Abstract
Oscillating water columns (OWCs) are a type of wave energy converters that harness energy from the wave's oscillation inside a chamber caused by the wave's movement. This paper proposes a modified maximum power point tracking (MPPT) scheme for an OWC model to secure the operational stability of the turbine in the OWC and thereby maximizing the wave power extraction. Compared with the conventional MPPT control, the proposed MPPT control scales down the MPPT control gain used in the typical MPPT curve to avoid the stalling behavior of the turbine occurred beyond the optimal flow coefficient on the curve; thus, the proposed scheme can significantly improve the stability of an OWC system by tracking a suboptimal MPPT curve. The simulation results from PSCAD/EMTDC indicate the proposed scheme can secure stable operation of the OWC without causing stalling behaviors of the turbine.