Proposals for a practical calibration method for mechanical torque measurement on the wind turbine drive train under test on a test bench

Abstract

The mechanical torque input into the wind turbine drive train is a very useful measurement for tests performed on a test bench. To ensure the accuracy and the reliability, an accurate calibration of the torque measurement must be carried out and repeated within a certain period of time. However, owing to the high torque level and large structure size, such a calibration is both expensive and time consuming. To overcome this challenge, a new calibration method is proposed here. The method is based on the electrical power measurement, where a high level of accuracy is much easier to achieve. With the help of a special test process, a relationship between the torque‐measuring signal and the electrical power can be established. The process comprises two tests with the drive train running in different operating modes. The calibration is possible by carrying out the same test process on several different torque levels. Detailed uncertainty analysis of the method is presented, whereby the uncertainty can be calculated by means of matrix operation and also numerically. As a demonstration, the implementation of the method on a test bench drive train that contains two 5‐MW motors in tandem with the motors operating in a back‐to‐back configuration is also presented. Finally, some variations on the method and possible ways of achieving better accuracy are discussed.

Evaluation of a Hardware-in-the-loop Test Setup Using Mechanical Measurements with a DFIG Wind Turbine Nacelle

“…The measurement utilized in this work is based on shear strain measurements, being enhanced by a cross-coupling compensation (bending and shear loads) and calibration as described in section 4. Further application-oriented research on efficient calibration methods for mechanical torque measurements on WEC and test bench drive trains is ongoing, and promising solutions are being developed [7] [8]. Currently, a calibrated torque measurement is only available for a range up to 1.1 MNm [8], and further work is in progress for calibration up to a higher range as done in the project WindEFCY [9].…”

A FEM-Based Optimization Method for Driving Frequency of Contactless Magnetoelastic Torque Sensors in Steel Shafts

“…Measuring the torque in mechanical shafts made of steel is a common challenge found in various industrial applications. Some examples of these applications include marine propulsion systems [ 1 , 2 ], turbine generators [ 3 , 4 , 5 ], robotics [ 6 , 7 , 8 , 9 , 10 ], and automotive [ 11 , 12 , 13 , 14 ] and electromobility applications [ 15 , 16 , 17 ]. Due to the rotation of a mechanical shaft under normal working conditions, powering a typical strain-gauge based torque sensor while collecting data is very challenging [ 3 ].…”