Vector Ride-Through - WEG CFW-11 Programming Manual

Description:
The parameter P0332 sets the minimum time that the inverter will wait to activate the motor again, which is
necessary for the motor demagnetization.
In the Ride-Through function case, the time is counted starting from the line drop. However in the Flying Start
function actuation, the counting begins after the "Run/Stop=Run" command is given.
For the correct operation, this time must be adjusted to twice the motor rotor constant (refer to the table available
at P0412 in the section 11.8.5.

12.7.4 Vector Ride-through

Different from the V/f mode, in the vector mode the Ride-Through function tries to regulate the DC link voltage
during the line failure, without interruption or fault storing. The energy necessary to keep the aggregate working
is obtained from the motor kinetic energy (inertia) by means of its deceleration. Thus, at the line return the motor
is reaccelerated to the speed defined by the reference.
After the line failure (t0), the DC link voltage (U
load condition, being able to reach the undervoltage level (t2) if the Ride-Through function is not working. The
typical necessary time for this to occur, with rated load, is from a magnitude of 5 to 15 ms.
With the Ride-Through function active, the line loss is detected when the U
"DC Link Power Loss" value (t1), defined at the parameter P0321. The inverter initiates a controlled deceleration
of the motor immediately, regenerating energy to the DC link in order to keep the motor operating with the U
voltage regulated at the value "DC Link Ride-Through" (P0322).
In case that the line does not return, the aggregate remains in this condition the longest possible time (depends
on the energetic balance) until undervoltage (F021 in t5) occurs. If the line returns before the undervoltage
occurrence (t3), the inverter will detect its return when the U
level, defined at the parameter P0323. The motor is then reaccelerated, following the adjusted ramp, from the
actual speed value to the value defined by the speed reference (P0001) (refer to the figure 12.7).
Nominal
Return (P0323)
Loss (P0321)
Ride-Through (P0322)
Undervoltage (75 %)
) starts diminishing according to a rate depending on the motor
d
U
d
t0 t1 t2
Figure 12.7 - Ride-Through function actuation in vector mode
Functions Common to All the Control Modes
voltage reaches a value below the
d
voltage reaches the "DC Link Power Back" (t4)
d
t3
d
F021
t
(t)
t4 t5
12-15
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