A fluid-electromechanical co-simulation model for vertical-axis hydrokinetic turbines and its experimental validation

A fluid-electromechanical co-simulation model for vertical-axis hydrokinetic turbine (VAHT) is proposed and experimentally validated. This model dynamically couples hydrodynamic simulations in STAR-CCM+ with electromechanical system modeling in AMESim, enabling integrated analysis of the complete energy conversion process—from hydrodynamic energy capture to electrical power output. To meet the cost and reliability requirements of small-scale off-grid applications, an optimal torque control (OTC) strategy is employed and validated by the data measured in the circulating water channel test. Benefiting from the experimentally identified OTC method, maximum power point tracking (MPPT) can be implemented without the requirement for flow-velocity measurements. The fluid-electromechanical co-simulation results show close agreement between the predicted and measured power curves across flow velocities ranging from 0.2 to 0.8 m/s. Furthermore, the VAHT power generation system demonstrates stable operation and accurate MPPT performance under both linearly increasing (0.3-0.7 m/s) and step-varying flow conditions, highlighting its robust dynamic response and operational stability. The proposed approach provides both an effective simulation framework and a practical control solution for designing and optimizing low-cost, high-reliability vertical-axis tidal energy systems.