Development of a laboratory test bench for the emulation of wave energy converters

The design of a wave energy converter (WEC) requires the preliminary selection of dimensional parameters in accordance with variables such as location site, power take off (PTO) characteristics or control strategy, with the aim of developing a realistic model to be used in the test of power takeoff devices. The paper proposes a laboratory test bench to test direct-drive linear generators, for being integrated into a wave energy converter. In particular a point absorber type called IPS buoy is studied. The research is focussed in the methodology to get the model for an actuator which reproduces the behaviour that the wave converter would have in the real sea location. In order to get his model, a preliminary design procedure has been accomplished by means of an optimization problem solved using an Evolutionary Differential (DE) algorithm. Although a particular case study is faced, the method is independent of the type of direct drive and type of WEC, since restrictions, models and parameters can be adjusted accordingly. A reduced scale linear generator using permanent magnet tubular machines is developed driven by their power electronics each. One operated as an actuator and the other as a generator, but considering a common control strategy since the actuator depends on the generator respond. This test bench permits to accomplish several objectives such as estimating extracted power under different power extraction control or evaluating the force profiles and the mechanical behavior of the PTO, as well as testing different control strategies.