Current power generator using an oscillating hydroplane

A conceptual design of a current power generator which uses an oscillating hydroplane is examined; which can be applied to the relatively low current speed. The proposed current power generator has 2 degrees of freedom, sway and yaw. It uses oscillatory sway motion of the hydroplane to obtain electricity from the current flow. The sway motion is induced by the lift force due to the sinusoidal yaw motion of the hydroplane driven by an actuator. In order to assess the performance of the proposed current power generator, a mathematical model was developed considering quasi-steady lift and moment, added mass and wake effect of the oscillating hydroplane. In the mathematical model, the generator was modeled as a linear damper and the optimal power of the current power generator was found by varying the damping coefficient of the generator. The mathematical model was validated through a series of experiments was performed at 2-D tank with the laboratory scale model. During the experiments, the yaw motion of the hydroplane was controlled to follow the pre-determined sinusoidal motion with given amplitude and frequency by an electric motor. A virtual damper was designed using another electric motor producing damping torque proportional to the sway velocity. In this model, the dissipated power by the damping torque of motor is assumed to be equivalent to the generated power of the generator. The damping torque from the generator model was varied to obtain the optimal power by the hydroplane. Angle, angular velocity and torque of the each motor were measured; from the measurements harness power from the current flow and consumed power to actuate the hydroplane were calculated. Both simulation and experimental results showed good agreements; the developed mathematical model can be used for the further design.