A Francis turbine includes a waterway, an impeller disposed in the waterway, a distributor apparatus disposed in the waterway and an additional element for adjusting the flow of water through the turbine. The additional element is disposed in the waterway upstream of the impeller in the water flow direction, and the additional element includes a perforated metal sheet that may be brought into the waterway. A method for operating such a turbine is also provided.

The present invention relates to a movable and semi-submerged power generator using a waterwheel turbine, which can easily be moved to a location where a flow of a fluid occurs, prevents movement by current of water due to being a semi-submerged type, and efficiently produces energy by means of a flow rate control and cutoff of the fluid and expansibility of the turbine. The power generator comprises: an upper structure having first and second structures including first and second balancing tanks and first and second machine rooms; a lower structure disposed on the lower portion of the upper structure and including a fluid flowing hole, a first round, and a fluid guide hole through which the fluid can flow; a turbine rotated by the movement of the fluid; an energy generation means for producing electricity by the turbine; and a fixing means. Thus, the power generator is floatable and movable on water so as to be moved to and installed in various locations. The first and second balancing tanks are filled with the fluid such that the power generator can be semi-submerged, and the height of the turbine is disposed at a position so that a shaft can be placed above the water surface such that the turbine is smoothly rotated, while preventing shaking by waving of the fluid and turning of the power generator, thereby improving energy production efficiency. Also, the fluid under the water surface is guided in a direction capable of operating the turbine while maximally preventing disruption to the flow of the fluid moving to the turbine through the first round of the lower structure, thereby improving energy production efficiency.

A system for extracting energy for landing gear retraction may comprise a wheel pump rotationally coupled to a wheel via a pinion gear. A landing gear control valve assembly may be fluidly coupled to an output of the wheel pump. A secondary pump may be fluidly coupled to the landing gear control valve assembly, and an electric motor may be operationally coupled to the secondary pump.

A system for extracting energy for landing gear retraction may comprise a wheel pump rotationally coupled to a wheel via a pinion gear. A landing gear control valve assembly may be fluidly coupled to an output of the wheel pump. A secondary pump may be fluidly coupled to the landing gear control valve assembly, and an electric motor may be operationally coupled to the secondary pump.

The invention provides a pumped storage system with waterfall control subsystem, architected to enable optimized achievement of two primary goals in the context of a geography with upper and lower water bodies such as lakes, which are connected by a river with a waterfall. The first primary goal comprises energy storage utilizing a pumped storage system between two water bodies of different elevation, which can store energy from excess power production periods and return that energy by producing power to fill needs during deficit power production periods. The second primary goal comprises touristic value & waterfall viewer satisfaction combined with environmental & ecological objectives. A multiobjective control subsystem is utilized for synthesis of time-domain control commands aimed towards optimized achievement of the aforesaid two primary goals, and for control of the pumped storage system with waterfall control subsystem responsive to these time-domain control commands.

The invention provides a pumped storage system with waterfall control subsystem, architected to enable optimized achievement of two primary goals in the context of a geography with upper and lower water bodies such as lakes, which are connected by a river with a waterfall. The first primary goal comprises energy storage utilizing a pumped storage system between two water bodies of different elevation, which can store energy from excess power production periods and return that energy by producing power to fill needs during deficit power production periods. The second primary goal comprises touristic value & waterfall viewer satisfaction combined with environmental & ecological objectives. A multiobjective control subsystem is utilized for synthesis of time-domain control commands aimed towards optimized achievement of the aforesaid two primary goals, and for control of the pumped storage system with waterfall control subsystem responsive to these time-domain control commands.

The present invention is a method of controlling a wave energy system (COM), wherein the force f.sub.ex exerted by the waves on a mobile float of the wave energy system is estimated, then at least one dominant frequency .sub.ex of the force exerted by the waves on the mobile float is determined using an unscented Kalman filter (UKF), and the control (COM) of the wave energy system is determined by a variable-gain PI control law whose coefficients are a function of dominant frequency .sub.ex.

The present invention is a method of controlling a wave energy system (COM), wherein the force f.sub.ex exerted by the waves on a mobile float of the wave energy system is estimated, then at least one dominant frequency .sub.ex of the force exerted by the waves on the mobile float is determined using an unscented Kalman filter (UKF), and the control (COM) of the wave energy system is determined by a variable-gain PI control law whose coefficients are a function of dominant frequency .sub.ex.

A hydroelectric generation device has a main channel, at least one branch channel, at least one storage unit, and at least one generator set. The at least one storage unit is mounted in the at least one branch channel, and each storage unit has a container. The at least one generator set is mounted respectively in the at least one storage unit, and each generator set has a generating tube, at least one connection pipe, and a generating unit. The generating tube is mounted in the container. The at least one connection pipe is connected with the generating tube and is bent into an inverted L shape. The generating unit has at least one blade wheel assembly mounted rotatably in the generating tube.

A hydroelectric generation device has a main channel, at least one branch channel, at least one storage unit, and at least one generator set. The at least one storage unit is mounted in the at least one branch channel, and each storage unit has a container. The at least one generator set is mounted respectively in the at least one storage unit, and each generator set has a generating tube, at least one connection pipe, and a generating unit. The generating tube is mounted in the container. The at least one connection pipe is connected with the generating tube and is bent into an inverted L shape. The generating unit has at least one blade wheel assembly mounted rotatably in the generating tube.