Method for determining an efficiency and/or for calibrating a torque of a drivetrain, in particular of a wind turbine

Patent metadata

Field	Value
Publication number	US-11828266-B2
Application number	US-201915733585-A
Country	US
Kind code	B2
Filing date	Mar 1, 2019
Priority date	Mar 8, 2018
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

A method for determining an efficiency and/or calibrating a torque of a drivetrain comprises two tests. The drivetrain has a motor-side end at a main shaft connectable to a motor and a generator-side end, with a generator arranged between the ends. In a first test, the motor-side end of the drivetrain is driven. A variable dependent on the main shaft torque is determined at the motor-side end of the drivetrain and an electrical power Pelec is determined at the generator-side end of the drivetrain. In a second test, the generator-side end of the drivetrain is driven and the variable dependent on the main shaft torque is determined at the motor-side end and the electrical power is determined at the generator-side end. An efficiency and/or calibration parameters is/are determined from the electrical power values and the variables dependent on the main shaft torque determined in the first test and second tests.

First claim

The invention claimed is:

1. A method for determining an efficiency of a drivetrain of a wind turbine, wherein the drivetrain has a motor-side end on a main shaft connectable to a motor and a generator-side end, between which ends a generator is arranged, the method comprising:
performing a first test, wherein in the first test, the motor-side end of the drivetrain is driven and a variable dependent on a main shaft torque is determined at the motor-side end of the drivetrain and an electrical power P elec is determined at the generator-side end of the drivetrain;
performing a second test, wherein in the second test, the generator-side end of the drivetrain is driven, and the variable dependent on the main shaft torque is likewise determined at the motor-side end and the electrical power P elec is determined at the generator-side end; and
determining at least one of an efficiency or one or more calibration parameters from the electrical power values and the variables dependent on the main shaft torque determined in the first test and in the second test, using at least one predetermined assumption.

2. The method according to claim 1 , wherein an assumption for determining the efficiency or for calibrating a torque measurement is the assumption that the efficiency of the first test is equal to the efficiency of the second test.

3. The method according to claim 1 , wherein an assumption for determining the efficiency or for calibrating a torque measurement is the assumption that a power loss of one of the two tests is a fraction of a total power loss of the two tests.

4. The method according to claim 1 , wherein to determine the torque of the main shaft, the variable dependent on the main shaft torque is measured using a sensor, and/or an angular position θ of the main shaft or a rotational speed ω of the main shaft is measured.

5. The method according to claim 1 , wherein a mechanical power is determined from the variable dependent on the main shaft torque for the first and for the second test.

6. The method according to claim 1 , wherein, to determine the electrical power, a voltage and a current are measured at the generator-side end between the generator and a converter connected to the same, or at the side of the converter facing away from the generator.

7. The method according to claim 1 , wherein a test power loss is determined for the first test and for the second test respectively, wherein these two determined test power losses are added together for a total power loss, and wherein the efficiency is calculated using the total power loss.

8. The method according to claim 4 , wherein, to determine the variable dependent on the main shaft torque, a measurement signal of the sensor is evaluated, which is arranged at an output shaft of the motor, or at a shaft adapter between the output shaft of the motor and the main shaft.

9. The method according to claim 1 , wherein different operating points of the drivetrain are approached during the first test, and that different operating points of the drivetrain are approached during the second test.

10. The method according to claim 1 , wherein the generator-side end of the drivetrain is driven in the second test in such a way that the variable dependent on the main shaft torque in the second test is equal to the variable dependent on the main shaft torque determined in the first test.

11. The method according to claim 1 , wherein the generator-side end of the drivetrain is driven in such a way in the second test that the electrical power in the second test is equal to the electrical power determined in the first test.

12. The method according to claim 1 , wherein, by using the variable dependent on the main shaft torque, a mechanical power P mechA and P mechB is determined as a function of two constants a and b for the first test and for the second test, respectively,

P
~

mech
.
A

=

∫

θ
0

θ
A

(

a
⁢
ε

+
b

)

⁢
d
⁢
θ

t
A

P
~

mech
.
B

=

∫

θ
0

θ
B

(

a
⁢
ε

+
b

)

⁢
d
⁢
θ

t
B

and based on:
P mech.A −P elec.A =k ( P elec.B −P mech.B )
and
P mech.A +kP mech.B =kP elec.B +P elec.A

where k is a correlation between losses of the first test and of the second test, wherein calibration parameters a and b for determining a torque are determined using:
T=aε+b

where T is the torque and c is the measured variable dependent on the main shaft torque.

13. The method according to claim 1 , wherein each value of the main shaft torque determined in the first test and the second test defines a different power level of the drivetrain.

14. The method according to claim 1 , wherein starting from a predetermined efficiency, the one or more calibration parameters are determined, then efficiencies are determined for at least two power levels and subsequently the one or more calibration parameters are determined again, and the last two steps are repeated until the deviation between the last and the preceding determination is smaller than a predetermined value.

15. The method according to claim 1 , wherein the one or more calibration parameters are determined using the method of least squares.

16. A method for calibrating a torque measurement of a drivetrain of a wind turbine, on a test rig, wherein the drivetrain has a motor-side end on a main shaft connectable to a motor

Assignees

• Fraunhofer Ges Forschung

Inventors

• Zhang Hongkun
• Eich Norbert
• Pilas Martin
• Wenske Jan

Classifications

• F03D17/00 Primary

  Monitoring or testing of wind motors, e.g. diagnostics (testing during commissioning of wind motors F03D13/30) · CPC title

• F03D15/00

  Transmission of mechanical power · CPC title

• G01L3/242

  by measuring and simultaneously multiplying torque and velocity · CPC title

• G01L3/26

  Devices for measuring efficiency, i.e. the ratio of power output to power input · CPC title

• G01L5/0095

  measuring work or mechanical power · CPC title