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  • Journal article
    Leung KKS, Chung HSH, Hui SYR, 2003,

    Use of state trajectory prediction in hysteresis control for achieving fast transient response of the buck converter

    , Proceedings - IEEE International Symposium on Circuits and Systems, Vol: 3, ISSN: 0271-4310

    A dynamic hysteresis control of the buck converter for achieving high slew-rate response to disturbances is proposed. The hysteresis band is derived from the output capacitor current that predicts the output voltage magnitude after a hypothesized switching action. Four switching criteria are formulated to dictate the state of the main switch. The output voltage can revert to the steady state in two switching actions after a large-signal disturbance. The technique is verified with the experimental results of a 50W buck converter.

  • Journal article
    Valtolina E, Astolfi A, 2003,

    Local robust regulation of chained systems

    , SYSTEMS & CONTROL LETTERS, Vol: 49, Pages: 231-238, ISSN: 0167-6911
  • Journal article
    Yan W, Hui SYR, Chung H, 2003,

    Nonlinear high-intensity discharge lamp model including a dynamic electrode voltage drop

    , IEE Proceedings: Science, Measurement and Technology, Vol: 150, Pages: 161-167, ISSN: 1350-2344

    Based on the physical laws of plasma arc discharge, an accurate nonlinear dynamic high-intensity discharge (HID) lamp model that includes the dynamic electrode voltage drop equation has been developed. The physical model includes the hysteresis effect in the high, frequency V-I characteristic caused by the physical process of electrode regions and can predict lamp terminal characteristics accurately over a wide frequency range. The key advantage of the model is that all parameters can be obtained from typical electrical terminal measurements of the HID lamps without using information that is either unavailable from lamp manufacturers or difficult to measure practically. Simulated and measured results have been used to verify the model. The proposed model provides a powerful tool for simulating the electrical behaviour of the HID lamps and thus can be used as a design tool for electronic ballasts for HID lamps.

  • Journal article
    Lee CK, Leung JSK, Hui SYR, Chung HSHet al., 2003,

    Circuit-level comparison of STATCOM technologies

    , IEEE Transactions on Power Electronics, Vol: 18, Pages: 1084-1092, ISSN: 0885-8993

    This paper performs a comprehensive circuit-level evaluation of four modern STATCOM systems, namely true-48-pulse and quasi-48-pulse STATCOMs, cascade multilevel and binary multilevel inverters. The comparison is based on a number of factors including circuit topology, harmonic distortion, system losses, GTO quantities, their specific applications, and other considerations. The theoretical results are verified by simulation with the use of MATLAB-Simulink Power System Blockset.

  • Journal article
    Qiu DY, Yip SC, Chung HSH, Hui SYRet al., 2003,

    On the use of current sensors for the control of power converters

    , IEEE Transactions on Power Electronics, Vol: 18, Pages: 1047-1055, ISSN: 0885-8993

    This paper describes the use of current sensors for the control of power converters. No voltage sensor is required in the whole system. The sensed current and the rate of change of the inductor current in different circuit topologies are used to determine the input and output voltages of the converters, and for current programming and maximum current protection. Apart from reducing the number of sensors, the proposed method provides inherent electrical isolation between the power conversion stage and the controller and lessens noise-coupling problems. The proposed technique is illustrated with a current-programmed dc/dc boost regulator with feedforward and feedback control. The regulator's steady state and transient responses under input source and output load disturbances are presented.

  • Journal article
    Jabr RA, Pal BC, 2003,

    Iteratively re-weighted least absolute value method for state estimation

    , IEE P-GENER TRANSM D, Vol: 150, Pages: 385-391, ISSN: 1350-2360

    A modified version of the weighted least absolute value (WLAV) method for the solution of the power system-state-estimation problem is presented. The WLAV method can be seen as minimising a linear objective function subject to a set of nonlinear constraints. The modification is aimed at producing a WLAV estimator that remains insensitive to bad data, even if they are associated with leverage-point measurements. This is achieved by bending the linear objective function, so that the residuals of bad measurements are allowed to grow without incurring much additional cost in the objective function. Consequently, the optimisation procedure would find an optimal solution where the residuals of all bad measurements are nonzero. The optimisation is carried out via sequential linear programming. It is shown that each linear program corresponds to a linearised WLAV problem with weights adjusted automatically during the iterations. To ensure fast execution time, the linear program is solved using a homogeneous interior-point method. Computational results show that the proposed method can identify bad data in leverage points.

  • Conference paper
    Chaudhuri B, Pal BC, Zolotas AC, Jaimoukha IM, Green TCet al., 2003,

    Mixed-Sensitivity Approach to H-infinity Control of Power System Oscillations Employing Multiple FACTS Devices

  • Journal article
    Antonelli R, Harmand J, Steyer JP, Astolfi Aet al., 2003,

    Set-point regulation of an anaerobic digestion process with bounded output feedback

    , IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, Vol: 11, Pages: 495-504, ISSN: 1063-6536
  • Conference paper
    Chaudhuri B, Green TC, Jaimoukha IM, Pal BC, Zolotas AC, Chaudhuri B, Green TC, Jaimoukha IM, Pal BC, Zolotas AC, Chaudhuri B, Green TC, Jaimoukha IM, Pal BC, Zolotas AC, Chaudhuri B, Green TC, Jaimoukha IM, Pal BC, Zolotas AC, Chaudhuri B, Pal BC, Zolotas AC, Jaimoukha IM, Green TCet al., 2003,

    Mixed-sensitivity approach to h(infinity) control of power system oscillations employing multiple facts devices

    , General meeting of IEEE Power Engineering Society, Toronto, Canada, Publisher: IEEE, Pages: 2348-2348
  • Journal article
    Ortega R, Hsu L, Astolfi A, 2003,

    Immersion and invariance adaptive control of linear multivariable systems

    , SYSTEMS & CONTROL LETTERS, Vol: 49, Pages: 37-47, ISSN: 0167-6911
  • Journal article
    Chung HSH, Tse KK, Ron Hui SY, Mok CM, Ho MTet al., 2003,

    A novel maximum power point tracking technique for solar panels using a SEPIC or Cuk converter

    , IEEE Transactions on Power Electronics, Vol: 18, Pages: 717-724, ISSN: 0885-8993

    A novel technique for efficiently extracting the maximum output power from a solar panel under varying meteorological conditions is presented. The methodology is based on connecting a pulse-width-modulated (PWM) dc/dc SEPIC or Cuk converter between a solar panel and a load or battery bus. The converter operates in discontinuous capacitor voltage mode whilst its input current is continuous. By modulating a small-signal sinusoidal perturbation into the duty cycle of the main switch and comparing the maximum variation in the input voltage and the voltage stress of the main switch, the maximum power point (MPP) of the panel can be located. The nominal duty cycle of the main switch in the converter is adjusted to a value, so that the input resistance of the converter is equal to the equivalent output resistance of the solar panel at the MPP. This approach ensures maximum power transfer under all conditions without using microprocessors for calculation. Detailed mathematical derivations of the MPP tracking technique are included. The tracking capability of the proposed technique has been verified experimentally with a 10-W solar panel at different insolation (incident solar radiation) levels and under large-signal insolation level changes.

  • Journal article
    Karagiannis D, Astolfi A, Ortega R, 2003,

    Two results for adaptive output feedback stabilization of nonlinear systems

    , AUTOMATICA, Vol: 39, Pages: 857-866, ISSN: 0005-1098
  • Conference paper
    Chisci L, Falugi P, Zappa G, 2003,

    Tracking of piecewise constant references for constrained nonlinear systems

    , Pages: 886-891

    The paper addresses tracking of a piecewise constant reference for a nonlinear system subject to control and/or state constraints. The proposed controller, called dual-mode, extends to the nonlinear case an approach formerly introduced for linear systems. The dual-mode controller is based on the knowledge of the set of feasible state-setpoint pairs and operates in two different modes: as a regulator if the current state is feasible for the desired set-point, or attempts to recover feasibility as quickly as possible whenever feasibility is lost due to a set-point change. The difficulty of constructing the feasibility set in the state-setpoint space for a nonlinear system is overcome by embedding the original system into a family of uncertain (polytopic) linear systems.

  • Journal article
    Astolfi A, Ortega R, 2003,

    Immersion and invariance: A new tool for stabilization and adaptive control of nonlinear systems

    , IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 48, Pages: 590-606, ISSN: 0018-9286
  • Conference paper
    Halikias GD, Jaimoukha IM, 2003,

    Design of infinite impulse response (IIR) filters with almost linear phase characteristics

  • Journal article
    Chisci L, Falugi P, Zappa G, 2003,

    Gain-scheduling MPC of nonlinear systems

    , INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Vol: 13, Pages: 295-308, ISSN: 1049-8923
  • Journal article
    Tse KK, Ng RWM, Chung HSH, Hui SYRet al., 2003,

    An evaluation of the spectral characteristics of switching converters with chaotic carrier-frequency modulation

    , IEEE Transactions on Industrial Electronics, Vol: 50, Pages: 171-182, ISSN: 0278-0046

    This paper presents an evaluation of the spectral characteristics of switching converters with a chaotic carrier-frequency modulation scheme (CCFMS). By incorporating a Chua's circuit (CC) into the pulsewidth modulator for driving the switches, three modulation schemes, including the standard pulsewidth modulation scheme, periodic carrier-frequency modulation scheme, and CCFMS, can be realized with the CC in equilibrium, limit cycle, and chaos, respectively. The property of frequency spreading in CCFMS is studied by using statistical analysis method. The developed model is applied to formulate the power spectral densities of the input current and the output voltage of the three basic dc/dc converters under CCFMS. Theoretical predictions are verified with experimental measurements.

  • Journal article
    Lee STS, Chung HSH, Chen G, Hui SYet al., 2003,

    Use of Chaotic Switching in Electronic Ballasts

    , IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol: E86-A, Pages: 2203-2208, ISSN: 0916-8508

    This paper investigates the use of chaotic pulsewidth modulation (CPWM) scheme for electronic ballasts to eliminate visible striations (appearance of black and white bands along the lamp tube) in fluorescent lamps. As striations can be eliminated by superimposing a small amount of dc current or low frequency ac current to the electrodes to produce composite current waveform through the lamp, the underlying principle of this work is based on the fact that the power spectral density of the lamp current will be rich of low-frequency harmonics at the output of inverters switching with CPWM. Most importantly, the lamp life will not be affected with chaotic switchings, because the lamp current crest factor is found to be similar to the one with standard pulsewidth modulation (PWM) and the lamp current does not have dc component. The effectiveness of eliminating striations is confirmed experimentally with a T8 36W prototype.

  • Journal article
    Hui RSY, 2003,

    Recent developments of planar printed circuit board (pcb) transformer technology

    , HKIE Transactions Hong Kong Institution of Engineers, Vol: 10, Pages: 35-41, ISSN: 1023-697X

    Rapid developments of planar magnetics in recent years have prompted new applications of planar transformers in electronic industry. The low-profi’e features of planar magentics make them attractive in many electronic systems that have stringent thickness requirements. In this article, some recent progress of planar PCB transformers and their applications are described. Comparisons of canventional and pianar transformers are reviewed. New trend of integrated electronic packaging in power electronic systems is briefly discussed. © 2003 Taylor & Francis Group, LLC.

  • Conference paper
    Chisci L, Falugi P, Zappa G, 2003,

    Tracking of piecewise constant references for constrained nonlinear systems

    , Pages: 886-891

    © 2003 EUCA. The paper addresses tracking of a piecewise constant reference for a nonlinear system subject to control and/or state constraints. The proposed controller, called dual-mode, extends to the nonlinear case an approach formerly introduced for linear systems. The dual-mode controller is based on the knowledge of the set of feasible state-setpoint pairs and operates in two different modes: as a regulator if the current state is feasible for the desired set-point, or attempts to recover feasibility as quickly as possible whenever feasibility is lost due to a set-point change. The difficulty of constructing the feasibility set in the state-setpoint space for a nonlinear system is overcome by embedding the original system into a family of uncertain (polytopic) linear systems.

  • Journal article
    Prodanovic M, Green TC, 2003,

    Control and filter design of three-phase inverters for high power quality grid connection

    , IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 18, Pages: 373-380, ISSN: 0885-8993
  • Journal article
    Vellekoop MH, Clark JMC, 2003,

    A Nonlinear Filtering Approach To Changepoint Detection Problems: Direct And Differential-Geometric Methods

    , SIAM Journal on Control and Optimization, Vol: 42, Pages: 469-494
  • Journal article
    Hernandez-Aramburo CA, Green TC, Smith AC, 2003,

    Estimating rotational iron losses in an induction machine

    , IEEE Transactions on Magnetics, Vol: 39, Pages: 3527-3533, ISSN: 0018-9464
  • Conference paper
    Rakovic SV, Kerrigan EC, Mayne DQ, 2003,

    Reachability computations for constrained discrete-time systems with state- and input-dependent disturbances

    , New York, 42nd IEEE conference on decision and control, Maui, HI, 9 - 12 December 2003, Publisher: IEEE, Pages: 3905-3910
  • Conference paper
    Melovic D, Strbac G, 2003,

    Statistical model for design of distribution network

    , IEEE Power Tech Conference Proceedings, 23 - 26 June 2003, Bologna, Italy, Publisher: IEEE
  • Journal article
    Arutyunov A, Vinter RB, 2003,

    The method of finite approximations in optimal control theory

    , Differential Equations, Vol: 39, Pages: 1443-1451, ISSN: 0012-2661
  • Conference paper
    Sharp R, Evangelou S, Limebeer DJN, Sharp R, Evangelou S, Limebeer DJN, Sharp R, Evangelou S, Limebeer DJNet al., 2003,

    Improved modelling of motorcycle dynamics (Article no.MB2003-029)

    , Lisbon, ECCOMAS Thematic Conference, Multibody Dynamics 2003, 1 - 4 July 2003, Lisbon, Portugal, Publisher: IDMEC, Pages: 1-26
  • Conference paper
    Ortega R, Astolfi A, Hsu L, 2003,

    An immersion and invariance approach to model reference adaptive control

    , 22nd Chinese control conference, 11 - 14 August 2003, Yichang, Hubei, China, Pages: 685-689
  • Conference paper
    Sirisumrannukul S, Strbac G, 2003,

    A tool for trading in power exchanges under the new electricity trading arrangement

    , IEEE Power Tech Conference Proceedings, 23 - 26 June 2003, Bologna, Italy, Publisher: IEEE
  • Conference paper
    Greatbanks JA, Popovic DH, Begovic M, Pregelj A, Green TCet al., 2003,

    On optimization for security and reliability of power systems with distributed generation

    , Bologna, Italy, 2003 IEEE Bologna PowerTech, Bologna, Italy, 23 - 26 June 2003, Publisher: IEEE, Pages: 1-8

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