction of an equilibrium point of autonomous nonlinear dynamic systems or not was able to be decided by the asymptotic stability of equilibrium point of its linearized system, which had a lot of 'good' properties that could be exploited. A positive constant was defined as the acceleration factor of the linear system, which could accelerate the convergence or divergence of this system so as to decrease the simulation time of the power system dynamics for transient stability analysis. Results of applying the proposed principle to single-machine infinitive-bus system and multi-machine system show that this principle is correct and feasible.
  • Journal article
    Chan SSM, Chung HSH, Hui SY, 2005,

    Design and analysis of an IC-less self-oscillating series resonant inverter for dimmable electronic ballasts

    , IEEE Transactions on Power Electronics, Vol: 20, Pages: 1450-1458, ISSN: 0885-8993

    This paper presents a low-cost solution of converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable de current source from the resonant inductor in the resonant tank to control the operating point of the saturable transformers for driving the switches in the inverter. The overall implementation does not require any integrated circuit. A 17-W prototype has been built and studied. Theoretical predictions have been verified with experimental results. The lamp can be dimmed down to 10% of the full power. © 2005 IEEE.
  • Journal article
    Lee STS, Chung HSH, Hui SY, 2005,

    TRIAC dimmable ballast with power equalization

    , IEEE Transactions on Power Electronics, Vol: 20, Pages: 1441-1449, ISSN: 0885-8993

    A two-stage, two-wire TRIAC dimmable electronic ballast for fluorescent lamps is presented in this paper. It is constructed by using a flyback converter as the input power factor corrector to supply a half-bridge series-resonant parallel-loaded inverter to ballast the lamp. The flyback converter is operated in discontinuous conduction mode so that the filtered input current profile is the same as the TRIAC-controlled voltage waveform. The switches in the inverter are switched at a constant frequency slightly higher than the resonant frequency of the resonant tank. Based on the constant average input current characteristics of the inverter, the dimming operation is simply achieved by pulsewidth modulation control of the magnitude of the flyback converter output voltage. No synchronization network is required between the input and output stages. In addition, a linear power equalization scheme is developed so that the dc-link voltage (and hence the lamp power) is in a linear relationship with the firing angle of the TRIAC. The average output voltage of the dimmer controls the equalized flyback converter output voltage. Modeling, analysis, and design of the ballast will be described. A prototype was implemented to verify the experimental measurements with the theoretical predictions. © 2005 IEEE.
  • Journal article
    Yan W, Hui SY, 2005,

    An analysis into the dimming control and characteristic of discharge lamps

    , IEEE Transactions on Power Electronics, Vol: 20, Pages: 1432-1440, ISSN: 0885-8993

    This paper provides some qualitative insights into, and a quantitative analysis of, the interrelationship between the ballast circuit parameters and the physical processes inside the lamp arc under dimming conditions. Qualitative explanation is supported by experimental observations on the dimming characteristics of fluorescent and high-intensity-discharge (HID) lamps. This understanding enables engineers to choose the right combination of dimming technique and electronic ballast topology for different types of discharge lamps. Verified by experiments, the fundamental approximation technique is used to characterize the frequency-control and voltage-control dimming technique for series-loaded and parallel-load resonant circuits. © 2005 IEEE.
  • Journal article
    Yan W, Hui SYR, 2005,

    A universal PSpice model for HID lamps

    , IEEE Transactions on Industry Applications, Vol: 41, Pages: 1594-1602, ISSN: 0093-9994

    Based on the physical laws of plasma discharge, a simplified but accurate model that can be easily implemented in PSpice is presented. This model does not require data from lamp manufacturers. Its parameters can be determined from external measurements of the lamps under low-frequency operation only, but the model is accurate for both low- and high-frequency operations. The high intensity discharge (HID) lamp model has been tested in a 50-W mercury lamp and a 35-W metal-halide (MH) lamp, and the simulated results have been compared with measurements. Experimental results have confirmed that the model is accurate for a wide frequency range. © 2005 IEEE.
  • Journal article
    Laila DS, Astolfi A, 2005,

    Input-to-state stability for discrete-time time-varying systems with applications to robust stabilization of systems in power form

    , AUTOMATICA, Vol: 41, Pages: 1891-1903, ISSN: 0005-1098
  • Report
    Mitcheson PD, 2005,

    Analysis and Optimisation of Energy-Harvesting Micro-Generator Systems

    , PhD Thesis, Imperial College London
  • Journal article
    Majumder R, Chaudhuri B, El-Zobaidi H, Pal BC, Jaimoukha IMet al., 2005,

    LMI approach to normalised H-infinity loop-shaping design of power system damping controllers

    , IEE P-GENER TRANSM D, Vol: 152, Pages: 952-960, ISSN: 1350-2360

    Application of the normalised R., loop-shaping technique for design and simplification of damping controllers in the LMI framework is illustrated. A linearised model of the power system is pre- and post-compensated using the loop-shaping approach. The problem of robust stabilisation of a normalised coprime factor plant description is translated to a generalised H-infinity problem. The solution is sought numerically using LMIs with additional pole-placement constraints. This ensures that the time-domain specifications are met besides robust stabilisation.
  • Journal article
    Astolfi A, Colaneri P, 2005,

    Hankel/Toeplitz matrices and the static output feedback stabilization problem

    , MATHEMATICS OF CONTROL SIGNALS AND SYSTEMS, Vol: 17, Pages: 231-268, ISSN: 0932-4194
  • Journal article
    Cheng D, Astolfi A, Ortega R, 2005,

    On feedback equivalence to port controlled Hamiltonian systems

    , Systems & Control Letters, Vol: 54, Pages: 911-917, ISSN: 0167-6911
  • Journal article
    Astolfi A, Kaliora G, Jiang ZP, 2005,

    Output feedback stabilization and approximate and restricted tracking for a class of cascaded systems

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 50, Pages: 1390-1396, ISSN: 0018-9286
  • Conference paper
    Cao D, Pudjianto D, Grenard S, Strbac Get al., 2005,

    Benefits of active voltage controls in distribution networks
  • Journal article
    Clark JMC, Crisan D, 2005,

    On a robust version of the integral representation formula of nonlinear filtering

    , Probability and Related Fields, Vol: 133, Pages: 43-56
  • Journal article
    Parlos AG, Ji CY, Parisini T, Baglietto M, Atiya AF, Claffy Ket al., 2005,

    Introduction to the Special Issue on Adaptive Learning Systems in Communication Networks

    , IEEE TRANSACTIONS ON NEURAL NETWORKS, Vol: 16, Pages: 1013-1018, ISSN: 1045-9227
  • Journal article
    Karagiannis D, Jiang ZP, Ortega R, Astolfi Aet al., 2005,

    Output-feedback stabilization of a class of uncertain non-minimum-phase nonlinear systems

    , AUTOMATICA, Vol: 41, Pages: 1609-1615, ISSN: 0005-1098
  • Journal article
    Barabanov N, Ortega R, Astolfi A, 2005,

    Is normalization necessary for stable model reference adaptive control?

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 50, Pages: 1384-1390, ISSN: 0018-9286
  • Journal article
    Qiu DY, Hui SY, Chung HSH, 2005,

    Parameter monitoring of high-frequency electronically operated discharge lamp systems

    , IEEE Transactions on Power Electronics, Vol: 20, Pages: 948-952, ISSN: 0885-8993

    Discharge lamps require high ignition voltage from typically one to several kilovolts for cold-start, but have low onstate voltage of typically 100 V. For discharge arc monitoring purposes, it is difficult or uneconomical to implement voltage sensor to cover such a wide range of voltage. In this paper, a nonintrusive and electrically isolated method, based on the single-sensor principle, is used to derive the system parameters and variables for system monitoring and control purposes. Unlike the traditional resistive potential divider for voltage feedback, the proposed method is nondissipative. Only one coupled winding is used to derive the converter inductor voltage, from which the lamp power, lamp arc resistance and inverter dc link voltage can be accurately derived. The proposal is verified with good agreement between derived values and measurements in an electronic ballast-fluorescent lamp system. The proposal can be useful in applications in which sensing the voltage across the load is either difficult or costly. © 2005 IEEE.
  • Journal article
    Guoyun C, Hill DJ, Hui R, 2005,

    Continuation of local bifurcations for power system differential-algebraic equation stability model

    , IEE Proceedings: Generation, Transmission and Distribution, Vol: 152, Pages: 575-580, ISSN: 1350-2360

    Information about the boundary of local bifurcations is important for utilities to guarantee the secure operation of power systems, and therefore local bifurcation analysis is a useful tool in power systems stability analysis. A new method is presented for calculating the multi-parameter singularity-induced, saddle-node and Hopf bifurcation boundary associated with the parameter-dependent differential-algebraic equations (DAE), which are used to model power systems dynamics. This method is based on the idea of the continuation method, which means that these three kinds of local bifurcations of DAE systems are expressed by appropriate nonlinear algebraic equations, which can be used to track the multi-parameter local bifurcation boundary directly by the continuation method from a known one-parameter local bifurcation point on the boundary, and thus it has the advantage of being a direct method as the continuation method itself inherently contains an iteration procedure during tracking the boundary point by point. Another advantage of this method is that it keeps the DAE form of the mathematical model of power systems and thus preserves the sparsity of the data structure. Several example power systems are used to illustrate the proposed method. © IEE, 2005.
  • Conference paper
    Goulart PJ, Kerrigan EC, 2005,

    Relationships between affine feedback policies for robust control with constraints
  • Conference paper
    Rakovic SV, Mayne DQ, Kerrigan EC, Kouramas KIet al., 2005,

    Optimized robust control invariant sets for constrained linear discrete-time systems
  • Journal article
    Astolfi A, Kaliora G, 2005,

    A geometric characterization of feedforward forms

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 50, Pages: 1016-1021, ISSN: 0018-9286
  • Journal article
    Stark BH, Green TC, 2005,

    A comparison of SOI Power Device Structures in Power Converters for High-Voltage, Low-Charge Electrostatic Micro-Generators

    , IEEE Trans on Electron Devives, Vol: 52, Pages: 1640-1648
  • Conference paper
    Goulart PJ, 2005,

    Relationships Between Affine Feedback Policies for Robust Control with Constraints

    , 16th IFAC World Congress on Automatic Control
  • Conference paper
    Goulart PJ, Kerrigan EC, 2005,

    An efficient decomposition-based formulation for robust control with constraints

    , 16 IFAC World Congress on Automatic Control
  • Journal article
    Mok TK, Liu H, Ni Y, Wu FF, Hui Ret al., 2005,

    Tuning the fuzzy damping controller for UPFC through genetic algorithm with comparison to the gradient descent training

    , International Journal of Electrical Power and Energy Systems, Vol: 27, Pages: 275-283, ISSN: 0142-0615

    The unified power flow controller (UPFC) is the most versatile device in the flexible ac transmission systems (FACTS) which can provide superior power flow and voltage control through its main control. It can also improve power system dynamic performance through its supplementary control. In this paper, a fuzzy supplementary controller is designed for the UPFC to damp tie line power oscillation in the interconnected power systems. The parameters of the fuzzy damping controller (FDC) are optimized using the gradient descent training method and the genetic algorithm, respectively. The UPFC power frequency model, its main and supplementary control block diagrams and the formulation for the FDC parameter optimization are presented. Time simulation on a multi-machine inter-connected power system shows that the two optimization methods converge very well and yield very close FDC parameters and the designed FDC performs well in damping the tie line power oscillation under large disturbances. Computer simulation results also show that the FDC has better robustness under different system operation conditions than its conventional counterpart. © 2004 Elsevier Ltd. All rights reserved.
  • Conference paper
    Hernandez-Aramburo CA, Green TC, Mugniot N, 2005,

    Fuel consumption minimization of a microgrid

    , 39th Annual Meeting of the IEEE-Industry-Applications-Society, Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, Pages: 673-681, ISSN: 0093-9994

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