Dielectric elastomer wave energy harvester with self-bias voltage of an ancillary wind generator to power for intelligent buoys

•A novel dielectric elastomer ocean wave energy harvester with self-bias voltage is proposed.•Theoretical model of the integrated generation for wave and wind energy harvesting is developed.•The releasing and tensioning activity of dielectric elastomer were assessed on the ocean condition.•The boost voltage system connects the wind generator and the DE-film to replenish the bias voltage. The dielectric elastomer (DE) ocean wave energy harvester is a promising option of affordable and reliable power for the buoy’s intelligent wireless sensors. A novel DE energy converter system is proposed with self-bias voltage from the ancillary wind turbine generator. The operating principle of the combined power generation is introduced with the electromechanical coupling of DE-film and the power take-off of the oscillating water column (OWC) in the hollow buoy. In essence, the DE generator is a variable polymer dielectric capacitor, coated by compliant electrodes. The wind turbine generator as the supplemental electric energy provides the bias voltage on the DE-film to realize the conversion of elastic mechanical energy into electric energy. Furthermore, the developed theoretical model can describe the electricity generation performance of wave and wind energy harvesting, which is verified by the existing experiment. On this basis, it evaluates the air pressure in the OWC chamber and the output electric energy on the DE-film. The maximum electrical energy is about 1.4 J with the bias voltage of 1.0 kV and the deformation displacement of 120 mm on the top of the DE-film. To recharge the DE-film, an interface circuit is proposed to boost the low voltage of the wind energy generator up to the required bias voltage for the DE-film generator. The research results can provide effective solutions for the DE generator, especially the bias voltage approach, in the insights of ocean energy harvesting.