Harvesting ocean wave's kinetic energy is a promising way to supply electricity to the smart ocean network. Also, since the smart ocean network is distributed sparsely in the scale of hundreds of kilometers, supplying electricity onsite would be most efficient. It is well studied that the ocean is abundant in wave kinetic energy, however, the low frequency of the wave is often out of many traditional energy conversion devices’ optimal performance region. To tackle this issue, traditional wave capture devices are often of large scale, or semi-permanently anchored, which have almost no constraints on the size of the devices. Hence, the size of the traditional device is advantageous in the capture efficiency as the kinetic energy absorber can be much larger, and advanced energy storage schemes can be easily employed. Yet, mobility of the traditional devices may still be the limiting factor. To generate electricity onsite, small form factor wave energy capture devices must work with constrained size of the kinetic energy absorbed, and the energy storage means is very limited. As a result, small form factor wave capture device has to boost the frequency of capturable motion, to drive the electrical generation device in its most efficient region. In this paper, a direct-acting electromagnetic wave energy capture device is proposed, designed, and simulated, with key performance indicators optimized. The proposed device architecture is similar to a linear motor, but has the capability of boosting vibration frequency of the captured motion with the help of a designed fluid power transmission circuit to boost the capturable motion frequency. Initial design analysis has shown the device is capable of boosting the capturable motion frequency over the incident wave frequency by a factor of 10.
As an important part of the marine sensor data network, data buoys are widely used in ocean monitoring applications. Compared with the land-based counterparts, supplying electric power through transmission lines to the ocean deployed data buoy are usually impractical due to its far distance away from the centralized power generators on the mainland (Albaladejo, Sánchez, Iborra, Soto, López and Torres, 2010). The current sensor buoy power systems usually employ photovoltaic panels and batteries, yet their power output is becoming more of a threshold against the ever-increasing complexity of onboard metrology instruments, especially at long term service (Zhou and Yi, 2013). Moreover, when some battery equipped data buoys are lost or sunk in the ocean due to severe weather or poor maintenance, the environmental concerns of such devices may rise (Nolte, Ertekin and Davis, 2013).
