Dept. of Civil, Structural & Environmental Engineering
Control algorithm development for WaveRAM using a real-time hybrid test (RTHT) platform
Keywords: Optimal control; wave energy; renewable energy; real-time hybrid testing; hydrodynamics; oscillating system.
Extracting wave energy from the ocean has vast potential with equally significant challenges, largely due to survival difficulties, but also with generally low overall efficiencies in the conversion process of generating electricity. Optimal control techniques can offer an inexpensive solution to increasing efficiency, in comparison to installation and maintenance costs, since algorithms can be replaced and trialled remotely.
The research taking place here is to develop a suitable control algorithm for optimising power capture of the WaveRAM (WRAM) wave energy converter (WEC), invented by Swirl Generators Limited (SGL). It is intended that an algorithm can be developed suitable for sea deployment. Therefore some design constraints are immediately established. It must: 1) perform better than simple linear damping; 2) execute in real-time; 3) be insensitive to model inaccuracies. In order to verify the success of the control algorithm it should be ideally tested on a real WEC however due to cost limitations this is currently impossible.
Real-time hybrid testing (RTHT) offers an ideal compromise at a manageable scale. The RTHT framework provides the means of incorporating simulated dynamics of the WRAM and control algorithm with realistic scaled down components similar to those that would be used at full scale. Prior to this research TCD had established a generic RTHT system that can be adapted to any application. In order to use it for the WRAM application an additional test rig was needed that would emulate the WRAM’s dynamic behaviour, linking it to a physical power-take-off (PTO) system.
A new test rig has therefore been purpose-built for developing a control algorithm for the WRAM. The work involves design, procurement, implementation and testing across various disciplines such as mechanical, electrical, instrumentation and control engineering. The WRAM also has to be modelled such that it can be executed efficiently in real-time.
The outcomes of this work will feed directly into SGL’s development program for the WRAM. Additionally, the newly developed test rig has shown independent commercial potential for exploiting its functionality for a variety of applications.
Project Supervisor: Prof. Biswajit Basu