Vector Control - ABB ACS580 Firmware Manual

See also section Operating modes of the drive
IR compensation for scalar motor control
IR compensation (also known as
voltage boost) is available only when
the motor control mode is scalar. When
IR compensation is activated, the drive
gives an extra voltage boost to the
motor at low speeds. IR compensation
is useful in applications, such as
positive displacement pumps, that
require a high break-away torque.
In vector control, no IR compensation is
possible or needed as it is applied automatically.
Settings
• Menu - Primary settings - Motor - IR compensation
• Parameters 97.13 IR compensation
(page 338)
• Parameter group


Vector control

Vector control is the motor control mode that is intended for applications where high
control accuracy is needed. It requires an identification run at startup. Vector control
cannot be used in all applications, eg sine filters.
The switching of the output semiconductors is controlled to achieve the required
stator flux and motor torque. The output frequency is changed only if the actual
torque and stator flux values differ from their reference values by more than the
allowed hysteresis. The reference value for the torque controller comes from the
speed controller or directly from an external torque reference source.
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 main difference between traditional control and vector control is that torque
control operates at the same time level as the power switch control. There is no
separate voltage and frequency controlled PWM modulator; the output stage
switching is wholly based on the electromagnetic state of the motor.
The best motor control accuracy is achieved by activating a separate motor
identification run (normal ID run).
28 Frequency reference chain
(page 89).
Motor voltage
IR compensation
No compensation
(page 335) and 99.04 Motor control mode
(page 226).
Program features 111
f (Hz)