TOLWEC: Fault diagnosis and fault-tolerant control for reliable wave energy converters

The EU aims to raise the European share of renewables from 23% in 2023 to 42.5% by 2030. Such a goal implies obtaining clean energy from diverse sources.

Although sea waves can provide a massive contribution in this sense, the commercial use and development of wave energy converters (WECs) are still very limited.

This fact has been attributed to expensive production, installation, and maintenance, caused by the hostility of the sea environment and the corrosive nature of seawater.

To achieve an appropriate balance between reliable performance and economic costs of WECs, the main objective of the TOLWEC project is to build a framework for fault diagnosis (FD) and fault-tolerant control (FTC) based on a multilevel scheme, composed of local fault handling (i.e., FD and FTC) of each subsystem of the WEC, coordinated by a higher-level fault handling for the whole WEC.

The main subsystems of a WEC are (i) a primary converter (PC) that captures mechanical energy from the waves, (ii) a power take-off (PTO) that converts mechanical energy into “raw” electric energy, and (iii) an electric power converter (EPC) that makes electric energy fit for consumption. Each subsystem has sensors and actuators for the diagnosis and control tasks.

The sensors measure dynamic variables of the system, while the actuators allow one to shape the behavior of the system.The proposed research requires obtaining high-fidelity models of each subsystem, modelling possible faults, assessing the availability and cost of sensors and actuators, and designing the local and global FD and FTC schemes.As a result, the proposal will increase the economic viability of WECs by (i) reducing operational costs with accurate and early FD to avoid expensive repairs, (ii) preserving the energy conversion in the presence of faults with a multilevel FTC scheme, and (iii) avoiding a substantial increase of the installation cost by establishing the priority of redundant sensors and actuators in the system.