Flow power plant having pivoting blades
View Patent ↗A flow power plant comprises a rotor rotating about a rotation axis and having a plurality of pivoting blades. Each pivoting blade is mounted to the rotor for pivoting between a position pivoted-in towards and a position pivoted-out away from the rotation axis. One separate electric machine operable both as a motor and as a generator is assigned to each pivoting blade for applying torques between the rotor and the pivoting blade. A controller separately controls the separate electric machines during each revolution of the respective pivoting blade together with the rotor around the rotation axis in such a way that a predetermined course of a pivot angle of the respective pivoting blade results between the pivoted-in position and the pivoted-out position. The predetermined course of the pivot angle is predetermined for a maximum recovery of energy from a flow flowing against the rotor transversely to the rotation axis.
1. A flow power plant comprising
a rotor configured to rotate about a rotational axis;
a plurality of rotor blades, each of the plurality of rotor blades configured to rotate about a respective pitch axis parallel to the rotational axis between a first position where the rotor blade is pivoted toward the rotational axis and a second position where the rotor blade is pivoted away from the rotational axis;
a plurality of electric machines mounted to the rotor, each of the plurality of electric machines being operably connected to a respective one of the plurality of rotor blades and configured to apply or receive a torque about the respective pitch axis of the respective one of the plurality of rotor pivoting blades;
a controller configured to individually control a pitch angle of each of the plurality of rotor blades;
wherein each of the plurality of electric machines is operable as a motor and a generator; and
wherein the controller is configured to individually control each of the plurality of electric machines such that each of the plurality of rotor blades pivots along a respective determined trajectory from the first position to the second position, the respective determined trajectory being determined for each revolution of the rotor.
2. The flow power plant of claim 1 , wherein the controller is further configured to automatically optimize the respective determined trajectory.
3. The flow power plant of claim 2 , wherein the automatic optimization is configured to obtain a maximum power transfer from a flow impacting the rotor.
4. The flow power plant of claim 3 , wherein the maximum power transfer is determined based on:
a plurality of energy values transferred to the rotor during previous revolutions of the rotor,
a plurality of flow parameter values obtained during previous revolutions of the rotor, and
at least one prior determined trajectory obtained during at least one previous revolutions of the rotor.
5. The flow power plant of claim 1 , wherein the controller is further configured to:
begin pivoting a respective rotor blade of the plurality of rotor blades toward the second position prior to the respective rotor blade engaging with a flow of fluid, and
to control a pitch angle of the respective rotor blade such that it is not in the first position while the respective rotor blade remains engaged with the flow of fluid.
6. The flow power plant of claim 1 , wherein the controller is connected to a vibration sensor and configured to individually control the plurality of electric machines such that vibrations corresponding to a fundamental rotation frequency of the rotor and a harmonic rotational frequency of the rotor are reduced.
7. The flow power plant of claim 1 , wherein each of the plurality of electric machines comprises a linear motor.
8. The flow power plant of claim 1 , wherein an energy storage device is mounted to the rotor and configured to store electric energy generated by the plurality of electric machines when the plurality of electric machines are operated as generators.
9. The flow power plant of claim 8 , further comprising a main electric machine operably connected to the rotor and configured to receive a stored electric energy from the energy storage device, wherein the stored electric energy is used to operate the main electric machine as a motor to apply a torque to the rotor.
10. The flow power plant of claim 1 , wherein the controller is further configured to pivot each of the plurality of rotor blades from the second position to the first position such that the rotor is accelerate.
11. The flow power plant of claim 1 , further comprising a main electric machine operably connected to the rotor and configured to operate as a motor and a generator, the main electric machine being electrically connected to an electric load and/or an energy storage device.
12. The flow power plant of claim 11 , wherein the controller is further configured to measure an electric power output of the main electric machine when it is operated as a generator.
13. The flow power plant of claim 11 , wherein the controller is configured to control the main electric machine such that an angular velocity of the rotor is optimized.
14. The flow power plant of claim 11 , wherein the main electric machine is operated as a motor to drive the rotor.
15. The flow power plant of claim 1 , wherein the plurality of rotor blades comprises 3 to 6 rotor blades.
16. The flow power plant of claim 1 , wherein the rotor further comprises;
an inner cylinder arranged coaxially with the rotational axis;
a plurality of flow bodies arranged circumferentially about the inner cylinder and configured as fixed blades of the rotor;
wherein each of the plurality of flow bodies is provided with a front side facing into a direction of rotation of the rotor, a rear side facing against the direction of rotation, and a trailing edges positioned radially outward with respect to the rotational axis; and
wherein each of the respective pitch axes are arranged adjacent to a respective trailing edge of the plurality of flow bodies.
17. The flow power plant of claim 16 , wherein the plurality of rotor blades are arranged such that, in the first position, an openings remains between each of the plurality of rotor blades and the front sides of the plurality of flow bodies.
18. The flow power plant of claim 1 , further comprising
a second rotor configured to rotate about a second rotational axis;
a second plurality of rotor blades, each of the second plurality of rotor blades configured to rotate about a respective pitch axis parallel to the second rotational axis between a first position where the rotor blade is pivoted toward the second rotational axis and a second position where the rotor blade is pivoted away from the second rotational axis; and
a flow channel having a longitudinal center plane;
wherein the rotor and the second rotor are mirror-symmetrically arranged with respect to the longitudinal center plane of the flow channel and rotate in opposite directions about the rotating axis and the further rotational axis, respectively.
19. The flow power plant of claim 18 , wherein the flow channel is delimited by flow guiding elements.
20. The flow power plant of claim 18 , wherein:
the plurality of rotor blades is a first plurality of rotor blades; and
the flow channel is essentially blocked by pivoting-out the pivoting rotor blades of the first plurality of rotor blades and the second plurality of rotor blades into their respective second positions.