Annette von Jouanne

Ocean wave energy overview and research at Oregon State University

The solutions to todays energy challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse national energy resource plan. An extremely abundant and promising source of energy exists in the worlds oceans. Ocean energy exists in the forms of wave, tidal, marine currents, thermal (temperature gradient) and salinity. Among these forms, significant opportunities and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the motion of the ocean waves, and converting that motion into electrical energy. This paper presents the fundamentals of ocean wave energy, and also a summary of the wave energy research being conducted at Oregon State University. This paper is intended to serve as an introduction to wave energy for scientists and engineers, particularly those with a wind energy background.

Comparison of Direct-Drive Power Takeoff Systems for Ocean Wave Energy Applications

This paper presents a comprehensive power takeoff (PTO) analysis program conducted as a collaborative research effort between Columbia Power Technologies, Inc., Oregon State University (OSU), and the U.S. Navy. Eighteen different direct-drive technologies were evaluated analytically and down-selected to five promising designs. Each of the five prototypes was simulated, modeled in SolidWorks, and built at the 200-W peak level and tested on OSUs wave energy linear test bed. The simulations were validated with the 200-W experimental results and then scaled up to 100 kW, with full 100-kW designs including costs, maintenance, operations, etc., to estimate the cost of energy (COE) for each PTO buoy system at utility scale.

Numerical Modeling and Ocean Testing of a Direct-Drive Wave Energy Device Utilizing a Permanent Magnet Linear Generator for Power Take-Off

For the past several years an inter-disciplinary research group at Oregon State University (OSU), working in conjunction with Columbia Power Technologies (CPT) has been researching innovative direct-drive wave energy systems. These systems simplify the conversion of wave energy into electricity by eliminating intermediate energy conversion processes. In support of this research OSU and CPT have developed a hybrid numerical/physical modeling approach utilizing a large scale linear test bed (LTB), and a commercial coupled analysis tool. This paper will present an overview of this modeling approach and its application to the design of a 10kW prototype wave energy conversion system that was tested in the open ocean in the fall of 2008. The data gathered during ocean testing was used to calibrate the numerical model of the device and predict the energy capture potential of the system.Copyright

A DSP Controlled resonant active filter for power conditioning in three-phase industrial power systems

This paper presents a DSP controlled resonant active filter for power conditioning in three-phase industrial or commercial power systems. The active filter is designed to cancel lower-order harmonics generated by nonlinear loads using a series resonant LC tank tuned to a high frequency along with a pulse-width modulated (PWM) rectifier topology. The PWM control of the active filter allows for independent control of lower-order harmonics to efficiently cancel load-generated harmonics for power quality improvement. The active filter control algorithm is simulated in MATLAB and the real-time harmonic cancellation process is implemented on a DSP and verified through experimental results.

A novel permanent magnet tubular linear generator for ocean wave energy

This paper presents a novel permanent magnet tubular linear generator (PMTLG) buoy system designed to convert the linear motion of the ocean waves into electrical energy. The design incorporates no working seals and a salt water airgap bearing surface integration between PMTLG buoy components. The internal generator design will be discussed, in addition to the system integration with the buoy structure and the linear test bed performance results.

Supercapacitor energy storage for wind energy integration

The fast growth of wind energy utilization has necessitated research on wind energy integration. Due to the variable nature of wind and the forecasting challenges, it is desirable to utilize wind energy alongside energy storage sources for reliable wind energy integration. This paper details the design of a supercapacitor storage system that is integrated into an in-lab grid that was developed to research methods aimed at optimizing energy production while increasing the predictability of wind farm outputs. The in-lab grid features the emulation of several high-power grid sources and loads including a wind farm, energy storage systems and hydro resources. Results include the storage system simulations generated from a variety of AGC algorithms run on a dSPACE rapid prototyping machine. In addition, this paper presents a model for a supercapacitor developed to be used in characterization and lifetime tests. These tests are useful in predicting performance of the system for purposes of ensuring its efficient and safe use. Results validating the model and estimating the expected performance of the system are presented.

Wave Energy Converter with wideband power absorption

Wave energy possesses a wide frequency range for many real-world ocean locations compared to the power absorption or capture range for some proposed Wave Energy Converter (WEC) systems. Many ocean sites possess waves with a rich frequency content due either to random sea or inshore effects. This paper first demonstrates the potential missed energy extraction opportunities at three different ocean sites using the buoy parameters from a previously built WEC that utilizes an optimal control scheme. It then introduces several control strategies in the literature, in addition to a proposed wide bandwidth control strategy, and compares the amount of relative power absorption of the WEC. The proposed controller does not require acceleration feedback and can be realized with only position feedback. The design of the proposed controller is discussed and then the power absorption results are compared to optimal and other wave energy capture schemes.

Numerical and Experimental Analysis of a Novel Wave Energy Converter

A novel point absorber wave energy converter (WEC) is being developed by Columbia Power Technologies, LLC (CPT). Numerical and physical experiments have been performed by Columbia Power, Garrad Hassan and Partners (GH) and Oregon State University (OSU). Three hydrodynamic modeling tools including WAMIT, GH WaveFarmer, and OrcaFlex are used to evaluate the performance of the WEC. GH WaveFarmer is a specialized numerical code being developed specifically for the wave energy industry. Performance and mooring estimates at full scale were initially evaluated and optimized, which were then followed by the development of a 1/33rd scale physical model to obtain comparable datasets, aiming to validate the predictions and reduce the uncertainty associated with other numerical model results. The tests of the 1/33rd scale model of the CPT WEC were recently carried out at the multi-directional wave basin of the O.H. Hinsdale Wave Research Laboratory (HWRL), in conjunction with the Northwest National Marine Renewable Energy Center (NNMREC) at OSU. This paper presents details of the modeling program and progress to date. Emphasis is given to the coupling of WAMIT with GH WaveFarmer for performance estimates and the coupling of WAMIT with the OrcaFlex model for mooring load estimates. An overview of the novel 3-body WEC, including operation and mooring system, is also presented. The 1/33rd scale model functionality is described including an overview of the experimental setup at the basin. Comparisons between the numerical and experimental results are shown for both regular and irregular waves and for several wave headings and dominant directions using a number of spreading functions. The paper concludes with an overview of the next steps for the modeling program and future experimental test plans.Copyright

A novel ocean sentinel instrumentation buoy for wave energy testing

This paper presents a novel Ocean Sentinel instrumentation buoy that the Northwest National Marine Renewable Energy Center (NNMREC) has developed with AXYS Technologies for the testing of wave energy converters (WECs). NNMREC is a Department of Energy-sponsored partnership among Oregon State University (OSU), the University of Washington (UW), and the National Renewable Energy Laboratory (NREL). The Ocean Sentinel instrumentation buoy is a surface buoy based on the 6-m NOMAD (Navy Oceanographic Meteorological Automatic Device) design. The Ocean Sentinel provides power analysis, data acquisition, and environmental monitoring, as well as an active converter interface to control power dissipation to an onboard electrical load. The WEC being tested and the instrumentation buoy are moored with approximately 125 meters separation; connected by a power and communication umbilical cable. The Ocean Sentinel was completed in 2012 and was deployed for the testing of a WEC at the NNMREC open-ocean test site, north of Newport, OR, during August and September of 2012.

High Resolution Wave Tank Testing of Scaled Wave Energy Devices

In many industries, such as the wave energy industry, the importance of accurate physical model testing in the development process to full scale devices cannot be overemphasized. This paper presents a new, high-precision wave tank testing system and process designed and implemented by Columbia Power Technologies (CPT) and Oregon State University (OSU). The system’s high level of functionality was demonstrated during characterization of CPT’s wave energy converter (WEC) and is now established at OSU’s O.H. Hinsdale Wave Research Laboratory (HWRL), in collaboration with the Northwest National Marine Renewable Energy Center (NNMREC) headquartered at OSU. The critical instrumentation, optical motion tracking system, data acquisition and related components developed for wave tank testing are fully characterized herein, and the paper concludes with example testing of a scaled wave energy device including experimental results.Copyright