A new passivity-based nonlinear causal control technique for wave energy converters with finite stroke

Journal Article · Thu Aug 29 00:00:00 EDT 2019 · Proceedings of the American Control Conference (ACC)

DOI:https://doi.org/10.23919/acc.2019.8814906· OSTI ID:1856258

Scruggs, Jeffrey T. ^[1]; Lao, Yejun ^[2]

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1. Univ. of Michigan, Ann Arbor, MI (United States); Re Vision Consulting
2. Univ. of Michigan, Ann Arbor, MI (United States)

A new technique is proposed for the design of nonlinear causal feedback controllers for wave energy converters, which explicitly protect against stroke saturation. Here, the technique is an improvement of a technique originally proposed. The primary challenge associated with the problem is the design of nonlinear controllers for which global closed-loop stability can be assured with probability 1 for stationary stochastic response, without also unduly sacrificing power generation performance. The proposed technique consists of three steps: 1) designing a linear feedback controller using multi-objective optimization techniques; 2) augmenting this design with an extra input channel that adheres to a closed-loop passivity condition; and 3) designing an outer, nonlinear passive feedback loop that controls this augmented input in such a way as to ensure stroke limits are maintained. The primary contribution of this paper is a fundamental improvement to the second of these steps, for which the previous technique was not guaranteed to return a valid solution. The proposed technique, by contrast, is shown to always produce a nonlinear controller with the desired properties, under very general modeling assumptions. The technique is illustrated on a simple heaving-buoy wave energy converter example.

• Research Organization: Re Vision Consulting, LLC, Sacramento, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Water Power Technologies Office
• Grant/Contract Number: EE0007173; EE0008099
• OSTI ID: 1856258
• Journal Information: Proceedings of the American Control Conference (ACC), Journal Name: Proceedings of the American Control Conference (ACC) Vol. 2019; ISSN 0743-1619
• Publisher: IEEE
• Country of Publication: United States
• Language: English

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