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Journal articleBianchini G, Falugi P, Tesi A, et al., 2007,
A convex lower bound for the real l(2) parametric stability margin of linear control systems with restricted complexity controllers
, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 52, Pages: 514-520, ISSN: 0018-9286- Author Web Link
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- Citations: 2
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Journal articlePudjianto D, Ramsay C, Strbac G, 2007,
Virtual power plant and system integration of distributed energy resources
, IET Renewable Power Generation, Vol: 1, Pages: 10-16 -
Journal articlePogaku N, Prodanovic M, Green TC, 2007,
Modeling, analysis and testing of autonomous operation of an inverter-based microgrid
, IEEE Transactions on Power Electronics, Vol: 22, Pages: 613-625, ISSN: 1941-0107The analysis of the small-signal stability of conventionalpower systems is well established, but for inverter basedmicrogrids there is a need to establish how circuit and controlfeatures give rise to particular oscillatory modes and which ofthese have poor damping. This paper develops the modeling andanalysis of autonomous operation of inverter-based microgrids.Each sub-module is modeled in state-space form and all arecombined together on a common reference frame. The modelcaptures the detail of the control loops of the inverter but not theswitching action. Some inverter modes are found at relatively highfrequency and so a full dynamic model of the network (ratherthan an algebraic impedance model) is used. The complete modelis linearized around an operating point and the resulting systemmatrix is used to derive the eigenvalues. The eigenvalues (termed“modes”) indicate the frequency and damping of oscillatorycomponents in the transient response. A sensitivity analysis is alsopresented which helps identifying the origin of each of the modesand identify possible feedback signals for design of controllersto improve the system stability. With experience it is possible tosimplify the model (reduce the order) if particular modes arenot of interest as is the case with synchronous machine models.Experimental results from a microgrid of three 10-kW invertersare used to verify the results obtained from the model.
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Journal articleBlack M, Strbac G, 2007,
Value of bulk energy storage for managing wind power fluctuations
, IEEE TRANSACTIONS ON ENERGY CONVERSION, Vol: 22, Pages: 197-205, ISSN: 0885-8969- Author Web Link
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- Citations: 200
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Journal articleAstolfi A, Karagiannis D, Ortega R, 2007,
Stabilization of uncertain nonlinear systems via Immersion and Invariance
, European Journal of Control, Vol: 13, Pages: 204-220 -
Journal articleJabr R A, Pal B C, 2007,
A Conic Programming Approach for Static Voltage Stability Analysis in Radial Networks
, IET Generation Transmission & Distribution, Pages: 203-208That the problem of computing the capacity limit of a radial distribution system can be formulated as a second-order cone program is shown. The implications of the conic programming formulation are 2-fold. First, the load capability of the radial system can be obtained using existing efficient implementations of polynomial time interior-point algorithms, thus avoiding the need for running a sequence of load flow solutions. Secondly, the conic objective function yields a voltage stability indicator (SI). This indicator quantifies the maximum percentage by which the current load profile can be uniformly increased before voltage collapse occurs. The proposed method is validated by computing the load capability and voltage SIs of 11 different distribution systems. Comparisons are carried out with five previously published voltage SIs
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Journal articleDe Leenheer P, Sontag ED, Angeli D, 2007,
Monotone chemical reaction networks
, Journal of Mathematical Chemistry, Vol: 41, Pages: 295-314 -
Conference paperAstolfi A, Karagiannis D, Ortega R, 2007,
Stabilization of uncertain nonlinear systems via immersion and invariance
, 44th IEEE Conference on Decision Control/European Control Conference, Pages: 204-220This paper presents a method for designing asymptotically stabilising and adaptive control laws for uncertain nonlinear systems. The method relies upon the notions of system immersion and manifold invariance and, in principle, does not require the knowledge of a (control) Lyapunov function. The construction of the stabilising control laws resembles the procedure used in nonlinear regulator theory to derive the (invariant) output-zeroing manifold and its friend, and is well suited,for instance, in situations where we know a stabilising controller of a nominal reduced-order model, which we would like to robustify with respect to higher-order dynamics.In adaptive control problems the method yields stabilising schemes that counter the effect of the uncertain parameters adopting a robustness perspective. This is in contrast with most existing adaptive designs that (relying on certain matching conditions) treat these terms as disturbances to be rejected. The construction does not invoke certainty equivalence, nor requires a linear parameterisation. Furthermore, viewed from a Lyapunov perspective, it provides a procedure to add cross terms between the parameter estimates and the plant states.To illustrate the concepts presented in this paper we introduce several academic and physical examples, including a mechanical system with flexibility modes, an electromechanical system with parasitic actuator dynamics, and an adaptive, nonlinearly parameterised, visual servoing problem.
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Journal articleProdanovic M, De Brabandere K, Van den Keybus J, et al., 2007,
Harmonic and reactive power compensation as ancillary services in inverter-based distributed generation
, IET - Generation, Transmission and Distribution, Vol: 1, Pages: 432-438The introduction of distributed generation, DG, into low-voltage (LV) networks opens up the possibility of supplying ancillary services to aid network management and to maintain powerquality. DG itself can cause voltage magnitude difficulties when injecting real power into networks with high R/X ratios, but control of reactive power injection can help overcome this. Continuous control and support only at the voltage limit conditions (to avoid unnecessary reactive power flows in normal conditions) are explored. Relatively high-impedance LV networks are prone to harmonic distortion from nonlinear loads. A variety of control methods that emphasise either harmonic-line flows or local-voltage distortion are examined, and a compromise method based on resistance emulation is shown to be effective. Experimental results from a single-phase laboratory network and 2 kVA inverter are used to illustrate how these additional control functions can be integrated into the existing control scheme for real-power management. Decomposition of observed voltages and currents into harmonic terms that are phase synchronised to the grid voltage is a challenge in real-time systems. Kalman observers are used to achieve this with an additional advantage of avoiding explicit phase-locking while producing quadrature components useful in instantaneous calculation of reactive power and in providing feed-forward compensation terms.
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Journal articleAstolfi A, 2007,
A remark on an example by Teel-Hespanha with applications to cascaded systems
, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, Vol: 52, Pages: 289-293, ISSN: 0018-9286- Author Web Link
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- Citations: 4
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Journal articleGross R, Heptonstall P, Leach M, et al., 2007,
Renewables and the grid: understanding intermittency
, Proceedings of the Institution of Civil Engineers - Energy, Vol: 160, Pages: 31-41This paper reviews the key issues and findings of the UK Energy Research Centre report on the costs and impacts of intermittent or variable renewable electricity-generating technologies. The relevant principles of managing electricity networks are examined and aspects that change when significant intermittent generation is added are analysed.The impacts and costs of intermittent generators can be quantified only in the context of the characteristics of the system of which they form part. The principal reasons why these impacts differ from one system to another are examined and explained. The evidence for likely impactsand costs in the UK, at intermittent penetration levels up to 20% of total electricity supplied, is analysed. The two main categories of impact are on system balancing and system reliability, and costs are quantified for these factors.Estimates are in the range of an additional £2–3/MWh for system balancing and £3–5/MWh for system reliability.
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Conference paperCasson AJ, Yates DC, Patel S, et al., 2007,
Algorithm for AEEG data selection leading to wireless and long term epilepsy monitoring
, Engineering in Medicine and Biology Society, 2007. EMBS 2007. 29th Annual International Conference of the IEEE, Pages: 2456-2459, ISSN: 1557-170X -
Conference paperCasson AJ, Yates DC, Patel S, et al., 2007,
An analogue bandpass filter realisation of the Continuous Wavelet Transform
, Engineering in Medicine and Biology Society, 2007. EMBS 2007. 29th Annual International Conference of the IEEE, Publisher: IEEE, Pages: 1850-1854, ISSN: 1557-170X -
Journal articleAngeli D, Astolfi A, 2007,
A tight small-gain theorem for not necessarily ISS systems
, SYSTEMS & CONTROL LETTERS, Vol: 56, Pages: 87-91, ISSN: 0167-6911- Author Web Link
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- Citations: 65
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Conference paperAstolfi A, 2007,
A new look at model reduction by moment matching for linear systems
, 46th IEEE Conference on Decision and Control, Publisher: IEEE, Pages: 2208-2213, ISSN: 0743-1546- Author Web Link
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- Citations: 8
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Conference paperLi Z, Zolotas AC, Jaimoukha IM, et al., 2007,
Output selection under control and fault detectability considerations
, 15th Mediterranean Conference on Control and Automation, Publisher: IEEE, Pages: 778-+, ISSN: 2325-369X -
Journal articleChang H, Astolfi A, 2007,
Leading to long-term nonprogressor via gradual reduction of drug dose with immune dynamics strongly dependant on target cells
, 2007 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-16, Pages: 1094-1097, ISSN: 1094-687X- Author Web Link
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- Citations: 1
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Conference paperOrukpe PE, Jaimoukha IM, EI-Zobaidi HMH, 2007,
Model predictive control based on mixed H-2/H-infinity control approach
, 26th American Control Conference, Publisher: IEEE, Pages: 4421-4424, ISSN: 0743-1619- Author Web Link
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- Citations: 23
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Conference paperZolotas AC, Korba P, Chaudhuri B, et al., 2007,
H-2 LMI-based robust control for damping oscillations in power systems
, IEEE International Conference on System of Systems Engineering, Publisher: IEEE, Pages: 545-+ -
Conference paperPudjianto D, Castro M, Djapic P, et al., 2007,
Transmission investment and pricing in systems with significant penetration of wind generation
, IEEE-Power-Engineering-Society General Meeting, Publisher: IEEE, Pages: 4563-+, ISSN: 1932-5517 -
Conference paperMajumder R, Pal BC, Chaudhuri B, et al., 2007,
Design and real time implementation of LMI based robust damping controllers for power systems
, IEEE International Conference on System of Systems Engineering, Publisher: IEEE, Pages: 654-660 -
Conference paperOrukpe PE, Jaimoukha IM, 2007,
A semidefinite relaxation for the quadratic minimax problem with application to H-infinity model predictive control
, 46th IEEE Conference on Decision and Control, Publisher: IEEE, Pages: 1708-1712, ISSN: 0743-1546 -
Conference paperTan CW, Green TC, Hernandez-Aramburo CA, 2007,
A current-mode controlled maximum power point tracking converter for building integrated photovoltaics
, 12th European Conference on Power Electronics and Applications, Publisher: IEEE SERVICE CTR, Pages: 1144-1153- Author Web Link
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- Citations: 1
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Journal articleCobelo I, Shafiu A, Jenkins N, et al., 2007,
State estimation of networks with distributed generation
, EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Vol: 17, Pages: 21-36, ISSN: 1430-144X- Author Web Link
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- Citations: 22
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Conference paperMazars E, Jaimoukha IM, Li Z, et al., 2007,
Fault detection and isolation filter design for systems subject to polytopic uncertainties
, 15th Mediterranean Conference on Control and Automation, Publisher: IEEE, Pages: 1662-+, ISSN: 2325-369X- Author Web Link
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- Citations: 2
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Conference paperChang H, Astolfi A, 2007,
Immune response's enhancement via controlled drug scheduling
, 46th IEEE Conference on Decision and Control, Publisher: IEEE, Pages: 2783-2788, ISSN: 0743-1546 -
Journal articleMayne DQ, 2007,
Personal impressions of the dawn of modern control
, EUROPEAN JOURNAL OF CONTROL, Vol: 13, Pages: 61-70, ISSN: 0947-3580- Author Web Link
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- Citations: 1
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Conference paperTerzija V, Elkalashy NI, Preston G, et al., 2007,
Detection of arcing faults: Modelling, simulation, testing and algorithms aspects
, IEEE Lausanne Powertech, Publisher: IEEE, Pages: 1147-+- Author Web Link
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- Citations: 5
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Conference paperTanelli M, Osorio G, Di Bernardo M, et al., 2007,
Limit cycles analysis in hybrid Anti-lock Braking Systems
, 46th IEEE Conference on Decision and Control, Publisher: IEEE, Pages: 2605-+, ISSN: 0743-1546- Author Web Link
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- Citations: 2
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Conference paperBarnes M, Ventakaramanan G, Kondoh J, et al., 2007,
Real-world Microgrids - An overview
, IEEE International Conference on System of Systems Engineering, Publisher: IEEE, Pages: 37-+- Author Web Link
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- Citations: 151
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