Multiphysics and Multitimescale Modeling of Hydrokinetic Turbine Energy Conversion System

Hydrokinetic turbines (HKTs) show promise as a renewable energy source, but high maintenance costs and low energy output hinder their widespread adoption. Limited literature investigates HKT electric drivetrain designs, resulting in a knowledge gap toward increasing generation efficiency and lowering cost. Multiphysics (MLP) and multitimescale (MLT) modeling of HKT energy conversion systems focusing on power converters is an essential tool to be developed. This article first presents an integrated HKT energy conversion system using a MATLAB average model that incorporates electrical, mechanical, and thermal domains, as well as aging behaviors across different time frames, such as fixed-point and mission profiles. A power electronics switching-enabled PLECS model is then introduced, including maximum power point tracking (MPPT) control for the HKT, d–q reference framed modeling for the ac-dc–ac power converters, and a dynamic thermal framework, all together to predict fast transients and accurately maintain system stability. The developed models facilitate component-level optimization and improve the integrated performance of the system. Average and dynamic MLP models are validated through hardware experiments, hardware-in-the-loop (HIL) testing, and various simulations.