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Abstract-A large class of three-phase electrical power systems possess symmetry conditions that make it possible to describe their behavior using single-input single-output transfer functions with complex coefficients. In such cases, an extended root locus method can be used to design control laws, even though the actual systems are multi-input multi-output. In this paper, the symmetric conditions for a large class of power systems are analyzed. Then, the root locus method is revisited for systems with complex coeffcients and used for the analysis and control design of power systems. To demonstrate the benefits of the approach, the paper includes two examples: a doubly-fed induction machine and a three-phase LCL inverter.

Abstract:A family of passivity-based controllers for dynamic positioning of ships is presented. The authors exploit the idea of shaping the energy function of the closed-loop system to obtain different formulations of the passivity-based control law using the interconnection and damping assignment-passivity-based control (IDA-PBC) methodology. A salient feature of this study is that the proposed control laws are output feedback controllers and the relative velocity measurement is not required. First, we design and analyse two static controllers which can be seen as a non-linear version of the conventional proportional-derivative (PD) controllers. In presence of unknown disturbances, these controllers do not provide the desired regulation properties. To remove this discrepancy we propose, also in the context of the IDA-PBC technique, a dynamic extension of the system and obtain two new controllers that have the desired regulation properties. These new control laws can be seen as a non-linear version of the conventional proportional-integral-derivative (PID) controllers. Simulations are included to validate the theoretical results.

We consider a doubly-fed induction machine-controlled through the rotor voltage and connected to a variable local load-that acts as an energy-switching device between a local prime mover (a flywheel) and the electrical power network. The control objective is to optimally regulate the power flow which is achieved commuting between two different steady-state regimes. We first show that the zero dynamics of the system is only marginally stable complicating its control via feedback linearization. Instead, we apply the energy-based Interconnection and Damping Assignment Passivity-Based Control technique that does not require stable invertibility. It is shown that the partial differential equation that appears in this method can be obviated fixing the desired closed-loop total energy and adding new terms to the interconnection structure. Furthermore, to obtain a globally defined control law we introduce a state-dependent damping term that has the nice interpretation of effectively decoupling the electrical and mechanical parts of the system. This results in a globally asymptotically stabilizing controller parameterized by two degrees of freedom, which can be used to implement the power management policy. An indirect adaptive scheme for the rotor and stator resistances is also introduced. The controller is simulated and shown to work satisfactorily for various realistic load changes. * This work has been done in the context of the European sponsored project Geoplex with reference code IST-2001-34166. Further information is available at http://www.geoplex.cc † The work of Carles Batlle has been partially done with the support of the spanish project Mocoshev, DPI2002-03279.‡ The work of Arnau Dòria-Cerezo was (partially) supported through a European Community Marie Curie Fellowship in the framework of the European Control Training Site.

ADVERTIMENT. La consulta d'aquesta tesi queda condicionada a l'acceptació de les següents condicions d'ús: La difusió d'aquesta tesi per mitjà del servei TDX (www.tesisenxarxa.net) ha estat autoritzada pels titulars dels drets de propietat intel·lectual únicament per a usos privats emmarcats en activitats d'investigació i docència. No s'autoritza la seva reproducció amb finalitats de lucre ni la seva difusió i posada a disposició des d'un lloc aliè al servei TDX. No s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant al resum de presentació de la tesi com als seus continguts. En la utilització o cita de parts de la tesi és obligat indicar el nom de la persona autora.ADVERTENCIA. La consulta de esta tesis queda condicionada a la aceptación de las siguientes condiciones de uso: La difusión de esta tesis por medio del servicio TDR (www.tesisenred.net) ha sido autorizada por los titulares de los derechos de propiedad intelectual únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con finalidades de lucro ni su difusión y puesta a disposición desde un sitio ajeno al servicio TDR. No se autoriza la presentación de su contenido en una ventana o marco ajeno a TDR (framing). Esta reserva de derechos afecta tanto al resumen de presentación de la tesis como a sus contenidos. En la utilización o cita de partes de la tesis es obligado indicar el nombre de la persona autora. WARNING.On having consulted this thesis you're accepting the following use conditions: Spreading this thesis by the TDX (www.tesisenxarxa.net) service has been authorized by the titular of the intellectual property rights only for private uses placed in investigation and teaching activities. Reproduction with lucrative aims is not authorized neither its spreading and availability from a site foreign to the TDX service. Introducing its content in a window or frame foreign to the TDX service is not authorized (framing). This rights affect to the presentation summary of the thesis as well as to its contents. In the using or citation of parts of the thesis it's obliged to indicate the name of the author AcknowledgmentsUnas cuantas líneas es poco para agradecer la compañía, apoyo, formación y guía de tantas personas que me han ayudado a alcanzar esta meta.Primero quiero dar gracias a Dios, Señor y dador de vida por todos los regalos y bendiciones recibidas. A mi familia por su formación, apoyo y preocupación en cada momento. A mi esposa por estar siempre a mi lado y soportar todas las restricciones que imponen la dedicación a una tesis; por la compañía y el apoyo en todo sentido.Pasando al ámbito profesional, diversas personas han marcado mi vida y me han hecho enamorar de la ciencia. Inicialmente, en la Universidad Nacional de Colombia varios profesores me han mostrado la belleza de las máquinas eléctricas (Jorge Fernando Gutiérrez), la electrónica de potencia (Eduardo Antonio Cano) y el Control (Fabiola Angulo), gracias ...

SUMMARYA controller able to achieve bidirectional power flow for a boost-like full-bridge rectifier is presented. It is shown that no single output yields a stable zero dynamics for power flowing both ways. The controller is computed using port Hamiltonian passivity techniques for a suitable generalized state space averaging truncation of the system, which transforms the control objectives, namely specified output mean value of the voltage dc-bus and unity input power factor in the ac side, into a regulation problem. Simulation and experimental results for the full system confirm the correctness of the simplifications introduced to obtain the controller.

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International audienceIn this brief, a new control scheme is presented for the doubly fed induction machine (DFIM). The proposed control algorithm offers the advantages of proven stability and remarkable simplicity. In contrast to the classical vector control method, where the DFIM is represented in a stator-flux-oriented frame, a model with orientation of the stator voltage is adopted. This approach allows the decomposition of the active and reactive powers on the stator side and their regulation on the rotor side. A main contribution of this brief is the use of the Hurwitz test for polynomials with complex coefficients that has had little prior application in control theory. This results in a proof that a proportional-integral (PI) control regulating the stator currents ensures global stability for a feedback-linearized DFIM. The specific condition that the PI gains must satisfy is derived as a simple inequality. The PI controller has a particular structure that directly relates the d-component of the rotor voltages to the q-component of the stator currents and vice versa. The feedback linearization stage only uses the direct measurement of the rotor and stator currents and is thus easily implementable. Furthermore, it is also shown that the PI controller (without the feedback linearization terms) is also stable for a large range of control gains and does not require the knowledge of the machine parameters. Finally, the control system is validated in simulations and in experiments