A singular value decomposition-based velocity tracking control has been applied to the submerged multi-degree-of-freedom wave energy converter (WEC). This controller is causal, robust, and achieves the optimal amplitude and phase between the buoy velocity and the excitation force in both heave and surge modes. The analysis of the controller sensitivity has revealed that while the low-level control loop is robust, the high-level reference point generator requires a high-fidelity model of the WEC in or-der to satisfy the optimal phasing condition. The performance of the proposed controller has been compared with a quasi-standard spring-damper approach, where a 15% increase in power production is achieved for the deployment site considered.

multivariable control，power take-off，three-tether WEC， wave energy converter