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Charlottesville, VA, United States

Amon E.A.,Oregon State University | Brekken T.K.A.,Oregon State University | Schacher A.A.,Columbia Power Technologies, Llc
IEEE Transactions on Industry Applications | Year: 2012

Many forms of renewable energy exist in the world's oceans, with ocean wave energy showing great potential. However, the ocean environment presents many challenges for cost-effective renewable energy conversion, including optimal control of a wave energy converter (WEC). This paper presents a maximum power point tracking (MPPT) algorithm for control of a point absorber WEC. The algorithm and testing hardware are presented in detail, as well as simulated and laboratory test results. The results show that MPPT applied to ocean wave energy is an effective and promising control strategy. © 2012 IEEE. Source

Brekken T.K.A.,Oregon State University | Hapke H.M.,Oregon State University | Stillinger C.,Oregon State University | Prudell J.,Columbia Power Technologies, Llc
IEEE Transactions on Energy Conversion | Year: 2010

The objective of this paper is to analyze, test, and compare machines and drives in oscillating applications. In particular, this paper is focused on low-power wave energy generator applications, such as autonomous weather and monitoring buoys with power requirements in the 100 W and less range. Due to the oscillating motion of waves, the ocean environment can require bidirectional and variable speed operation of the generator. In this research, the efficiency of a set of small brushed dc, induction, brushless dc, and synchronous reluctance drives and machines were compared in constant and oscillating operation. The presented results show that drives and machines used in low-power oscillating applications (e.g., ocean wave energy) should not expect a significant derating with respect to their nameplate rating. In addition, it is shown that the frequency of oscillation (e.g., ocean wave frequency) has little impact on efficiency. © 2006 IEEE. Source

Prudell J.,Columbia Power Technologies, Llc | Stoddard M.,Oregon State University | Stoddard M.,CVO Electrical Systems LLC | Amon E.,Oregon State University | And 2 more authors.
IEEE Transactions on Industry Applications | Year: 2010

This paper presents a novel permanent-magnet tubular linear generator (PMTLG) buoy system designed to convert the linear motion of ocean waves into electrical energy. The design incorporates no working seals and a saltwater air-gap bearing surface integration between the PMTLG buoy components. The internal generator design will be discussed, in addition to the system integration with the buoy structure. The simulation and hardware results of the generator are presented. © 2006 IEEE. Source

An apparatus and corresponding method for maintaining an air gap between a stator and rotor in an electro-mechanical energy converter is provided. The apparatus includes a structural sleeve and a plurality of stator sections attached to an inner surface of the structural sleeve. A hub is enclosed by the structural sleeve and is concentric with the structural sleeve. A plurality of rotor sections is flexibly coupled to the hub and is enclosed by the structural sleeve. A rail system is positioned within the structural sleeve and is concentric with the structural sleeve. The rail system guides the rotor sections in a substantially circular path and defines an air gap between the plurality of stator sections and plurality of rotor sections.

Columbia Power Technologies, Llc | Date: 2013-09-30

An apparatus and method for converting wave energy using the relative rotational movement between two interconnected float assemblies and the relative rotational movement between each of the float assemblies and a spar which extends from a buoyant nacelle having a central longitudinal axis wherein the floats are nestable behind the buoyant nacelle.

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