Paul Maya-Ortiz

Passivity-based control of switched reluctance motors with nonlinear magnetic circuits

In this paper, the torque/speed/position tracking control problem of switched reluctance motors is approached from a passivity-based control perspective. The main characteristics of the presented result are: it belongs to the class of control schemes that take into account the saturation effects present in stator windings and, regarding torque generation, it considers the use of sharing functions. The contribution of the paper is threefold: The controller design is developed using energy-dissipation ideas, the mathematical formalization of the current engineering practice of controlling this kind of machines with a cascade approach, and an extension to previously reported passivity-based controllers for electric machines in the sense that Blondel-Park transformability properties are not required.

Output-feedback IDA stabilisation of an SMIB system using a TCSC

Interconnection and damping assignment (IDA) passivity-based control (PBC) is currently a well-known viable alternative for solving regulation control problems of a wide class of nonlinear systems. However, a distinctive feature that, in spite of its appearance under several applications, has not been exhaustively exploited, is the flexibility that this technique exhibits for designing output-feedback controllers (OFCs). The purpose of this article is to illustrate this attractive characteristic by approaching the (practically important) case study given by the improvement of the transient stability properties of power systems. The particular system composed by a synchronous generator connected to an infinite bus via a thyristor controlled series capacitor is considered. Two OFCs are presented, one that does not involve the unmeasurable state and another that, although including this state, presents some input-to-state stability properties that allow for establishing a sort of separation principle concerning an observer-based structure for the closed-loop system. The advantages of both controllers are illustrated by numerical simulations when a three-phase short circuit at the generator bus is induced.

Comparison between WLS and Kalman Filter method for power system static state estimation

Traditional state estimators, which are based on steady state system model, cannot capture the time-history data. The problem of state estimation combined with multiple sets of measurements is posed in a Kalman Filtering scheme, using a discrete-time model. In this paper, the power system state estimation process, based on Kalman Filtering techniques is discussed; an IEEE 6-bus test system is used to compare the performance with the Weighted Least Square (WLS) method.

Output-feedback IDA control design via structural properties: Application to Thyristor Controlled Series Capacitors

In this paper the properties exhibited by the IDA Passivity-based Controller (PBC) design methodology for developing Output-Feedback Controllers (OFC) are illustrated by means of the particular system composed by a synchronous generator connected to an infinite bus via a Thyristor Controlled Series Capacitors (TCSC). Two OFC are presented, one that does not involve the unmeasurable state and other that, although including this state, present some Input-to-State Stability (ISS) properties that allow for establishing a sort of separation principle concerning an observer-based structure for the closed-loop system.

Global observability analysis of the SR Motor under sensorless operation

This paper presents a global observability analysis of the Switched Reluctance Motor under sensorless operation i.e., only the stator current and voltages are measured. The main contribution of this work is the formal statement of the indistinguishable dynamics of this machine, which describe for the first time, the initial conditions and inputs that cause the loss of observability in this operation condition. The analysis presented concludes that it is impossible to design an observer for every trajectory of the motor. Additionally, there exist singular inputs i.e., inputs that does not distinguish between two initial conditions from the measurements. To illustrate the loss of observability of the Switched Reluctance Motor, some examples are presented.

On the control of switched reluctance motors

In this paper, the control of switched reluctance motors is approached from a passivity-based control perspective. The proposed controller solves the torque/speed/position tracking problem by exploiting the passivity properties of the machine. The methodology design considers the feedback decomposition of the motor model into one electrical and one mechanical passive systems and is divided into the following three steps: control of the electrical sub-system to achieve current tracking, definition of the desired current behaviour to assure torque tracking and design of a speed/position control loop. The contribution of the paper is threefold: the controller design is developed using energy-dissipation ideas; the mathematical formalization of the current engineering practice of controlling this kind of machines with a cascade approach; and the establishment of an extension to previously reported passivity-based controllers for electric machines in the sense that in this case Blondel-Park transformability properties are not required.

Control de Robots Cooperativos con Diseño de un Observador

Uno de los principales problemas en la implementacion de controladores para que un robot realice labores de destreza, es la complejidad de integrar una gran cantidad de sensores cuando se tienen arquitecturas pequenas. Ademas, el costo de operacion se ve incrementado. En este articulo se considera el control de robots cooperativos sin mediciones de velocidad, con el fin de manipular un objeto firmemente. La teoria desarrollada se avala con resultados experimentales