Lenze i55AE155F

8.2.2 V/f characterisc control (VFC closed loop)
The V/f characterisc control with feedback (VFC closed loop) can be used if an asynchronous
motor with motor encoder is connected to the inverter.
The speed feedback leads to the following advantages:
•
Staonary speed accuracy
•
Improved dynamics compared to the V/f characterisc control without feedback (VFC
open loop) or to the encoderless vector control (SLVC)
•
Suitability for group drives
Precondions
•
The V/f characterisc control (VFC closed loop) is only suitable for asynchronous motors.
•
The V/f characterisc control (VFC closed loop) requires a feedback of the speed. A motor
encoder must be connected to the inverter and set as feedback system for the motor con-
trol.
•
This seng is not made automacally if a motor is selected from the motor catalog.
•
For required sengs see chapter "HTL encoder". ^ 496
•
If you want to actuate a drive with a square-law V/f characterisc: please always check
whether the corresponding drive is suitable for operaon with a square-law V/f character-
isc!
•
From the motor nameplate data, at least the rated speed and rated frequency must be
entered, so that the inverter can calculate the correct number of pole pairs. 4Motor data
^ 164
•
The motor must only be actuated above the rated motor frequency/rated voltage if this is
expressly approved by the motor manufacturer!
Details
This motor control type is acvated by seng 0x2C00 (P300.00) = " V/f characterisc control
(VFC closed loop) [7]".
•
0x2B00 (P302.00) provides dierent characterisc shapes.
•
Liming factors for the V/f characterisc are rated mains voltage 0x2540:001 (P208.01),
minimum frequency 0x2915 (P210.00) and maximum frequency 0x2916 (P211.00).
•
The slip compensaon is deacvated in this motor control type. In case of V/f characteris-
c control with feedback, the slip is calculated and injected by the slip regulator. 4Slip
controller ^ 210
Next steps
•
The inverter provides dierent funcons by means of which the drive behaviour can be
further opmised.4Opmisaon of motor control ^ 182
•
An opmisaon of the control loops is not mandatory for this motor control type but may
lead to a
beer control mode. 4Opmisaon of the control loops ^ 193
Motor control
Motor control selecon
V/f characterisc control (VFC closed loop)
172