Variable speed drive and torque sensor

A method for controlling a variable speed drive of an electric motor, the variable speed drive being connected to a torque sensor for sensing a torque supplied by the electric motor, the method comprising:

• performing, by the electric motor, a predetermined torque sequence, wherein the predetermined torque sequence has a theoretical predetermined torque sequence with a specific profile and comprises chirp torque oscillations, and wherein the chirp torque oscillations comprise a pseudo sinusoidal signal whose frequency varies over time;
• measuring, by the torque sensor, a measured torque sequence corresponding to the predetermined torque sequence performed by the electric motor;
• comparing the theoretical predetermined torque sequence and the measured torque sequence;
• and
• as a result of the comparison, determining one or more torque sensor transfer function parameters for a torque sensor transfer function which is configured to output measurement of torque supplied by the electric motor for use by the variable speed drive based on the measured torque from the torque sensor and the one or more torque sensor transfer function parameters.