Technical data

20
Sensorless control of permanent
magnet synchronous motors
In brushless motor control, the exact angular
position of the rotor must be known at all times
for the drive to commutate the inverter phases.
The conventional method for tracking rotor
position is to incorporate an encoder or resolver
inside the servomotor to provide the drive with the
necessary electrical signals. This, however, requires
extra cabling, data interfaces and controls.
Thanks to innovative technology, Agile drives can
control brushless servomotors without the need
for sensors, eliminating the cost of superfluous
components, wiring, interfaces and controls. Agile
drives use efficient algorithms to calculate the
instantaneous angular position of the motor shaft
from measurements of the current absorbed by
the motor. This gives significant savings in costs,
eliminates the criticalities inherent in sensors,
simplifies the control system and reduces energy
consumption by permitting a more efficient motor
architecture to be used.
By combining analytic techniques to reconstruct
the electrical status of the motor and functional
analyses of its magnetic circuit, Agile drives
provide effective vector control of torque.
Speed or
torque
reference
Agile
Vector
control
PWM Power
Position
reconstruction
Sensorless
PMSM
Speed
Torque
Calculated
position
Agile
Power
NO feedback
Servomotor