C-GEN Direct Drive PTO

Overview

The C-GEN generator is a novel direct drive linear generator which is easy to manufacture and assemble, as well as being theoretically 85-90% efficient over a wide range of loads from part to full load. This is greater than competing PTOs such as hydraulics, and hence the PTO could offer an opportunity to enable greater annual energy yields.

A number of prototypes ranging in scale from 15 kW to 1 MW have previously been demonstrated to confirm the scientific and technical rigour of the concept, including a 50kW prototype for wave energy applications. Developments for wave energy during this project include testing of components (electrical windings and bearings) in flooded conditions, using a large-scale, representitive test system.

During the project, a significant improvement in thermal performance was achieved and the bearing design was increase the reliability and robustness of bearings for linear generators. All previous developments had taken place in the lab, with experiments in realistic environments, but the deployment in Stage 3 advanced the readiness of this solution to a stage where it could subsequently now be deployed in a WEC system.

Another focus of the project was on understanding how generator windings and bearings perform under marinisation. Results from modelling and testing fed into the design tool to be used for full scale designs of existing wave devices, to demonstrate this technology may be able to support low energy costs for the whole wave energy system.