EDRIVE-MEC: All Electric Drive Train for Marine Energy Converters Conversion of energy from wave into electricity is ideally performed by a PTO and power conditioning system that can convert motion in multiple directions, react large forces or torques whilst operating at low velocity, variable voltage and frequency, with high reliability, availability and efficiency over a wide range of loads. All aspects of this demanding specification contribute directly to the Life Time Cost of Energy and hence economic feasibility of devices. At present no single PTO technology that has been demonstrated is able to meet this specification for wave energy. The two main options for the PTO used in a wave device: hydraulics and direct drive. Wave device developers have focussed on using hydraulics as the PTO, whether it be high pressure oil or water (Pelamis, Aquamarine). In discussions with our industrial partners we learnt that the only reason for using hydraulics was due its availability off the shelf, but all partners were concerned about the limitations including, low efficiency at part load; ability to control over a wide range of frequencies; and displacement leading to potential end-stop problems. The alternative to hydraulics is direct drive, in which the mechanical interface is eliminated, but now the generator has to operate at low velocity and high force. Direct drive systems have been proven through lab tests at Durham and Edinburgh, and through sea trials by Uppsala in Sweden, Archimedes Wave Swing and Oregon State University. In each of these cases a permanent magnet synchronous machine has been used and the generator has been of a linear planar or tubular topology. Energy can only be taken out of the device from motion in one direction, principally heave, whereas devices surge and pitch as well as heave. The use of linear generators in their current form has constrained the functionality of direct drive power take off systems, as it has not allowed energy to be converted from more than one motion. No consideration has been given to speed enhancing techniques, such as magnetic gear boxes, as developed at Sheffield for rotary machines, or the use of springs, either internally produced through control, or external physical springs, such as air springs. Speed enhancing allows a more optimised machine design, resulting in a reduction in physical size and an increase in efficiency. Previous work in direct drive power take off has proved the concept will work, but solutions are not fully optimised, designed for reliability or matched to the characteristics of the wave device. As with the generator, developers have proved the concept of connecting direct drive systems to the grid, but making use of conventional power converter approaches. However, it is well known that there is a reliability issue with power converters in the wind industry, and in the tidal sector developers use an onshore power converter for easy access. The main cause of faults within the power converter is the continuous thermal cycling due to the variable nature of wind and wave. There is therefore an opportunity to investigate alternative power converter solutions, such as multi-level systems, where the stress on the power devices are now shared across a number of devices. The main aim of the project has been formulated in discussions with our industrial partners: develop an integrated electrical power take off system with non-mechanical speed enhancement, integrated and reliable flexible power electronics, providing adaptive control over a range of operating regimes, taking into account nominal and extreme load conditions. E-DRIVE proposes to fulfil this aim through the development of novel integrated low speed generators with speed enhancement and power converter topologies with associated control to replace hydraulic systems. In doing so we will mirror developments in all/more electric systems in automotive and aerospace.

The UK is at the forefront of the development, adoption and export of Offshore Renewable Energy (ORE) technologies: offshore wind (OW), wave and tidal energy. To sustain this advantage, the UK must spearhead research and innovation in ORE, which will accelerate its adoption and widen the applicability of these technologies. Many organisations across the industry-academia spectrum contribute to ORE research and development (R&D) co-ordination and the ORE Supergen hub strategy will take a leadership role, integrating with these activities to guide and deliver fundamental research to advance the ORE sector. The role of the Supergen ORE hub is to provide research leadership for the ORE community to enable transformation to future scale ORE. The hub will articulate the vision for the future scale ORE energy landscape, will identify the innovations required and the fundamental research needed to underpin the innovation. It will also generate the pathway for translation of research and innovation into industry practice, for policy adaptation and public awareness in order to support the increased deployment of ORE technologies, reducing energy costs while increasing energy security, reducing CO2 emissions and supporting UK jobs. The hub will work closely with the ORE Catapult (ORECAT) and become well-connected with industry, government, the wider research community in the UK and internationally. It will bring together these groups to assemble the expertise and experience to define and target the innovations, research and actions to achieve the ambitious energy transformation envisioned for the UK. The new Supergen ORE hub will continue to support and build on the existing internationally leading academic capacity within these three research areas (OW, wave and tidal technology), whilst also enabling shared learning on common research challenges. The ORE hub will build a multi-disciplinary, collaborative approach, which will bring benefits through the sharing of best practice and exploitation of synergy, support equality and diversity and the development of the next generation of research leaders. The hub strategy provides an overview of research and innovation priorities, which will be addressed through multiple routes but linked through the hub, with activities designed to stimulate alignment across the research community and industry sectors to maximise engagement with prioritised research challenges through and beyond the hub time-scale. These include: 1. Networking and engagement activities to bring the research community together with industry and other stakeholders to ensure research efforts within the community are aligned, complementary and remain inspired by or relevant to industry challenges. This will include support and development of the ECR community to ensure sustainability and promote EDI within the sector as a whole. Actions will also be taken to identify potential cross over research synergies and opportunities for transfer of research between sectors and disciplines, both within and external to ORE. Furthermore, a structured communication plan built around progress of the community towards the sector research challenges will promote exploitation and commercialisation. 2. A set of core research work packages addressing priority topics selected and structured to maximize progress towards the sector objectives and building on the cross cutting expertise of the co-director team. 3. Targeted use of flexible fund as seed-corn activity leading to projects aligned with, and in partnership with, the hub.