Prediction-Based Super Twisting Sliding Mode Load Frequency Control for Multi Area Interconnected Power Systems with State and Input Time Delays using Disturbance Observer

International audienceA shift in paradigm from dedicated to open communication channels in power systems have made them prone to constant and time varying delays. This paper tackles a novel load frequency control (LFC) problem in the presence of constant and time varying delays in state and control input under load disturbances. The presence of time delays can deteriorate the performance of the controller or even destabilize the system. The above problem is addressed through a prediction-based super twisting sliding mode control (ST-SMC) using a state and disturbance observer. The proposed design achieves finite time convergence of frequency and tie line power deviation. The said design is validated under ramp and random step disturbance, with nonlinearities like generation rate constraints and governor deadband, with an integration of renewable energy and also with IEEE 39 bus power system. The closed loop stability is proven thanks to candidate Lyapunov function and verified by simulations

Predictive scheme for observer-based control of LTI systems with unknown disturbances

International audienceIn this work, it is shown that the results introduced in [1], that hold for full state measurement, can be extended to partial state measurement. In particular, it is proven that the combination of an observer with the new predictive scheme of [1] leads to a better disturbance attenuation than using the same observer with the standard predictive scheme. Finally, some simulations illustrate the results for constant and time-varying disturbances

New predictive scheme for the control of LTI systems with input delay and unknown disturbances

International audienceA new predictive scheme is proposed for the control of Linear Time Invariant (LTI) systems with a constant and known delay in the input and unknown disturbances. It has been achieved to include disturbances effect in the prediction even though there are completely unknown. The Artstein reduction is thenrevisited thanks to the computation of this new prediction. An extensive comparison with the standard scheme is presented throughout the article. It is proved that the new scheme leads to feedback controllers that are able to reject perfectly constant disturbances. For time-varying ones, a better attenuation is achieved for a wide range of perturbations and for both linear and nonlinear controllers. A criterion is given to characterize this class of perturbations. Finally, some simulations illustrate the results

Delay and state observer for SISO LTI systems

International audienceThis paper deals with the problem of state and delay estimation for SISO LTI systems, with unknown time-varying delay in the input. Thanks to an adequate approximation of the delayed input by the Taylor’s theorem, an original approach based on observer design is proposed in order to estimate both state and delay. This new technique allows the estimation of time-varying delay. The convergence of the observer is formally proved. The efficiency of the method is widely illustrated by simulations

Predictive control of disturbed systems with input delay: experimental validation on a DC motor

International audienceThis paper deals with the speed control of a DC motor with known input delay and unknown disturbances. A recent predictive technique is used in order to design two controllers that will be able to satisfactorily reject disturbances in spite of the time delay. A comparison between the Artstein reduction method and this new one is performed throughout the article. The control laws are validated first by simulation and then by a practical implementation. The paper presents the very first application of this new predictive method

Delay Estimation and Predictive Control of Uncertain Systems With Input Delay: Application to a DC Motor

International audienceIt is well-known that standard predictive techniques are not very robust to parameter uncertainties and to external disturbances. Furthermore, they require the exact knowledge of the delay. In practice, these constraints are rarely satisfied. In this paper, solutions are presented to allow the use of predictive control in presence of external disturbances, parameter uncertainties and an unknown input delay. First, a recent predictive control method developed to attenuate the effect of external disturbances is shown to be also robust to parameter uncertainties. In addition, a delay estimator is presented to estimate unknown time-varying delays. Theoretical results are widely illustrated through experimental tests on a DC motor

Interconnected delay and state observer for nonlinear systems with time-varying input delay

International audienceThis work presents a general framework to estimate both state and delay thanks to two interconnected observers. This scheme can be applied to a large class of nonlinear systems with time-varying input delay. In order to illustrate this approach, a new delay observer based on an optimization technique is proposed. Theoretical results are illustrated and compared with existing works in simulation

Study of Distributed Beamforming for Wireless Power Transfer in Presence of RF Impairments

International audienceFor an equivalent performance (sensitivity, communication range, computational capability, etc.), the energy efficiency of connected devices is continuously increasing. Providing the energy for such objects by the means of electromagnetic waves (wireless power transfer) becomes a feasible option in various scenarios, especially those in which the use of conventional energy resources (e.g. batteries) is unfeasible.This paper tackles a particular method of wireless power transfer, which is the distributed beamforming, i. e. the use of several sources, spatially distributed and which are coordinating together in order to maximize the power of the electromagnetic field in a particular location. Through simulation results, this paper highlights the robustness of this approach to different nonidealities, i.e. frequency and phase synthesis, phase noise and channel characteristics. A first experimental setup is also presented