Dynamic Performance Enhancement of AquaBuOY Grid-Connected Wave Energy Conversion System Using Transient Search Optimization Algorithm

This paper proposes an optimal proportional-integral (PI) controller scheme to improve the dynamic performance of a grid-connected AquaBuOY wave energy conversion system (WECS). Existing wave energy converters (WECs) control studies often treat the generator-side converter (GSC), grid-side inverter (GSI), and grid-fault response separately; consequently, the coordinated tuning of generator-side and grid-side PI loops under symmetrical and unsymmetrical faults remains insufficiently investigated in an integrated AquaBuOY WECS model. To address this gap, a wave-to-grid AquaBuOY model comprising the heaving device, simplified Pelton turbine stage, permanent magnet synchronous generator (PMSG), GSC, DC link, GSI, transformer, and transmission line is formulated in the synchronous d-q frame. Twelve PI gains are optimized simultaneously using the Transient Search Optimizer (TSO) by minimizing a weighted integral squared error (ISE) objective. While the GSC maximizes power extraction and minimizes losses, the GSI regulates the DC link and point of common coupling voltages. The proposed tuning is benchmarked against Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) settings under identical bounds and disturbance scenarios. The TSO-tuned controller achieves the lowest ISE value of 0.19045, corresponding to 36.5% and 14.1% reductions compared with PSO and GA, respectively.