WE CLAIM:
1. A blade pitch system for a wind turbine, the wind turbine
comprising one or more blades, the blade pitch system comprising:
one or more motors configured to pitch the one or more blades of the wind turbine; and
a power source comprising:
a plurality of energy storage devices coupled in series, the plurality of energy storage devices configured to provide power to the one or more motors during a power loss event; and
at least one bypass current device configured to allow a bypass current to provide power from at least one energy storage device to the one or more motors;
wherein the bypass current comprises a current that bypasses one or more failed energy storage devices in the plurality of energy storage devices.
2. The blade pitch system as claimed in claim 1, wherein each energy storage device comprises either a battery or a supercapacitor.
3. The blade pitch system as claimed in claim 1, wherein the bypass current device comprises a power diode.
4. The blade pitch system as claimed in claim 1, comprising:
a control device configured to determine that an energy storage device has failed.
5. The blade pitch system as claimed in claim 4, wherein the control device is configured to determine that an energy storage device has failed based at least in part on a voltage across the at least one bypass current device.
6. The blade pitch system as claimed in claim 4, wherein the control device is further configured to provide an alert for scheduled maintenance to be performed on the failed energy storage device.
7. The blade pitch system as claimed in claim 4, wherein the bypass current device comprises a switching device;

wherein the switching device comprises a MOSFET or IGBT switching device; and
wherein the control device is further configured to control the switching device to allow the bypass current to bypass the failed energy storage device.
8. The blade pitch system as claimed in claim 1, wherein the at least one bypass current device is positioned in parallel with at least one energy storage device.
9. The blade pitch system as claimed in claim 1, comprising:
a fuse coupled between at least one energy storage device in the plurality of energy storage devices and the at least one bypass current device; wherein the bypass current flows through the fuse.
10. The blade pitch system as claimed in claim 9, wherein the fuse is configured to protect against a short circuit in the bypass current device or an incorrectly installed bypass current device.
11. The blade pitch system as claimed in claim 1, wherein the at least one bypass current device comprises a plurality of bypass current devices; and
wherein a bypass current device is coupled in parallel with each energy storage device.
12. The blade pitch system as claimed in claim 11, comprising:
a plurality of fuses;
wherein each fuse is coupled between at least one energy storage device and at least one bypass current device coupled in parallel with the at least one energy storage device.
13. A method for providing power to one or more motors of a blade
pitch system to pitch one or more blades of a wind turbine, the method
comprising:
determining, by a control device, that a power loss event has occurred;
causing, by the control device, a power source to be electrically coupled to the one or more motors, the power source comprising a plurality of energy storage devices coupled in series and at least one bypass current device coupled in parallel with at least one energy storage device;

determining, by the control device, that an energy storage device has failed; and
controlling, by the control device, the bypass current device to allow a bypass current to bypass the failed energy storage device to provide power to the one or more motors.
14. The method as claimed in claim 13, wherein the bypass current
device comprises a MOSFET or IGBT switching device; and
wherein controlling, by the control device, the bypass current device to allow a bypass current to bypass the failed energy storage device to provide power to the one or more motors comprises controlling the MOSFET or IGBT switching device to allow the bypass current to bypass the failed energy storage device.
15. The method as claimed in claim 13, wherein determining, by a control device, that a power loss event has occurred comprises detecting, by the control device, a voltage or current anomaly of an electrical grid.
16. The method as claimed in claim 13, wherein determining, by the control device, that an energy storage device has failed comprises determining, by the control device, that an energy storage device has failed based at least in part on a voltage across the at least one bypass current device.
17. The method as claimed in claim 13, comprising:
providing an alert for scheduled maintenance to be performed on the failed energy storage device.
18. A wind turbine system, comprising:
a wind turbine comprising one or more blades; and a blade pitch system, comprising:
one or more motors configured to pitch the one or more blades; and
a power source comprising:
a plurality of energy storage devices coupled in series, the
plurality of energy storage devices configured to provide power to
the one or more motors during a power loss event; and

at least one bypass current device configured to allow a bypass current to provide power from at least one energy storage device to the one or more motors;
wherein the bypass current comprises a current that bypasses one or more failed energy storage devices in the plurality of energy storage devices; and
wherein the at least one bypass current device comprises at least one diode, MOSFET switching device, or IGBT switching device.
19. The wind turbine system as claimed in claim 18, comprising:
a fuse coupled between at least one energy storage device in the plurality of energy storage devices and the at least one bypass current device; wherein the bypass current flows through the fuse.
20. The wind turbine system as claimed in claim 18, comprising:
a control device configured to determine that an energy storage device has failed.