Abstract: A multiple oscillating water pumping device includes: a wing member disposed in fluid to generate a lifting force using the flow energy of the fluid; a rotation device to reciprocally rotate the wing member to periodically change the direction of the lifting force acting on the wing member; an arm is rotatably coupled to the wing member, the arm being reciprocally rotated about a pivot shaft by the lifting force acting on the wing member; and a cylinder where fluid enters and exits according to the internal pressure that is periodically increased and decreased by the reciprocating motion of a piston that is connected with the arm through a connecting rod. The multiple oscillating water pumping device is configured to minimize the supply of a power source required for operation and to minimize the loss of head when pumped water flows toward a reservoir along a conduit.

Abstract: Disclosed is a diffuser controller for tidal stream power generation, for use in a tidal stream power generator installed under water to generate electricity using a tidal stream. The diffuser controller includes: a turbine configured to be rotated by the tidal stream; a diffuser which is formed with an inlet through which a fluid flows into the diffuser and an outlet through which the fluid flows out from the diffuser, the turbine being fixed inside the diffuser and a rear foil being rotatably installed in the outlet; and a control unit configured to adjust an rotating angle of the rear foil depending on a direction or velocity of the tidal stream. The diffuser is configured to be rotatable.