Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter
The Wavestar Wave Energy Converter (WEC) is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO) system, converting the wave induced motion of the floats into a steady power output to the grid....
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2013-08-01
|
| Series: | Energies |
| Subjects: | |
| Online Access: | http://www.mdpi.com/1996-1073/6/8/4001 |
| _version_ | 1798006017755185152 |
|---|---|
| author | Enrique Vidal Rico H. Hansen Morten M. Kramer |
| author_facet | Enrique Vidal Rico H. Hansen Morten M. Kramer |
| author_sort | Enrique Vidal |
| collection | DOAJ |
| description | The Wavestar Wave Energy Converter (WEC) is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO) system, converting the wave induced motion of the floats into a steady power output to the grid. In the present work, a PTO based on a novel discrete displacement fluid power technology is explored for the Wavestar WEC. Absorption of power from the floats is performed by hydraulic cylinders, supplying power to a common fixed pressure system with accumulators for energy smoothing. The stored pressure energy is converted into electricity at a steady pace by hydraulic motors and generators. The storage, thereby, decouples the complicated process of wave power absorption from power generation. The core for enabling this PTO technology is implementing a near loss-free force control of the energy absorbing cylinders. This is achieved by using special multi-chambered cylinders, where the different chambers may be connected to the available system pressures using fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC) is created, allowing near loss free discrete force control. This paper presents a complete PTO system for a 20 float Wavestar based on the DDC. The WEC and PTO is rigorously modeled from incident waves to the electric output to the grid. The resulting model of +600 states is simulated in different irregular seas, showing that power conversion efficiencies above 70% from input power to electrical power is achievable for all relevant sea conditions. |
| first_indexed | 2024-04-11T12:48:14Z |
| format | Article |
| id | doaj.art-217659e745e2427e9ff4c46930bcc685 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-11T12:48:14Z |
| publishDate | 2013-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-217659e745e2427e9ff4c46930bcc6852022-12-22T04:23:16ZengMDPI AGEnergies1996-10732013-08-01684001404410.3390/en6084001Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy ConverterEnrique VidalRico H. HansenMorten M. KramerThe Wavestar Wave Energy Converter (WEC) is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO) system, converting the wave induced motion of the floats into a steady power output to the grid. In the present work, a PTO based on a novel discrete displacement fluid power technology is explored for the Wavestar WEC. Absorption of power from the floats is performed by hydraulic cylinders, supplying power to a common fixed pressure system with accumulators for energy smoothing. The stored pressure energy is converted into electricity at a steady pace by hydraulic motors and generators. The storage, thereby, decouples the complicated process of wave power absorption from power generation. The core for enabling this PTO technology is implementing a near loss-free force control of the energy absorbing cylinders. This is achieved by using special multi-chambered cylinders, where the different chambers may be connected to the available system pressures using fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC) is created, allowing near loss free discrete force control. This paper presents a complete PTO system for a 20 float Wavestar based on the DDC. The WEC and PTO is rigorously modeled from incident waves to the electric output to the grid. The resulting model of +600 states is simulated in different irregular seas, showing that power conversion efficiencies above 70% from input power to electrical power is achievable for all relevant sea conditions.http://www.mdpi.com/1996-1073/6/8/4001wave energyPTOWavestarhydraulicsWEC |
| spellingShingle | Enrique Vidal Rico H. Hansen Morten M. Kramer Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter Energies wave energy PTO Wavestar hydraulics WEC |
| title | Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter |
| title_full | Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter |
| title_fullStr | Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter |
| title_full_unstemmed | Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter |
| title_short | Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter |
| title_sort | discrete displacement hydraulic power take off system for the wavestar wave energy converter |
| topic | wave energy PTO Wavestar hydraulics WEC |
| url | http://www.mdpi.com/1996-1073/6/8/4001 |
| work_keys_str_mv | AT enriquevidal discretedisplacementhydraulicpowertakeoffsystemforthewavestarwaveenergyconverter AT ricohhansen discretedisplacementhydraulicpowertakeoffsystemforthewavestarwaveenergyconverter AT mortenmkramer discretedisplacementhydraulicpowertakeoffsystemforthewavestarwaveenergyconverter |