Dynamic Stability Improvement of AWS-Based Wave Energy Systems Using a Multiobjective Salp Swarm Algorithm-Based Optimal Control Scheme

This article presents a novel attempt to fine-tune all proportional-integral (PI) controllers of all power electronic circuits based on the salp swarm algorithm (SSA) to enhance both dynamic and transient stability of grid-tied wave energy conversion systems (WECSs). The WECS is based on the Archimedes wave swing unit that is connected with a permanent magnet synchronous generator. It is connected to the grid through a generator side converter (GSC) and a grid-side inverter (GSI). The GSC is controlled to minimize the generator power loss and maximize its power output. The GSI is controlled to maintain the terminal voltage and dc-link voltage via a cascaded control approach. Optimal PI controllers by using the SSA are implemented in these converters. The integral square error criterion is selected as a multiobjective function. The validity of SSA-based-PI controllers is verified by comparing their results with that achieved by genetic algorithm-based-PI controllers at severe disturbance of the power grid. To achieve a realistic study, measured wave pressure data extracted from a Portugal wave power plant are implemented in the dynamic analyses. The effectiveness of SSA-based PI controllers is tested under uncertainty of the real wave pressure of such WECSs. The dynamic studies are extensively performed using PSCAD/EMTDC program.