Abstract
Marine renewable energy technologies offer strong potential for clean, predictable, and locally sourced power generation, particularly for riverine, island, and remote communities. Despite sustained research progress, large-scale deployment remains limited due to challenges in mechanical efficiency, subsystem reliability, experimental readiness, and social acceptance. This dissertation addresses these challenges through a convergence-oriented framework that integrates physics-based modeling, experimental validation, control co-design, and stakeholder-informed decision-making to support community-scale marine energy deployment.
The dissertation begins with the dynamic modeling and experimental validation of a PTO mechanism for a bio-inspired oscillating hydrofoil-based hydrokinetic energy converter. Inspired by fish swimming dynamics, the system employs an MMR to convert oscillatory motion into unidirectional rotation. A ball screw–based MMR PTO is modeled and experimentally characterized through dry-laboratory testing on an Instron servo-hydraulic system and benchmarked against a rack-and-pinion configuration. Model predictions show strong agreement with experiments, capturing friction-dominated loss mechanisms. Results indicate that dry (Coulomb) friction governs low-speed behavior, while viscous losses increase with velocity. After accounting for alignment effects, the PTO achieves a peak mechanical efficiency of approximately 75% at an optimal electrical load, establishing a validated foundation for system-level design.
Building on this validated subsystem, the research advances to the design, scaling, and control co-design optimization of a 1 kW-class dual-hydrofoil hydrokinetic energy converter. A nonlinear time-domain model is developed using the Euler–Lagrange formulation, and a unified optimization framework simultaneously tunes hydrofoil kinematics, structural parameters, and generator torque control. Treating the oscillation period as an optimization variable enables realistic capture of system dynamics. At a representative flow velocity of 1.5 m/s, the optimized design produces approximately 1 kW of electrical power with an overall power train efficiency of 59%. Comparative studies demonstrate that neglecting actuator energy consumption leads to systematically overestimated performance, underscoring the necessity of control-aware design.
To bridge the gap between simulation and deployment, the dissertation introduces a CFD xvi informed HIL experimental framework for PTO validation. Unsteady hydrodynamic forces derived from computational fluid dynamics are emulated in real time using a Brushless Direct Current (BLDC) motor, while an AFPM extracts power under closed-loop PI control. Gain sweep experiments reveal strong sensitivity of power output to proportional control gains and highlight trade-offs between power maximization and mechanical safety constraints. Simulations and experiments predict mean generator power up to 0.5 kW, peak power approaching 1 kW, and PTO mechanical efficiency of approximately 69%, demonstrating experimental readiness for tow-tank and field testing.
Recognizing that technical performance alone is insufficient for successful deployment, the dissertation culminates in the development of BlueChoice, a community-centric decision support framework that integrates qualitative stakeholder input with quantitative engineering metrics. Using WHFS, the AHP, and TOPSIS ranking within a unified Multi-Criteria Decision Making (MCDM) framework, BlueChoice enables transparent and participatory selection of WEC technologies. Applied to a case study on Beaver Island, Michigan, the framework consistently identifies an oscillating wave surge converter as the preferred option over point absorber and oscillating water column alternatives, retaining the top rank in over 95% of Monte Carlo sensitivity runs. Collectively, this dissertation demonstrates a scalable pathway for converging marine energy research across disciplinary boundaries, linking vali dated device-scale innovation to community-scale impact and long-term social acceptance.