Photo: IMAGINE test rig and mounting of EMG prototype at VGA facility (Courtesy of IMAGINE)

IMAGINE consortium makes progress on wave electro-mechanical PTO

The IMAGINE project consortium has made headway on the manufacturing and assembly of the Electro-Mechanical Generator (EMG) power take-off (PTO) concept and the test rig, along with other project assessments and deliverables.

Photo showing the EMG prototype in the assembly area at UmbraGroup's facility (Courtesy of IMAGINE)
The EMG prototype in the assembly area at UmbraGroup’s facility (Courtesy of IMAGINE)

Backed by Horizon 2020 funding, and project leader UmbraGroup’s expertise in advanced aerospace engineering, the IMAGINE project seeks to develop and demonstrate the EMG PTO concept for various wave energy device types.

Aside from UmbraGroup, the project consortium is made up of The University in Edinburgh, Bureau Veritas, Norges Teknisk-Naturvitenskapelige Universitet (NTNU), Cruz Atcheson Consulting Engineers, and engineering company VGA.

Based on realistic requirements for wave energy devices, the project will design and fabricate a 250kW prototype for performance and lifetime bench testing to prove that the system can meet cost reduction and performance improvement targets, according to UmbraGroup.

Manufacturing and assembly of EMG and the test rig

After the selection of the optimum EMG design, the EMG prototype has been manufactured at the UMBRAGROUP facility in Foligno in Italy.

Computer Numerical Control (CNC) machines have been used for manufacturing components such as the screw shaft and nut, at Foligno’s production facility. Steel balls have been supplied by the facility in Eltmann in Germany, and the generator has been produced in the R&D Center’s workshop.

All the key components of the EMG have been manufactured in the UMBRAGROUP’s facilities to ensure the highest priority and guarantee the quality of the production, according to the project.

Photo showing the IMAGINE test rig and mounting of EMG prototype at VGA facility (Courtesy of IMAGINE)
IMAGINE test rig and mounting of EMG prototype at VGA facility (Courtesy of IMAGINE)

VGA modelled the test rig main components to validate its conceptual architecture and identify the relevant load cases, later assessed in the detailed design phase.

The manufacturing activities have been completed and the test rig set-up is currently assembled at VGA in Deruta in Italy, where the HardWare-In-the-Loop testing will be performed.

Project assessments and deliverables

After conversations with the project consortium and the project officer, the decision was made that K2 Management would update the wave energy converter (WEC) model to reflect the updated design specifications.

This led to additional and updated design load cases (DLCs) for the HardWare-In-the-Loop tests, according to IMAGINE.

In addition, NTNU further investigated Model Predictive Control (MPC) techniques for the EMG in different sea states and compared this with other control strategies. The study showed that a simplified and easy-to-use (non-linear) model could be identified from simulation data of a high fidelity EMG model.

The former was then used for the predictive controller, making the optimization of the future control outputs possible in short time and achieving, in general, better performance than other control strategies, IMAGINE project consortium informed.

The significant reduction in the computational time used by the MPC controller, made the proposed design promising for future implementations in real-time simulation, while keeping a relatively high predictions quality, according to IMAGINE.

The Policy and Innovation Group at the University of Edinburgh has performed the socio-economic, techno-economic and environmental impact assessments of the EMG PTO to support the business case.

Different case studies have been assessed to investigate the potential gross value added (GVA) to Europe from wave energy deployment with the EMG PTO, to assess the potential reductions in cost of energy of wave energy with the EMG PTO, and to evaluate the global warming potential (carbon equivalent emissions/energy produced).

A selection of these results will be presented in upcoming online conferences and in journals, according to IMAGINE project consortium.