Author Contributions
Conceptualization, M.-H.C.; methodology, M.-H.C.; software, C.-J.C., C.-H.C., C.L., T.-Y.L. and M.-H.C.; validation, C.-J.C., C.-H.C., C.L. and T.-Y.L.; formal analysis, C.-J.C., C.-H.C., C.L. and T.-Y.L.; writing—original draft preparation, C.-J.C. and M.-H.C.; writing—review and editing, M.-H.C.; supervision, M.-H.C.; project administration, M.-H.C.; funding acquisition, M.-H.C. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Wind-turbine foundation-types in different water depths.
Figure 1.
Wind-turbine foundation-types in different water depths.
Figure 2.
Dynamic co-simulation framework.
Figure 2.
Dynamic co-simulation framework.
Figure 3.
Simulation model of 15 MW floating wind turbine with UMaine VolturnUS-S semi-submersible floating platform and mooring system for water depth of 70 m.
Figure 3.
Simulation model of 15 MW floating wind turbine with UMaine VolturnUS-S semi-submersible floating platform and mooring system for water depth of 70 m.
Figure 4.
UMaine VolturnUS-S Semi-submersible platform modeling in SIMPACK.
Figure 4.
UMaine VolturnUS-S Semi-submersible platform modeling in SIMPACK.
Figure 5.
Mooring-System Configuration.
Figure 5.
Mooring-System Configuration.
Figure 6.
Power-generation process.
Figure 6.
Power-generation process.
Figure 7.
DFIG Grid-Connected System.
Figure 7.
DFIG Grid-Connected System.
Figure 8.
Layout of Hydraulic Pitch-Control System.
Figure 8.
Layout of Hydraulic Pitch-Control System.
Figure 9.
15 MW Wind-Turbine Power Curve.
Figure 9.
15 MW Wind-Turbine Power Curve.
Figure 10.
Relationship between Rotor Speed and Wind Speed.
Figure 10.
Relationship between Rotor Speed and Wind Speed.
Figure 11.
Fuzzy Sliding-Mode Controller.
Figure 11.
Fuzzy Sliding-Mode Controller.
Figure 12.
Wind Turbine Overall-Control-System Block Diagram.
Figure 12.
Wind Turbine Overall-Control-System Block Diagram.
Figure 13.
Simulation results of floating wind turbine with wind speed from 0 to 25 m/s and no wave by FSMC: (a) wind speed, (b) wave height, (c) rotor speed, (d) rotor-speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Figure 13.
Simulation results of floating wind turbine with wind speed from 0 to 25 m/s and no wave by FSMC: (a) wind speed, (b) wave height, (c) rotor speed, (d) rotor-speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Figure 14.
Simulation results of floating wind turbine by FSMC, with pitch-rate feedback in normal conditions; wind speed from 3 m/s to 16 m/s with 3% turbulence intensity, wave height of 1.4 m, and wave period of 7.8 s: (a) wind speed, (b) wave height, (c) rotor speed, (d) rotor-speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Figure 14.
Simulation results of floating wind turbine by FSMC, with pitch-rate feedback in normal conditions; wind speed from 3 m/s to 16 m/s with 3% turbulence intensity, wave height of 1.4 m, and wave period of 7.8 s: (a) wind speed, (b) wave height, (c) rotor speed, (d) rotor-speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Figure 15.
Simulation results under 50-year return-period extreme conditions, with wind speed 57 m/s and 3% turbulence: (a) wind speed, (b) wave height, (c) rotor speed, (d) roto- speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Figure 15.
Simulation results under 50-year return-period extreme conditions, with wind speed 57 m/s and 3% turbulence: (a) wind speed, (b) wave height, (c) rotor speed, (d) roto- speed error, (e) output power, (f) generator torque, (g) blade-pitch, (h) tip-speed ratio, (i) floater surge, (j) floater sway, (k) floater heave, (l) floater roll, (m) floater pitch, (n) floater yaw, (o) mooring-line x-direction tension, (p) mooring-line y-direction tension, (q) mooring-line z-direction tension, (r) mooring-line tension.
Table 1.
Beaufort Scale.
Beaufort Number | Wind Speed (m/s) | Wave Height (m) |
---|
0 | 0–0.2 | 0–0.1 |
1 | 0.3–1.5 | 0.1–0.3 |
2 | 1.6–3.3 | 0.3–0.5 |
3 | 3.4–5.4 | 0.5–0.9 |
4 | 5.5–7.9 | 0.9–1.25 |
5 | 8–10.7 | 1.25–2.5 |
6 | 10.8–13.8 | 2.5–3 |
7 | 13.9–17.1 | 3–4 |
8 | 17.2–20.7 | 4–6 |
9 | 20.8–24.4 | 6–9 |
10 | 24.5–28.4 | 9–11 |
Table 2.
IEA 15 MW Wind-Turbine Specifications.
Table 2.
IEA 15 MW Wind-Turbine Specifications.
Parameter | Value | Unit |
---|
Rotor orientation | Upwind | - |
Control | Variable speed | - |
| collective pitch | - |
Cut-in wind speed | 3 | m/s |
Cut-out wind speed | 25 | m/s |
Rated wind speed | 10.59 | m/s |
Rated electrical power | 15 | MW |
Number of blades | 3 | |
Rotor diameter | 240 | m |
Table 3.
Floating-Tower Geometric Properties.
Table 3.
Floating-Tower Geometric Properties.
Parameter | Value | Unit |
---|
Mass | 1263 | ton |
Length | 129.582 | m |
Young’s Modulus | 2.00 1011 | Pa |
Shear Modulus | 7.93 1010 | Pa |
Density | 7850 | kg/m3 |
Table 4.
Blade Key Parameters.
Table 4.
Blade Key Parameters.
Parameter | Value | Unit |
---|
Blade Mass | 65.228 | ton |
Blade length | 117 | m |
Tip Prebend | 4.00 | m |
Max Chord | 5.77 | m |
Blade Ixx | 4.63 × 107 | kg m2 |
Blade Iyy | 4.63 × 107 | kg m2 |
Blade Izz | × 104 | kg m2 |
Table 5.
Floating-platform properties.
Table 5.
Floating-platform properties.
Parameter | Value | Unit |
---|
Hull Displacement | 20,206 | m3 |
Hull Steel Mass | 3914 | ton |
Tower Interface Mass | 100 | ton |
Ballast Mass (Fixed/Fluid) | 2540/11,300 | ton |
Draft | 20 | m |
Freeboard | 15 | m |
Table 6.
Mooring-System Properties.
Table 6.
Mooring-System Properties.
Parameter | Value | Unit |
---|
Number of Lines | 3 | - |
Anchor Depth | 70 | m |
Fairlead Depth | 14 | m |
Anchor Radial Spacing | 779.6 | m |
Fairlead Radial Spacing | 58.00 | m |
Line Unstretched Length | 789.64 | m |
Nominal Chain Diameter | 0.185 | m |
Dry-Line Linear Density | 685 | kg/m |
Extensional Stiffness | 3.27 9 | N |