A New Active Motion Control Strategy for Built-in Wave Energy Converter of Ocean Data Buoys

The built-in direct-drive wave energy converter (WEC) can be installed in the ocean data buoy cabin to achieve efficient self-power supply. In the traditional uncontrolled state, its high-weight core power generation unit (CPGU) is prone to collision with the protection spring, causing the thrust of the CPGU to be greater than the maximum magnetic thrust of the magnetic lead screw (MLS), resulting in a magnetic slip phenomenon, which hinders the improvement of the built-in WEC power generation capacity. This article proposes a new active motion control strategy for the built-in direct-drive WEC. This control strategy controls the movement speed of the CPGU by adjusting the load damping to eliminate the collision between the high-weight CPGU and the spring. Therefore, the power generation capacity of the built-in direct-drive WEC can be improved by increasing the operable weight of the CPGU on the original MLS. The built-in direct-drive WEC prototype was fabricated in the laboratory and experimentally verified on a six-degree-of-freedom (6-DOF) platform. Experimental data show that under the active motion control strategy, the operable weight of the CPGU increases up to 90 kg, and the average power generation of the system reaches 7.28 W.