A new method of random time-series simulation

IEEE Trans. Sustain. Energy

2013

160

157

Abstract-A novel strategy for the real-time control of oscillating wave energy converters (WECs) is proposed. The controller tunes the oscillation of the system such that it is always in phase with the wave excitation force and the amplitude of the oscillation is within given constraints. Based on a nonstationary, harmonic approximation of the wave excitation force, the controller is easily tuned in real-time for performance and constraints handling, through one single parameter of direct physical meaning. The effectiveness of the proposed solution is assessed for a heaving system in one degree of freedom, in a variety of irregular (simulated and real) wave conditions. A performance close to reactive control and to model predictive control is achieved. Additional benefits in terms of simplicity and robustness are obtained.

Section: A Wave Datamentioning

confidence: 99%

A Simple and Effective Real-Time Controller for Wave Energy Converters

IEEE Trans. Sustain. Energy

2013

160

157

“…The peak frequency is varied from 0.3 to 1.2 rad/s, with step 0.05, the significant wave heights are 0.5, 1, 2, and 4 m, and ¼ 5 (not important for the purposes of this study; the reader may refer to [8] to verify how the bandwidth affects the highlevel control strategy). Random-wave time-series of 7200 s, sampled at 2.56 Hz, are generated for each simulation, from S ð!Þ, based on the method proposed in [26] and also described in [8]. Fig.…”

Section: A Wave Datamentioning

confidence: 99%

Hierarchical Robust Control of Oscillating Wave Energy Converters With Uncertain Dynamics

IEEE Trans. Sustain. Energy

2014

Abstract-Energy-maximizing controllers for wave energy devices are normally based on linear hydrodynamic device models. Such models ignore nonlinear effects which typically manifest themselves for large device motion (typical in this application) and may also include other modeling errors. The effectiveness of a controller is, in general, determined by the match between the model the controller is based on and the actual system dynamics. This match becomes especially critical when the controller is highly tuned to the system. In this paper, we present a methodology for reducing this sensitivity to modeling errors and nonlinear effects by the use of a hierarchical robust controller, which shows small sensitivity to modeling errors, but allows good energy maximization to be recovered through a passivity-based control approach.

“…The peak frequency is varied from 0.3 to 1.2 rad/s, with step 0.05, the significant wave heights are 0.5, 1, 2 and 4 m, and λ = 5 (not important for the purposes of this study; the reader may refer to [8] to verify how the bandwidth affects the high-level control strategy). Random-wave time series of 7200s, sampled at 2.56Hz, are generated for each simulation, from S ηη (ω), based on the method proposed in [25] and also described in [8].…”

Section: A Wave Datamentioning

confidence: 99%

Robust control of wave energy converters

2014 IEEE Conference on Control Applications (CCA)

2014

Abstract-Energy-maximising controllers for wave energy devices are normally based on linear hydrodynamic device models. Such models ignore nonlinear effects which typically manifest themselves for large device motion (typical in this application) and may also include other modelling errors. In this paper, we present a methodology for reducing the sensitivity to modelling errors and nonlinear effects by the use of a hierarchical robust controller, which also allows good energy maximisation to be recovered through a passivity-based control approach.