System and method for protection of a wind turbine battery backup pitch control system

Patent metadata

Field	Value
Publication number	US-9726145-B2
Application number	US-201414470968-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Dec 31, 2013
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A pitch control system for a wind turbine includes a backup battery bank assigned to each pitch drive motor, with each battery bank having a plurality of individual batteries connected in series. A battery charger is connected in parallel across each battery in the battery bank. A protective circuit is configured with each battery charger and includes a voltage comparator circuit that detects a reverse voltage applied to the battery charger above a threshold value to isolate the battery charger from the reverse voltage.

First claim

What is claimed is:

1. A pitch control system for a wind turbine, wherein the wind turbine has one or more rotor blades coupled to a hub and a pitch drive motor assigned to each of the rotor blades, the system comprising;
a backup battery bank assigned to each pitch drive motor, each battery bank having a plurality of individual batteries connected in series;
a battery charger connected in parallel across each battery in the battery bank;
a protective circuit configured with each battery charger, the protective circuit comprising a voltage comparator circuit that detects a reverse voltage applied to the battery charger above a threshold value to isolate the battery charger from the reverse voltage, the protective circuit further comprising a surge suppressor connected in parallel between the battery charger and battery to suppress line voltage spikes from a transient open battery state during operation of the pitch control system,
wherein the sue suppressor comprises a varistor connected in parallel to a capacitor.

2. The pitch control system of claim 1 , wherein the protective circuit further comprises a switch device that is activated to isolate the battery charger upon detection of the reverse voltage above the threshold value.

3. The pitch control system of claim 2 , further comprising a battery charger controller configured to control the threshold value and switching hysteresis of the switch device.

4. The pitch control system of claim 1 , wherein the varistor comprises a MOV (metal-oxide varistor).

5. The pitch control system of claim 1 , further comprising a central controller and a communication link between the central controller and each of the battery chargers, wherein activation of the protective circuits is reported to the central controller via the communication link.

6. The pitch control system of claim 5 , wherein the central controller is a wind turbine controller.

7. The pitch control system of claim 5 , wherein the central controller is a site controller common to a plurality of wind turbines.

8. The system as in claim 2 , wherein, when the switching device is activated to isolate the battery charger from the battery, the surge suppressor protects the voltage comparator circuit from leakage inductance from the pitch drive motor.

9. A method for controlling a backup pitch control system of a wind turbine, comprising:
for each pitch drive in the pitch control system, configuring a plurality of batteries in series;
configuring a charging circuit with each of the individual batteries;
in the event of loss of line power or an emergency shutdown of the wind turbine, connecting the batteries to the pitch drive;
at each charging circuit, monitoring for a reverse voltage condition from a failure of the associated battery;
upon detection of a reverse voltage above a threshold value, disconnecting the charging circuit from the battery;
protecting the charging circuit from transient line voltage surges with a surge suppressor connected in parallel between the battery and the charging circuit,
wherein the surge suppressor comprises a varistor connected in parallel to a capacitor.

10. The method as in claim 9 , comprising monitoring for the reverse voltage with a voltage comparator circuit.

11. The method as in claim 10 , comprising adjusting the threshold voltage with a controller associated with the charging circuit.

12. The method as in claim 9 , comprising disconnecting the charging circuit from the battery with a switching device that is activated upon detection of the reverse voltage at the threshold value.

13. The method as in claim 12 , comprising adjusting a switching hysteresis of the switching device with a controller associated with the charging circuit.

14. The method as in claim 9 , further comprising communicating detection of the reverse voltage above the threshold value from the charging circuits to a central wind turbine controller.

15. The method as in claim 9 , further comprising communicating detection of the reverse voltage above the threshold value from the charging circuits to a central site controller common to a plurality of wind turbines.

16. The method as in claim 9 , wherein the varistor comprises a MOV (metal-oxide varistor).

17. The method as in claim 12 , wherein, when the switching device is activated to disconnect the charging circuit from the battery, the surge suppressor protects a voltage comparator circuit of the charging circuit from leakage inductance from the pitch drive, the voltage comparator circuit configured to detect the reverse voltage condition.

Assignees

• Gen Electric

Inventors

• Shen Longhui
• Hudnall David Ray
• Wang Jianquan

Classifications

• F03D7/0268

  Parking or storm protection · CPC title

• Y02E10/723

  Cross-Sectional Technologies · mapped topic

• F03D80/82

  of electrical components · CPC title

• F05B2260/845

  Redundancy · CPC title

• F03D7/0224 Primary

  Adjusting blade pitch · CPC title