A Fault-Tolerance MPPT Design and Model Analysis for Hydrokinetic Turbine Systems

This work proposes a converter-generator fault-tolerance strategy for a fixed-pitch hydrokinetic turbine (HKT) with a converter 4
^th
leg connected to the generator neutral point. A maximum power point tracking (MPPT) control for post-fault operation is also investigated. A PLECS model is used to verify the fault-tolerance strategy's practicality, and the controller is verified with hardware-in-the-loop (HIL) on fault transition and post-fault steady-state operations. The MPPT power control combined with the fault-tolerance strategy can maximize the HKT operating range under various conditions. The HKT system is also simulated on a MATLAB multi-physics model over a one-year water mission profile. Then a case study is made to look into the impact of the fault-tolerance strategy on the system's reliability and cost-effectiveness. The case study shows that the fault-tolerant system has a 14.51% energy generation increase compared with a non-fault-tolerant system.