f PMSG Z Grid Filter Generator Control System...Generator-side DC-link PMSG Gearbox Generator...
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Chalmers University of Technology Novel Electric Drive Solution for Tidal Power Generation using 5-level NPC converters Department of Energy and Environment Georgios Mademlis [email protected] Tidal energy offers many advantages compared to other renewable energy sources, such as having predictable and reliable power generation and robust nature against climatic changes, since it is not dependent on the wind volatility, rain, snow, clouds and fog. However, the problem of transferring the generated power to the shore in an efficient way is an important issue that needs to be addressed. The increase of the operating voltage of the power generation system using multilevel power converters is an effective way of solving this problem. The aim of this work is to present an optimized drive system using 5-level neutral-point-clamped (NPC) converters that can be used in a tidal power generation system. Fig. 1 Structure of the proposed tidal generation system with two NPC converters Background and Aim Modeling of the Power Generation System Simulation results Conclusions • NPC converters can increase the power density of the electric drive that controls the generator by increasing the operating voltage. As a result, the weight and volume of the underwater cables connecting the PTO with the shore can be decreased. • The multilevel converter topology increases the power quality of the voltage at the point of common coupling with the grid. Therefore, the smaller and more compact passive filters can be used for bringing the THD at acceptable levels. • The feasibility of the proposed power generation system for offshore tidal power plants using 5-level NPC converters has been evaluated through simulation results. • The developed control system of the NPC converters attains stable performance of the whole tidal power system. Fig. 2 Overview of the tidal power-take-off (PTO) system. Financed by European Union’s Horizon 2020 research and innovation program. Fig. 3 Circuit diagram of a 3-phase 5-level NPC converter Fig. 4 Simulation results of the produced generator power and the NPC converter system at the connection to the grid Three-phase 5L NPC Grid-side Ref. cal. Current control Grid synch. (PLL) PCC Filter ω , ρ v S i i Z S Grid i dref Control System abc dq DC link control V DC P ref v q,d i q,d SVM m abc i i v S v q i qref L 2 L 1 C f Q ref Three-phase 5L NPC Generator-side DC-link PMSG Gearbox Generator Current control SVM m abc abc dq Speed control i qref i gen θ gen ω gen v gen V dc V dc v q,d i q,d MPPT ω gen ω ref P ref V DC 1÷4 Nima Saadat [email protected] Division of Electric Power Engineering • The output line-to-line voltage at the point of common coupling with the grid consists of five levels. Therefore, a smaller passive filter can be designed at the output of the topology compared to the 2-level converter topologies. • The rms value of the line-to-line voltage V LL at the connection to the grid is 3.3 kV. • The power produced by the tidal generator is not constant, but changes periodically over time. • The developed control system of the electric drive adjusts to the variating power and remains stable during the whole operation. Yujing Liu [email protected]
Transcript of f PMSG Z Grid Filter Generator Control System...Generator-side DC-link PMSG Gearbox Generator...
Chalmers University of Technology
Novel Electric Drive Solution for Tidal Power
Generation using 5-level NPC converters
Department of Energy and Environment
Georgios [email protected]
Tidal energy offers many advantages compared to other renewable energy sources, such as having predictable and reliable power
generation and robust nature against climatic changes, since it is not dependent on the wind volatility, rain, snow, clouds and fog.
However, the problem of transferring the generated power to the shore in an efficient way is an important issue that needs to be
addressed. The increase of the operating voltage of the power generation system using multilevel power converters is an effective
way of solving this problem. The aim of this work is to present an optimized drive system using 5-level neutral-point-clamped
(NPC) converters that can be used in a tidal power generation system.
Fig. 1 Structure of the proposed tidal generation system with two NPC converters
Background and Aim
Modeling of the Power Generation System
Simulation results
Conclusions
• NPC converters can increase the power density of the electric drive that controls the generator by increasing the operating
voltage. As a result, the weight and volume of the underwater cables connecting the PTO with the shore can be decreased.
• The multilevel converter topology increases the power quality of the voltage at the point of common coupling with the grid.
Therefore, the smaller and more compact passive filters can be used for bringing the THD at acceptable levels.
• The feasibility of the proposed power generation system for offshore tidal power plants using 5-level NPC converters has been
evaluated through simulation results.
• The developed control system of the NPC converters attains stable performance of the whole tidal power system.
Fig. 2 Overview of the tidal power-take-off (PTO) system.
Financed by European Union’s Horizon 2020 research and innovation program.
Fig. 3 Circuit diagram of a 3-phase 5-level
NPC converter
Fig. 4 Simulation results of the produced generator power
and the NPC converter system at the connection to the grid
Three-phase 5L NPCGrid-side
Ref. cal.
Current
control
Grid synch.
(PLL)
PCCFilter
ω , ρ
vS
ii
ZS
Grid
idref
Control System
abc dq
DC link
control
VDC
Pref
vq,d
iq,d
SVM
mabciivS
vqiqref
L2L1
Cf
Qref
Three-phase 5L NPCGenerator-side
DC-link
PMSG
GearboxGenerator
Current
control
SVM
mabc
abc dq
Speed
control
iqref
igen
θgenωgen
vgen
VdcVdc
vq,d
iq,d
MPPT
ωgen
ωrefPref
VDC 1÷4
Nima [email protected]
Division of Electric Power Engineering
• The output line-to-line voltage at the
point of common coupling with the
grid consists of five levels. Therefore,
a smaller passive filter can be
designed at the output of the
topology compared to the 2-level
converter topologies.
• The rms value of the line-to-line
voltage VLL at the connection to the
grid is 3.3 kV.
• The power produced by the tidal
generator is not constant, but
changes periodically over time.
• The developed control system of the
electric drive adjusts to the variating
power and remains stable during the
whole operation.
Yujing [email protected]
