Efficient Motor Drives for Wave Energy Converters

Marine wave energy remains a promising and substantial resource with applications that span large scale grid connected systems, to small self-contained systems that harness the consistent nature of waves to power remote sensors, communication devices, etc. Nevertheless, many open challenges related to efficiently capturing energy in wave energy converters (WECs) remain. This work describes recent wave-tank testing of a point absorber WEC that utilizes a programmable power electronic motor drive to study the impact of drive characteristics on conversion efficiency. Regular periodic wave tests reveal several parameters which can have a large impact on drive efficiency (control gains, dc bus voltage, switching frequency, etc.) From these tests, optimal parameters were also determined and evaluated in realistic irregular wave conditions modeled using JONSWAP wave spectra. The findings of this work may be of value to WEC power train designers and may serve as reference for further research on efficient drives for wave energy applications.