Autonomously operated buoys with power generation and power usage control

• US 20120248865A1
• Filed: 03/28/2011
• Published: 10/04/2012
• Est. Priority Date: 03/28/2011
• Status: Active Grant

• Current Assignee: Ocean Power Technologies, Inc.
• Original Assignee: Ocean Power Technologies, Inc.
• Inventors: Eder, James E., Sarokhan, Joseph A.
• Granted Patent: US 8,723,355 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: F03B 13/16 using the relative movement between a wave-operated member, i.e. a "wom" and another member, i.e. a reaction member or "rem"
• CPC Class Codes: F05B 2260/42 Storage of energy
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

Apparatus, intended to be deployed in a body of water, includes a payload comprised of a multiplicity of different electronic and electromechanical loads and a wave energy converter (WEC) system responsive to the amplitude of waves in the body of water for producing electrical power, which is a function of the wave amplitudes, to power the payload. The apparatus includes switching circuitry for controlling the application of power to selected ones of the loads. Control circuitry and devices which are responsive to the electric power being produced control the switching circuitry for controlling the amount of power supplied to, and consumed by, the loads.

Claims

1. Apparatus, intended to be deployed in a body of water, including:

(a) a payload comprised of a multiplicity of different electronic and electromechanical loads and (b) a wave energy converter (WEC) system responsive to the amplitude of waves in said body of water for producing electrical power at an output power port for powering the payload, said apparatus comprising;

switch means coupled between the output power port and selected ones of the different loads; and

control means responsive to the electric power being produced for controlling the switch means and the amount of power supplied to, and consumed by, the loads.

2. An apparatus as claimed in claim 1, wherein said control means includes a controller, responsive to the electric power being produced, which is programmed to control the switch means to reduce the power dissipated by selected loads when the power being produced is below a predetermined level.

3. An apparatus as claimed in claim 1, wherein said WEC system includes first and second bodies which move relative to each other in response to the waves and a power take off device (PTO) coupled between the first and second bodies for generating said electric power at said output power port and wherein the amount of power produced at the output port is a function of the amplitude of the waves.

4. An apparatus as claimed in claim 3, wherein said control means includes a controller programmed to control the turn on and turn off of the switch means to reduce the power dissipated by selected loads when the power being produced is below a predetermined level and wherein the controller also includes means for inhibiting movement between the first and second bodies when the amplitude of the waves exceeds a predetermined level.

5. An apparatus as claimed in claim 3, wherein said control means includes means for inhibiting the relative motion between the first and second bodies for at least one of the following conditions:

(a) when the amplitudes of the waves are below a predetermined level so that the relative movement between the two bodies would cause more power dissipation than can be generated; and

(b) when the amplitude of the waves exceeds a predetermined level threatening the destruction of the WEC; and

(c) to lock-up the WEC in order to minimize the emission of noise signals.

6. An apparatus as claimed in claim 3, wherein said control means includes means for selectively operating the WEC system in any one of the following states:

(a) a power generating state when the waves have an amplitude above a first value and below a second value;

where for said first value the WEC system generates sufficient power to overcome a minimum value of power dissipation which the WEC tends to dissipate and said second value is a predetermined level which if exceeded threatens the destruction of the apparatus;

(b) a sleep state in which very little power is consumed by the operating system whereby power drainage is limited to selected critical loads;

(c) a transitory wake-up state; and

(d) a lock up state in which there is no relative motion between the first and second bodies.

7. An apparatus as claimed in claim 3, wherein said control means includes at least one of:

(a) sensing means for directly sensing the amplitude of the waves impinging on the apparatus and producing sensing signals indicative thereof;

(b) sensing means for indirectly sensing the amplitude of the waves impinging on the apparatus and producing sensing signals indicative thereof;

(c) sensing means for sensing the output power available at the output port and producing sensing signals indicative thereof;

(d) sensing the voltage level at the output port and producing sensing signals indicative thereof; and

means responsive to the sensing signals for processing the sensing signals and controlling the switch means.

8. An apparatus as claimed in claim 3, wherein said apparatus includes a battery system connected to said output port and wherein said loads coupled via said switch means to said output port include at least one of a radar system, a camera system, a sonar system, a brake control system, and a communication system.

9. Apparatus intended to be deployed in a body of water in which waves of varying amplitude are produced and wherein said apparatus includes a wave energy converter (WEC) system for producing an amount of electric power at an output port which is a function of the amplitude of the waves, said electric power for powering a payload located on or about the apparatus, where the payload includes a multiplicity of different electronic, electrical and electro mechanical devices, said apparatus comprising:

switch means coupled between the output port and selected ones of the electronic, electrical and electro mechanical devices; and

control means responsive to the output power being produced for controlling the switch means and the amount of power supplied to, and consumed, by the loads.

10. An apparatus as claimed in claim 9, including energy storage means for storing the energy produced by said WEC system and said control means responsive to the output power being produced for controlling the switch means and the amount of power supplied to, and consumed, by the loads for reducing the power consumed by selected ones of the of the electronic, electrical and electro mechanical devices when the electric power being produced is below a predetermined level and for reducing the usage of the stored energy.

11. An apparatus as claimed in claim 9, wherein said WEC system includes:

a) first and second bodies which move relative to each other in response to the waves;

and b) a power take off device coupled between the first and second bodies for generating electric power at an output port and the amount of power produced at the output port is a function of the relative motion between the first and second bodies which in turn is a function of the amplitude of the waves.

12. An apparatus as claimed in claim 11, wherein one of the electro mechanical devices is a brake system coupled between the first and second bodies for selectively inhibiting motion between these two bodies.

13. An apparatus as claimed in claim 12, wherein said control means includes a controller for activating the brake system and inhibiting motion between the first and second bodies when:

(a) the amplitudes of the waves is below a predetermined level;

(b) the amplitude of the waves exceeds a predetermined level threatening the destruction of the WEC; and

(c) it is desired to reduce the emission of noise signals by the WEC.

14. An apparatus as claimed in claim 9, wherein there is included energy storage means coupled to the output port, and wherein said control means includes at least one of:

(a) sensing means for directly sensing the amplitude of the waves impinging on the apparatus and producing sensed signals indicative thereof;

(b) sensing means for indirectly sensing the amplitude of the waves impinging on the apparatus and producing sensed signals indicative thereof;

(c) sensing means for sensing the output power available at the output port and producing sensed signals indicative thereof; and

(d) sensing means for sensing the level of stored energy and producing sensed signals indicative thereof; and

wherein said control means includes a controller for processing the sensed signals and generating signals controlling the turn-on and turn-off of the switch means.

15. An apparatus as claimed in claim 14, wherein the electronic, electrical and electro mechanical devices include at least one of a camera system, a radar system, a sonar system, a brake control system, a communications systems, a radiation detector.

16. An apparatus as claimed in claim 14, wherein said control means includes a processor for processing the sensing signals with the processor being programmed to be responsive to the sensed signals to control the switch means to operate the renewable operating system and the loads in different operating modes as a function of the amplitude of the waves.

17. An apparatus as claimed in claim 14, wherein the WEC system is operated in any one of the following modes:

(a) a standard power generating mode when the amplitude of the waves and the corresponding power being produced is above a first value and below a second value;

(b) a lock-up mode in which the first and second bodies of the WEC system are inhibited from moving with respect to each other;

(c) a sleep mode in which very little power is consumed and the WEC is also in the lock-up mode; and

(d) a wake up mode which is an intermediate condition to determine whether to keep the system in the sleep mode or switch the WEC system to a standard power generating mode.

18. Apparatus, intended to be deployed in a body of water subjected to waves of varying amplitude, including:

(a) a payload comprised of a multiplicity of different electronic and electromechanical loads and (b) a wave energy converter (WEC) system responsive to the amplitude of the waves in said body of water for producing electrical power at an output port for powering the payload, said apparatus comprising;

power storage means coupled to said output port for storing produced electrical power;

switch means coupled between the output power port and selected ones of the different loads; and

control means responsive to the electric power being produced for controlling the switch means and the amount of power supplied to, and consumed by, the loads for modifying the payload'"'"'s power requirements to match the system'"'"'s energy capture in order to extend the power stored in said power storage means and the operability of the payload under adverse wave conditions.

19. Apparatus as claimed in claim 18 wherein said WEC system can operate autonomously;

optimizing its settings to the wave climate and manage its available energy reserves.

20. Apparatus as claimed in claim 18 wherein said switch means are controlled to r selectively connect and disconnect selected loads from the WEC'"'"'s power port for operating the system in different operational modes to manage power consumption as a function of selected climatic conditions and selected external conditions.

21. Apparatus as claimed in claim 18 wherein one of said loads is an on-board satellite radio to allow the apparatus to communicate with a remote command center so the operational status of the WEC system can be ascertained and, if necessary, it'"'"'s autonomous operating parameters over-ridden.

22. Apparatus as claimed in claim 21 wherein the on-board radio also allows for communication between the sensors and responders and the command center;

for controlling the payload as well as receiving telemetry data.

23. Apparatus as claimed in claim 18 wherein said WEC system includes first and second bodies which move relative to each other in response to the waves and a power-take-off device (PTO) coupled between the float and spar to convert their relative motion into electrical energy;

and wherein said payload includes a brake system to selectively inhibit the relative motion between the first and second bodies.

24. Apparatus as claimed in claim 23 wherein the brake system is activated under one of the following conditions:

(a) minimize the system'"'"'s overhead electrical draw for periods where low wave activity do not justify full operation of all of the WEC'"'"'s sub-systems;

(b) eliminate acoustic noise which may interfere with a selected sensor'"'"'s operation;

(c) lock the float and spar under storm conditions.

25. Apparatus as claimed in claim 24, wherein the brake system is activated in response to signals generated by selected sensors in response to wave conditions.

26. Apparatus as claimed in claim 25 wherein said power storage means includes batteries arranged in a redundant topology so that the failure of one battery in the array does not compromise the system'"'"'s ability to deliver power to the payload.

27. Apparatus as claimed in claim 25 wherein said first body a spar and the second body is a float;

and wherein said spar has a heave plate connected to a submerged portion of the spar; and

wherein said power storage means includes batteries arranged about said heave plate to increase its mass.

28. Apparatus as claimed in claim 18 wherein the control means includes an on-board controller including a program which embeds all control algorithms necessary for autonomous operation, control of the payload and communication with a command center;

and wherein the control means includes means for adjusting the payload'"'"'s duty cycle for power delivery to less than 100%.

29. Apparatus as claimed in claim 18 wherein said control means include sea state sensors to monitor the wave climate which along with a control algorithm, allow the WEC system to autonomously determine an optimum configuration of the WEC system to maximize the net energy extracted from the waves.

30. Apparatus as claimed in claim 29 wherein the sea state sensors may be one of the following:

a) a force sensor disposed between a braking device and one or more of the WEC'"'"'s moving bodies (e.g., float and spar) to monitor the force communicated from wave action through the brake;

or

b) a displacement sensor disposed between two or more of the WEC'"'"'s moving bodies (e.g., float and spar) to monitor their relative motion;

or

c) an accelerometer mounted on one or more of the WEC'"'"'s floating moving bodies to determine the motions induced on the body by wave action;

or

d) A method of monitoring the back EMF voltage of the generator without active control to determine the level of wave activity;

or

e) Other conventional wave sensors deployed in the vicinity of the system; and

wherein data from these sensors are processed to control the switch means.