Bounded Control of a General Extended Chained Form Systems

International audienceIn this paper, a state feedback control is proposed for the control of second-order chained form system with bounded inputs. The feedback law is based on a receding horizon strategy that provides convergence of the system to any desired final state. Numerical simulations are given to show the effectiveness of the proposed control strategy

Voltage support by optimal integration of Plug-in Hybrid Electric Vehicles to a Residential Grid

International audienceThis paper provides a linear approach to compute the voltages at any node on a residential grid based on the house instantaneous load and the presence of charging Plug- In Hybrid Electric Vehicles (PHEV) on the grid (and the corresponding instantaneous consumption or injection). Based on this linear operation, the paper provides a detailed linear programming formulation of the problem of charging the PHEVs while providing a voltage support service to the grid. Multiple evaluation cases are included in order to test the ability of the approach to maintain voltages within safety limits and provide optimal consumption/injection policies. An additional case is included to prove the potential of the PHEVs to solve existing voltage technical issues on a residential grid

Control of an airborne wind energy system with a Magnus effect

International audienceThe control of an airborne wind energy system with a Magnus effect device has been studied. The proposed strategy aims to control the amount of the output energy produced for a given cycle. The control scheme has been applied numerically and experimentally on a small scale indoor setup of Gipsa-lab, and validated numerically for Omnidea's experimental platform. Results have shown the good performance of the proposed control strategy

Kite Generator System Periodic Motion Planning Via Virtual Constraints

International audienceThis paper presents a new control strategy for Kite Generator System (KGS). The proposed feedback strategy is based on motion planning using the virtual constraint approach and ensures exponential orbital stability of the desired trajectory. The strategy is detailed, applied and tested via numerical simulations and showed good convergence to a desired periodic motion

A distributed cooperative control scheme with optimal priority assignment and stability assessment

International audienceIn this paper, a distributed partially cooperative control framework is proposed for a network of linear interconnected subsystems. It is assumed that each subsystem in the network possesses its own objective and a corresponding nominal interaction-free state feedback law. The proposed framework enables each subsystem to compute an additional control term in order to help maintaining the integrity of the overall network. As this cooperation-like behavior involves relative priority assignment, a communication aware heuristic is proposed with an associated stability assessment that is based on the closed-loop network matrix's spectrum monitoring. Illustrative examples are used to assess the effectiveness of the proposed scheme including a distributed load frequency problem

Kite Generator System Modeling and Grid Integration

International audienceThis paper deals principally with the grid connection problem of a kite-based system, named the "Kite Generator System (KGS)." It presents a control scheme of a closed-orbit KGS, which is a wind power system with a relaxation cycle. Such a system consists of a kite with its orientation mechanism and a power transformation system that connects the previous part to the electric grid. Starting from a given closed orbit, the optimal tether's length rate variation (the kite's tether radial velocity) and the optimal orbit's period are found. The trajectory-tracking problem is not considered in this paper; only the kite's tether radial velocity is controlled via the electric machine rotation velocity. The power transformation system transforms the mechanical energy generated by the kite into electrical energy that can be transferred to the grid. A Matlab/simulink model of the KGS is employed to observe its behavior, and to insure the control of its mechanical and electrical variables. In order to improve the KGS's efficiency in case of slow changes of wind speed, a maximum power point tracking (MPPT) algorithm is proposed

Optimization of a microgrid with renewable energy and distributed generation: A case study

International audienceIn this paper an optimization algorithm is applied on a microgrid with renewable energy and distributed generation. The intermittent electricity in Lebanon leads to widely use diesel generator groups and to install renewable energy in private places in order to cover the consumption during the power cut. The proposed case study consists of three energy hubs integrating renewable energy, diesel engines, and batteries. These three energy hubs cooperate and exchange extra power if needed by applying the proposed algorithm while minimizing the use of diesel engine groups

Extremum seeking control techniques applied to photovoltaic systems with multimodal power curves

International audienceThis paper proposes a modified Perturb and Observe (P&O) Extremum Seeking Control (ESC) technique in presence of multiple maxima. ESC is applied to single-phased grid-connected photovoltaic (PV) arrays which have to provide maximum power irrespective of solar irradiance conditions. In particular, partially shadow conditions may lead to steady-state power curves exhibiting multiple maxima. The power harvested from the PV generator is injected in the single-phased power grid by using two power converter stages: step-up DC-DC converter and DC-AC inverter. When multiple power maxima exist, the amplitude of the perturbation signal plays an important role in successfully tracking the global maximum. Two amplitude modulation strategies are analyzed for the same case study: amplitude modulation by using a first-order-system-response signal and amplitude modulation by using small duty ratio square-wave signal, respectively. MATLAB®/Simulink® numerical simulations are presented in order to assess the two approaches comparatively

Reverse pumping: theory and experimental validation on a multi-kites system

International audienceMost kite wind power systems have a great drawback that wind turbines do not have: they cannot stay in the air if the wind is not strong enough, [7-16]. As a consequence, most of the kite systems need to land when there is no wind, and to take-off once the wind is strong enough. These maneuvers are quite risky because generally the wind gets weak and turbulent close to the ground's surface. Moreover, as the wind can be strong enough at high altitude and weak close to the ground, it might lead to losses in energy production. From a material point of view, "classic" landings and takeoffs need a landing zone, ground handling or infrastructure (such as pylons) that reduces the advantages of kite systems. Some ideas, such as embedded motors or helium balloons, might solve this problem, but they have their own drawbacks such as the weight of the motor and its battery, the necessity of a conductive cable or the need to refill the balloons. The following paper studies a solution called "reverse pumping". It basically consists of providing kinetic energy to the kite by pulling the kite with a rope. This kinetic energy is then transformed into potential energy by gaining altitude. This technique allows to keep the kite airborne in total absence of wind. This paper will study the reverse pumping principle, the constrains on the aerodynamical model, flight simulations and will present the experimental setup used to validate the theoretical study

An application of a centralized model predictive control on microgrids

International audienceIn this paper, a centralized model predictive control (MPC) is applied on a group of interconnected microgrids (MGs) with the main grid. The objective is to maximize the benefits for all the elements constituting the MGs in addition to the benefits of the main grid. The application of MPC in our study needs a forecasting information about energy prices, production power, and loads. The algorithm is tested on five interconnected MGs connected to the main grid. Results have shown the performance of the proposed algorithm, especially for the benefits of MG owners, the coordination between MGs while respecting of the constraints related to each one of them