Time-delay closed-loop control of an infinitely variable transmission system for tidal current energy converters

A tidal current energy converter (TCEC) comprising:

• (i) at least one infinitely variable transmission (IVT) comprising an IVT control system comprising a crank length controller, a forward speed controller, or both;
• and (ii) at least one vertical axis water turbine (VAWT), wherein the VAWT is a hybrid VAWT comprising:
• (a) a first rotor system positioned in a central region and rotatable about a central axis, wherein the first rotor system comprises:
• a plurality of first blades, each having a concave shape that allows fluid to push on a concave side of each first blade;
• and a hydraulic brake system that is mounted upon a shaft with bearings;
• and
• (b) a second rotor system positioned in an annular region surrounding the first rotor system in the central region, wherein the second rotor system comprises a plurality of second blades spaced about the central axis, wherein the cross-section of each second blade is a substantially symmetrical airfoil shape.

A tidal current energy converter (TCEC) comprising:

• (i) at least one infinitely variable transmission (IVT) comprising an IVT control system comprising a crank length controller, a forward speed controller, or both;
• and (ii) at least one vertical axis water turbine (VAWT), wherein the VAWT is a hybrid VAWT comprising:
• (a) a first rotor system positioned in a central region and rotatable about a central axis, wherein the first rotor system comprises:
• (i) at least two blade-sets stacked vertically along the central axis, each blade-set comprising a plurality of first blades that are spaced about the central axis, wherein the at least two blade-sets are mounted upon a shaft with bearings along the central axis, wherein each first blade extends from a position proximate to the central axis out to a position distal to the central axis and has a concave shape that allows fluid to push on a concave side of each first blade, and
• (ii) a hydraulic brake system that is mounted upon the shaft with bearings;
• and
• (b) a second rotor system positioned in an annular region surrounding the first rotor system in the central region, wherein the second rotor system comprises a plurality of second blades spaced about the central axis, wherein each of the second blades is positioned substantially parallel to the central axis and attached to at least one blade-set of the first rotor system using at least two supporting struts, wherein the cross-section of the second blade is a substantially symmetrical airfoil shape.