Posted to News on 5th Feb 2007, 00:00
New technique offers improved stepper control
Ever Elettronica uses its proprietary F4D2 (fast forward feed full digital drive) servo-step technology to regulate the torque, speed and position loops of stepper motors - synchronous motors with a high number of poles - by means of fully digital drives. This technology, the company claims, is the core of important innovations in control methods for stepper motors.
The patented F4D2 feedback algorithm is implemented by means of a DSPC controller on stepper motors with four phases and 50 poles and provides a fast motor's phase current regulation by calculating the duration of the PWM cycles and the direction of the current vector in the coordinating system of the motor's stator. This saves the usual double computation of data and results conversion from stator's to rotor's coordinates and vice-versa.
The control by discrete motor steps is now replaced with a sinusoidal winding excitation without parasitic harmonics that, with the new closed loop control method, is always synchronous with the actual position of the rotor. Thanks to the high chopper frequency obtained through the F4D2 technology, the highest torque is obtained from the motor at any speed, with a regular and silent rotation. The high frequency of the current regulation cycle in turn allows the torque, speed and position loops to be quickly closed.
