High dynamic range torque control

All measured signals differ more or less from the true physical value (general example image). HDRT aims to minimize error and noise of measured motor phase currents by adjusting current sensor sensitivity by the means of a low noise amplifier prior to analog-to-digital conversion.

Torque control is the most important single instrument present in modern motor drives. All operations drive does, are handled finally by a torque controller - even if motor is being operated in velocity or positioning modes.

High dynamic range torque control a.k.a. HDRT is a torque control technology built in VSD-E/XE series and Argon servo drive series. HDRT yields approximately 14 bits of torque resolution which is 16 times higher compared to standard 10 bit torque resolution found from an average drive. HDRT has been implemented by using on-the-fly adjusting current sensor gain control combined with low noise electronics and at least 16 bit digital signal path inside the drive.

Contributions

• Smoother, less jittering motion when combined with high resolution feedback
• Quieter operation, reduced noise from motor
• Allow supporting wide power range of motors within single drive