With the recent sharp increases in the price of oil, issues of security of supply, and pressure to honor greenhouse gas emission limits (e.g., the Kyoto protocol), much attention has turned to renewable energy sources to fulfill future increasing energy needs. Wind energy, now a mature technology, has had considerable proliferation, with other sources, such as biomass, solar, and tidal, enjoying somewhat less deployment. Waves provide previously untapped energy potential, and wave energy has been shown to have some favorable variability properties (a perennial issue with many renewables, especially wind), especially when combined with wind energy [1].

/pdf/energy-maximizing-control-of-wave-energy-converters-the-56go405abj.pdf

Energy-Maximizing Control of Wave-Energy Converters: The Development of Control System Technology to Optimize Their Operation

Nowadays, harvesting energy from vibration is one of the most promising technologies. However, the majority of current researches obtain 10 µW to 100 mW power, which has only limited applications in self-powered wireless sensors and low-power electronics. In fact, the vibrations in some situations can be very large, for example, the vibrations of tall buildings, long bridges, vehicle systems, railroads, ocean waves, and even human motions. With the global concern on energy and environmental issues, energy harvesting from large-scale vibrations is more attractive and becomes a research frontier. This article is to provide a timely and comprehensive review of the state-of-the-art on the large-scale vibration energy harvesting, ranging from 1 W to 100 kW or more. Subtopics include energy assessment from large vibrations, piezoelectric materials and electromagnetic transducers, motion transmission and magnification mechanisms, power electronics, and vibration control. The relevant applications discussed in th...

Large-scale vibration energy harvesting

Ocean waves are a promising source of renewable energy In this paper, we briefly introduce the characteristics of ocean wave energy and summarize the principles of harvesting ocean energy by wave 

/pdf/review-of-control-strategies-for-wave-energy-conversion-2zougsa133.pdf

Review of control strategies for wave energy conversion systems and their validation: the wave-to-wire approach

https://pure.hw.ac.uk/ws/files/22846703/Ning_Zou_OWC_HOBEM_Energy_Accepted_manuscript_Energy2015.pdf

Investigation of hydrodynamic performance of an OWC (oscillating water column) wave energy device using a fully nonlinear HOBEM (higher-order boundary element method)

This paper presents results of the Reference Model Project (RMP), which began five years ago to facilitate Marine Energy Conversion (MEC)

Methodology for design and economic analysis of marine energy conversion (mec) technologies.

Wave energy has the potential to be a major provider of renewable energy, especially in the UK. However, there is the major problem of producing efficient devices for a wide variety of sites with different operating conditions. This article addresses the time domain modelling of a heaving point absorber connected to a hydraulic power take-off (PTO) unit in regular waves. Two cases for the hydraulic PTO unit are considered: an ideal model and a model containing losses. Component losses are included to give a more accurate prediction of the maximum power pro- duction and to discover if the parameters to optimize the device change when losses are included. The findings show that both cases are optimized by varying the size of the hydraulic motor and the optimal size is only dependent on wave period and the trend is the same for both cases. Results also showed that to maximize the power produced for both cases, there is an optimal force that the unit produces, which can be derived from theory. Finally, power reduction as a result of the hydraulic losses is also observed with efficiencies reducing at larger wave heights.

https://journals.sagepub.com/doi/pdf/10.1177/0957650911407818

Determination of optimal parameters for a hydraulic power take-off unit of a wave energy converter in regular waves

https://purehost.bath.ac.uk/ws/files/143200473/CargoR2_clean.pdf

Strategies for active tuning of Wave Energy Converter hydraulic power take-off mechanisms

The optimisation of a wave energy converter hydraulic power take-off for sea states of varying wave amplitude, direction and frequency is a significant problem. Sub-optimal configuration can result in very inefficient energy conversion, so understanding the design trade-offs is key to the success of the technology. This work focuses on a generic point absorber type wave energy converter. Previous work by the authors has considered the optimisation of this device for regular waves to gain an understanding of the fundamental issues. This work extends the analysis to the more realistic case of irregular waves. Simulations are performed using an irregular wave input to predict how the power take-off will operate in real sea conditions. Work is also presented on a motor speed control strategy to maintain the maximum flow of electrical power to the grid, assuming the use of a doubly fed induction generator. Finally, the sizing of key components in the power take-off is considered in an attempt to maximise power take-off efficiency and generated power.

/pdf/optimisation-and-control-of-a-hydraulic-power-take-off-unit-3eyv4zznvg.pdf

Christopher Cargo

Papers

Determination of optimal parameters for a hydraulic power take-off unit of a wave energy converter in regular waves

Strategies for active tuning of Wave Energy Converter hydraulic power take-off mechanisms

Optimisation and control of a hydraulic power take-off unit for a wave energy converter in irregular waves:

Optimal design of a realistic hydraulic power take-off in irregular waves

Power Transmissions for Wave Energy Converters: A Review