Modern multi-energy systems aim to incorporate emerging renewable energies to minimize resource variability and improve power provision. Among these, marine energy converters show great promise within integrated energy systems, due to the abundance of underutilized marine resources and their higher predictability compared to other renewable sources. Wave power, in particular, has emerged as a viable option due to its energy density and predictability. However, optimizing the energy extraction efficiency of wave energy converters is crucial to make them viable as generation modules. This requires specially designed control setups, capable of addressing this challenge. This chapter explores a hydrodynamic control approach from a tracking loop perspective, utilizing higher-order sliding mode control as a robust tracking algorithm. Experimental results demonstrate that the proposed control methods surpass traditional methods in extracting energy from waves, thereby enhancing the performance of wave energy converters and enabling their significant contribution to hybrid energy systems.