Development and Wave Tank Demonstration of a Fully Controlled Permanent Magnet Drive for a Heaving Wave Energy Converter

One option for converting the energy in sea waves into renewable electricity is the development of floating wave energy converters coupled to electrical generators. For this to work, bespoke slow-speed electrical machines coupled to bidirectional power smoothing power electronic converters are required. This paper reports on the successful design and wave tank validation of an electric machine, power converter and fully controlled direct drive power take-off system coupled to two small scale heaving wave energy converters. The design, development and demonstration of linear generators and power converters is presented including some simulated and laboratory results. Demonstration of wave energy converters with pure electric drives, fully automated control, bidirectional power flow and active force management is almost unique and essential for future wave energy development. The results presented prove that direct-drive power take-off for wave energy devices is technically possible and can be used to implement an automated control system with bidirectional power flow in both resonant and non-resonant wave energy systems.