Model and Simulation of a Floating Hybrid Wind and Current Turbines Integrated Generator System, Part II: Hydrodynamics and Acting Forces

Abstract

This work is part of a series of publications that propose a floating hybrid system for which a simulation tool has been developed, called FHYGSYS (Floating Hybrid Generator Systems Simulator). The objective of this series of publications is to analyze the behavior and to evaluate different control strategies of the floating hybrid system. This system consists of an “OC3-Hywind” wind turbine and two marine current turbines presented by the authors in previous publications. This work completes the exposition of the mathematical model of the floating hybrid system started in a previous publication (Part I), in which the inertial, kinematic, and dynamic parts of the model were described. In this second part, the forces acting on the floating system are extensively described, and the turbines are modeled using the so-called One-Dimensional theory (or also known as Simple theory). The results obtained with the FHYGSYS simulation tool have been validated—through a code-to-code comparison—with FASTv8, both in the first part and in this second part of this work.

BEM Turbine Model and PID Control System of a Floating Hybrid Wind and Current Turbines Integrated Generator System

“…Both the wind turbine and the two MCTs are part of the floating hybrid system, so in order to obtain results for their study and validation, it is necessary to have an adequate mathematical model of the system as a whole and of the environment-seawater-in which it is found. A complete mathematical model of the floating hybrid system shown in Figure 1-consisting of a floating OC3-Hywind-type wind turbine [14,20] to which two MCTs have been coupled such as those described in [34,35]-was presented in [36,37], but without using the BEM theory for the modeling of the turbines. The complete mathematical model was implemented in [36,37] using MATLAB ® , and they called the resulting code FHYGSYS.…”

“…A complete mathematical model of the floating hybrid system shown in Figure 1-consisting of a floating OC3-Hywind-type wind turbine [14,20] to which two MCTs have been coupled such as those described in [34,35]-was presented in [36,37], but without using the BEM theory for the modeling of the turbines. The complete mathematical model was implemented in [36,37] using MATLAB ® , and they called the resulting code FHYGSYS. In [36], the kinematic, dynamic, and inertial models were presented and the way in which the added mass of the floating system was computed.…”

“…In [36], the kinematic, dynamic, and inertial models were presented and the way in which the added mass of the floating system was computed. On the other hand, in [37], the method to calculate the hydrodynamics and the rest of the forces acting on the floating hybrid system was described in detail including the modeling of the turbines using One-Dimensional theory.…”

“…In this third installment, the mathematical modeling presented in [36,37] is extended, offering the possibility to choose between the One-Dimensional theory or the BEM theory for turbine modeling in FHYGSYS. In this case, the programming environment used was also MATLAB ® .…”

“…The application of BEM theory in FHYGSYS is illustrated in Figure 2. It sho the modeling of turbine aerodynamics, or hydrodynamics in the case of MCTs, us theory is related to the rest of the mathematical model of the floating hybrid syst The first step for the application of this method in FHYGSYS is the calculati effective fluid velocity vector in each blade element (see Figure 2) by applying t odology described in Section 2.3 in [37]. In this way, a different fluid velocity is for each blade element, which offers an adequate approximation to the real behav the differences in height or depth can be considerable in the turbine blades.…”