Fluid power circuit having switch-mode power transformer and methods
A fluid power circuit with a switch-mode power transformer used to transfer power while keeping the pressure of power source and reverse osmosis processes relatively decoupled. The switch-mode power transformer uses the inertia of a hydraulic motor driven electric generator and switching of a hydraulic motor inlet between high and low-pressure ends to decrease the pressure at which power is being transmitted to a reverse osmosis process.
1. A fluid power circuit comprising:
a hydraulic power source having a high-pressure end and a low-pressure end;
a switch-mode transformer having a pumping mode and a motoring mode; the switch-mode power transformer including:
valving that connects a hydraulic inertial element to the high-pressure and low-pressure end of the hydraulic power source, and
the hydraulic inertial element having an outlet to a load and an electric generator having a rotor; and
a reverse osmosis system;
wherein when the valving is open to the high-pressure source and closed to the low-pressure source, the hydraulic inertial element is fluidly connected to the high-pressure end and the hydraulic inertial element operates as a motor;
wherein when the valving is closed to the high-pressure source and open to the low-pressure source, the hydraulic inertial element is fluidly connected to the low-pressure end and the hydraulic inertial element operates as a pump;
further wherein the generator is configured to convert excess mechanical power to electrical power, maintaining a mean fluid flow rate supplied to the reverse osmosis system.
2. The fluid power circuit of claim 1 , wherein the valving includes a switching valve and a check valve.
3. The fluid power circuit of claim 1 , wherein the hydraulic inertial element is a hydraulic pump/motor.
4. The fluid power circuit of claim 1 , wherein the hydraulic power source is part of a wave energy converter.
5. The fluid power circuit of claim 1 , wherein the hydraulic inertial element is fluid in a pipe.
6. The fluid power circuit of claim 1 , comprising a charge pump.
7. The fluid power circuit of claim 1 , comprising an accumulator.
8. A wave-powered reverse osmosis desalination plant comprising:
a wave energy converter including a hydraulic power source having a high-pressure end and a low-pressure end;
a switch-mode power transformer having a pumping mode and a motoring mode; the switch-mode power transformer including:
valving that connects a hydraulic inertial element to the high-pressure and low-pressure end of the hydraulic power source, and
the hydraulic inertial element having an outlet to a load and an electric generator having a rotor; and
a reverse osmosis system;
wherein when the valving is open to the high-pressure source and closed to the low-pressure source, the hydraulic inertial element is fluidly connected to the high-pressure end and the hydraulic inertial element operates as a motor;
wherein when the valving is closed to the high-pressure source and open to the low-pressure source, the hydraulic inertial element is fluidly connected to the low-pressure end and the hydraulic inertial element operates as a pump;
further wherein the generator is configured to convert excess mechanical power to electrical power, maintaining a mean fluid flow rate supplied to the reverse osmosis system.
9. The plant of claim 8 , wherein the valving includes a check valve and a switching valve.
10. The plant of claim 8 , wherein the hydraulic inertial element is a hydraulic pump/motor.
11. The plant of claim 8 , wherein the hydraulic power source is part of a wave energy converter.
12. The plant of claim 8 , wherein the hydraulic inertial element is a long, small-diameter pipe.
13. The plant of claim 8 , comprising a charge pump.
14. The plant of claim 8 , comprising an accumulator.
15. A method of producing power, the method comprising:
providing a wave-powered reverse osmosis desalination plant including:
a wave energy converter including a hydraulic power source having a high-pressure end and a low-pressure end,
a switch-mode power transformer having a pumping mode and a motoring mode, the switch-mode power transformer including:
valving that connects a hydraulic inertial element to the high-pressure and low-pressure end of the hydraulic power source, and
the hydraulic inertial element having an outlet to a load and an electric generator having a rotor; and
a reverse osmosis system.
16. The method of claim 15 , comprising opening the valving so that the hydraulic inertial element is fluidly connected to the high-pressure end and the hydraulic inertial element operates as a motor.
17. The method of claim 16 , wherein, when the valving is opened, a rotor of the hydraulic inertial element rotates.
18. The method of claim 16 , wherein the generator converts excess mechanical power generated by the rotor to electrical power, thereby maintaining a mean fluid flow rate supplied to the reverse osmosis system.
19. The method of claim 15 , wherein the hydraulic inertial element is a hydraulic pump/motor.
20. The method of claim 15 , comprising closing the valving so that the hydraulic inertial element is fluidly connected to the low-pressure end and the hydraulic inertial element operates as a pump.