Model Predictive Control with Fatigue-Damage Minimization through the Dissipativity Property of Hysteresis Operators

In this paper, we propose an approximation method for the well-known fatigue-damage estimation of rainflow counting (RFC) using the dissipativity property of hysteresis operators that can be embedded in model predictive control (MPC) frameworks. Firstly, we revisit results that establish the equivalence between RFC to an energy dissipation property of an infinite-dimensional operator of the Preisach hysteresis model. Subsequently, we approximate the Preisach model using a finite- dimensional differential Duhem hysteresis model and propose an extended MPC scheme that takes into account the dissipated energy of Duhem hysteresis model as a damage proxy in the optimization problem formulation. Lastly, we present an example of control design for damage minimization in the shaft of a wind turbine where we illustrate the proposed strategy

Agent based demand flexibility management for wind power forecasting error mitigation using the SG-BEMS framework

The integration process of renewable energy sources (RES) and distributed energy resources (DER) into the power system, is characterized by concerns that originate from their stochastic and uncontrollable nature. This means that system operators require reliable forecasting tools, in order to ensure efficient and reliable operation. Accordingly, this paper proposes the use of demand flexibility, to counteract the RES forecasting errors. For this purpose, distributed and decentralized intelligence is used, via the SG-BEMS framework, to invoke demand flexibility in a timely and effective fashion, while taking into account the negative effects on the building occupants comfort. Lastly, numerical results from a simulated case of study are presented, which confirm that demand flexibility can be used to mitigate the magnitude of forecast errors

Wind Turbine Control with Active Damage Reduction through Energy Dissipation

In this paper we propose an active damage reduction control strategy for wind turbines based on dissipated energy. To this end we rely on the equivalences relating both damage in the rainflow counting sense and dissipated energy to the variations of Preisach hysteresis operators. Since dissipation theory is well suited for control systems, we adopt the dissipated energy of a Duhem hysteresis model that is described by a differential equation. Accordingly, we incorporate the dissipated energy into the optimal control problem formulation as a proxy to the damage. Lastly, the proposed strategy is evaluated with NREL’s FAST high-fidelity non-linear wind turbine

Towards Ocean Grazer's Modular Power Take-Off System Modeling:A Port-Hamiltonian Approach

This paper presents a modular modeling framework for the Ocean Grazer's Power Take-Off (PTO) system, which operates as an array of point-absorber type devices connected to a hydraulic system. The modeling is based on the port-Hamiltonian (PH) framework that enables energy-based analysis and control of the PTO system. Firstly, a modular model of a point-absorber hydraulic system, which represents the main building block of the PTO, is presented. The model consists of wave-mechanical and hydraulic subsystems that are interconnected with a transformer-type interconnection. Secondly, we show passivity of the point-absorber hydraulic element and the accumulation of potential energy, which is due to the novel pumping mechanism of the point-absorber. Finally, we illustrate these properties through simulation results