Overview of modelling and control strategies for wind turbines and wave energy devices: Comparisons and contrasts

Increasingly, there is a focus on utilising renewable energy resources in a bid to fulfil increasing energy requirements and mitigate the climate change impacts of fossil fuels. While most renewable resources are free, the technology used to usefully convert such resources is not and there is an increasing focus on improving the conversion economy and efficiency. To this end, advanced control technology can have a significant impact and is already a relatively mature technology for wind turbines. Though wave energy systems are still in their infancy, significant benefits have been shown to accrue from the appropriate use of control technology. To date, the application communities connected with wind and wave energy have had little communication, resulting in little cross fertilisation of control ideas and experience, particularly from the more mature wind area to wave. This paper examines the application of control technology across both domains, both from a comparative and contrasting point of view, with the aim of identifying commonalities in control objectives and potential solutions. Key comparative reference points include the articulation of the stochastic resource models, specification of control objectives, development of realistic device models, and development of solution concepts. Not least, in terms of realistic system requirements are the set of physical and legislative constraints under which such renewable energy systems must operate, and the need to provide reliable and fault-tolerant control solutions, which respect the often remote and relatively inaccessible location of many offshore deployments.