It is well known in the literature that the total absorbed energy of a farm of wave energy converter depends, within a wide range of variability, on the hydrodynamic interaction between the individual devices. Several studies have addressed the problem of controlling the wave energy converters so as to exploit the positive interaction between the devices in order to increase the total amount of absorbed energy. This paper studies two types of control systems for array of wave energy converters: the first is similar to the classical optimal control which uses the complete (linear) hydrodynamic model of the array and information about the status (velocity) of the other devices, while the second is a suboptimal control systems which calculates the optimal motion while neglecting completely the interaction between the devices. Most importantly the comparison is carried out considering the effects of constraints on the maximum allowed oscillation amplitude and PTO force