Motor drive with velocity-second compensation

An electronic line shaft, comprising:

• a signal source operable to generate a reference velocity signal;
• a master drive unit operable to receive the reference velocity signal, comprising:
• a motor;
• a motor controller operable to provide a torque input signal to the motor;
• a velocity compensator operable to receive the reference velocity signal, determine a derivative of the reference velocity signal, and generate a velocity compensation signal based on the derivative;
• an adjustor operable to adjust the reference velocity signal as a function of the velocity compensation signal;
• and
• a velocity regulator operable to compare the adjusted reference velocity signal to a feedback velocity signal and provide an output signal to the motor controller for adjusting the torque input signal based on the comparison.

A method for controlling a motor, comprising:

• providing a torque input signal to the motor;
• generating a reference velocity signal;
• generating a velocity compensation signal based on a derivative of the reference velocity signal;
• adjusting the reference velocity signal based on the velocity compensation signal;
• and
• comparing the adjusted reference velocity signal to a feedback velocity signal;
• and
• adjusting the torque input signal based on the comparison.

A printing system including a plurality of printing stations for processing a web, comprising:

• a signal source operable to generate a reference velocity signal;
• and
• a plurality of drive units for moving the web through the printing stations in accordance with the reference velocity signal, each of the drive units comprising:
• a motor;
• a motor controller operable to provide a torque input signal to the motor;
• a velocity compensator operable to receive the reference velocity signal, determine a derivative of the reference velocity signal, and generate a velocity compensation signal based on the derivative;
• an adjustor operable to adjust the reference velocity signal as a function of the velocity compensation signal;
• and
• a velocity regulator operable to compare the adjusted reference velocity signal to a feedback velocity signal and provide an output signal to the motor controller for adjusting the torque input signal based on the comparison.