
52 Program features
Vector control
Vector control is the motor control mode which is intended for applications where high
control accuracy is needed. It offers better control over the whole speed range, in
particular in applications where slow speed with high torque is needed. It requires a
motor identification at startup. Vector control cannot be used in all applications, e.g.
there are multiple motors connected to single drive.
The switching of the output semiconductors is controlled to achieve the required
stator flux and motor torque.
Motor control requires measurement of the DC voltage and two motor phase
currents. Stator flux is calculated by integrating the motor voltage in vector space.
Motor torque is calculated as a cross product of the stator flux and the rotor current.
By utilizing the identified motor model, the stator flux estimate is improved. Actual
motor shaft speed is not needed for the motor control.
The best motor control accuracy is achieved by activating a separate motor
identification run (ID run).
Speed control performance figures
on page
.
Settings and diagnostics
(page
Events: -
Reference ramping
Acceleration and deceleration ramping times can be set individually for speed, torque
and frequency reference.
With a speed or frequency reference, the ramps are defined as the time it takes for
the drive to accelerate or decelerate between zero speed or frequency and the value
defined by parameter (
or
). The user can switch between two preset ramp
sets using a binary source such as a digital input. For speed reference, also the
shape of the ramp can be controlled.
With a torque reference, the ramps are defined as the time it takes for the reference
to change between zero and nominal motor torque (
.
Special acceleration/deceleration ramps
The acceleration/deceleration times for the jogging function can be defined
separately; see section
.
The change rate of the motor potentiometer function (page
) is adjustable. The
same rate applies in both directions.
A deceleration ramp can be defined for emergency stop (“Off3” mode).
ACS180 FW.book Page 52 Tuesday, March 9, 2021 2:25 PM