Modeling, Control Strategy, and Power Conditioning for Direct-Drive Wave Energy Conversion to Operate With Power Grid

The direct-drive wave energy conversion (WEC) system adopts direct-drive power takeoff technique and the linear permanent magnet generate (LPMG) is coupled directly to the floater, which leads to simple configuration and high efficiency. This type of device usually has common features in term of structure, model, optimal control strategy, and power conditioning. Taking the AWS as the example, the models of the direct-drive WEC are first presented, and recommendations are also proposed for their applications. To extract maximum power from the wave, the AWS has to be regulated in resonance with the wave. Different types of control strategy using mechanical and electrical devices have been developed. Their features and applications are compared and discussed. An optimal control strategy, which enables AWS extracting maximum power from the irregular wave, is proposed. Since the floater reciprocates, not only the magnitude but also the direction of the translator motion speed changes. In this condition, the frequency, terminal voltage, and output active power of the LPMG vary. These features may not satisfy the requirements of the grid code for the integration of wave generation into power grid. Hence, the power conditioner is very important for the integration of the AWS into the power grid. The power conditioners are developed to integrate the AWS into the power grid, and the application of the energy storage in smoothing the output power of the AWS is also studied.

[1]  Duarte Valério,et al.  Optimisation of wave energy extraction with the Archimedes Wave Swing , 2007 .

[2]  P. Kundur,et al.  Power system stability and control , 1994 .

[3]  H. Polinder,et al.  Linear PM Generator system for wave energy conversion in the AWS , 2004, IEEE Transactions on Energy Conversion.

[4]  M G de Sousa Prado,et al.  Modelling and test results of the Archimedes wave swing , 2006 .

[5]  Hiroyuki Osawa,et al.  The open sea tests of the offshore floating type wave power device "Mighty Whale" -characteristics of wave energy absorption and power generation , 2001, MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295).

[6]  Jonathan Shek,et al.  Experimental verification of linear generator control for direct drive wave energy conversion , 2010 .

[7]  Nick J. Baker,et al.  Direct drive electrical power take-off for offshore marine energy converters , 2005 .

[8]  Pragasen Pillay,et al.  Modeling of permanent magnet motor drives , 1988 .

[9]  Mike Barnes,et al.  Power quality and stability improvement of a wind farm using STATCOM supported with hybrid battery energy storage , 2006 .

[10]  M. N. Sahinkaya,et al.  A review of wave energy converter technology , 2009 .

[11]  M. Leijon,et al.  Multiphysics simulation of wave energy to electric energy conversion by permanent magnet linear generator , 2005, IEEE Transactions on Energy Conversion.

[12]  B. Das,et al.  Voltage control performance of AWS connected for grid operation , 2006, IEEE Transactions on Energy Conversion.

[13]  Jonathan Shek,et al.  Reaction force control of a linear electrical generator for direct drive wave energy conversion , 2007 .

[14]  Ross Henderson,et al.  Design, simulation, and testing of a novel hydraulic power take-off system for the Pelamis wave energy converter , 2006 .

[15]  J. Sa da Costa,et al.  Modeling of an ocean waves power device AWS , 2003, Proceedings of 2003 IEEE Conference on Control Applications, 2003. CCA 2003..

[16]  Duarte Valério,et al.  Identification and control of the AWS using neural network models , 2008 .

[17]  N. H. Clark,et al.  Technologies for energy storage. Flywheels and super conducting magnetic energy storage , 2000, 2000 Power Engineering Society Summer Meeting (Cat. No.00CH37134).

[18]  Henk Polinder,et al.  Design, modelling and test results of the AWS PM linear generator , 2005 .

[19]  Markus Mueller,et al.  Power Conditioning of the Output from a Linear Vernier Hybrid Permanent Magnet Generator for using Direct Drive Wave Energy Converters , 2005 .

[20]  G. Joos,et al.  Impact and Control of Energy Storage Systems in Wind Power Generation , 2007, 2007 Power Conversion Conference - Nagoya.

[21]  Nick J. Baker,et al.  Modelling the performance of the vernier hybrid machine , 2003 .

[22]  A. Clément,et al.  Wave energy in Europe: current status and perspectives , 2002 .

[23]  Masuo Goto,et al.  Power system stability improvement by energy storage type STATCOM , 2003, 2003 IEEE Bologna Power Tech Conference Proceedings,.

[24]  Paulo Alexandre Justino,et al.  OWC wave energy devices with air flow control , 1999 .

[25]  Peter Frigaard,et al.  Prototype Testing of the Wave Energy Converter Wave Dragon , 2006 .

[26]  J.P. Barton,et al.  Energy storage and its use with intermittent renewable energy , 2004, IEEE Transactions on Energy Conversion.

[27]  Mats Leijon,et al.  Hydrodynamic modelling of a direct drive wave energy converter , 2005 .

[28]  Ping Ju,et al.  Optimal Control for AWS-Based Wave Energy Conversion System , 2009, IEEE Transactions on Power Systems.

[29]  Markus Mueller,et al.  Electrical generators for direct drive wave energy converters , 2002 .

[30]  M. Chinchilla,et al.  Control of permanent-magnet generators applied to variable-speed wind-energy systems connected to the grid , 2006, IEEE Transactions on Energy Conversion.

[31]  P.E. Mercado,et al.  Control Design and Simulation of DSTATCOM with Energy Storage for Power Quality Improvements , 2006, 2006 IEEE/PES Transmission & Distribution Conference and Exposition: Latin America.

[32]  A. Clément,et al.  Optimal Latching Control of a Wave Energy Device in Regular and Irregular Waves , 2006 .

[33]  Xiao-Ping Zhang,et al.  Modeling and Control of AWS-Based Wave Energy Conversion System Integrated Into Power Grid , 2008, IEEE Transactions on Power Systems.