Frequency Compensation Function - Mitsubishi Electric FR-A700 Technical Manual

2.19 Frequency compensation function

2.19.1 Slip compensation [Pr. 245 to 247]
Motor speed can be kept constant by estimating motor slip from output current under V/F control, Simple magnetic flux vector
control (only in ), and General-purpose magnetic flux vector control (only in
F700
[Pr.] Name
245 Rated slip
246 Slip compensation time constant
Constant-power range slip
247
compensation selection
Slip compensation is valid when the motor rated slip
calculated by the following expression is set in [Pr. 245] .
Slip compensation is not made when [Pr. 245 = 0, 9999].
(Synchronous speed at base
frequency)
Rated slip =
Synchronous speed at base frequency
When performing slip compensation, the output frequency
may become greater than the set frequency. Set the [Pr. 1
Maximum frequency] value a little higher than the set
frequency.
common
(common)
Initial Value Setting Range
0.01 to 50%
9999
0, 9999
0.5s 0.01 to 10s
9999
9999
[Pr.245 to 247] settings are invalid under Advanced
magnetic flux vector control in
sensorless vector control in
since slip compensation is performed under these controls.
Rated
-
speed
×
When encoder feedback control is performed by
100 [%]
[Pr. 245 to Pr. 247] settings are invalid.
391
.)
E700 D700
Description
Used to set the rated motor slip.
No slip compensation
Used to set the slip compensation response
time. When the value is made smaller, response
will be faster. However, as load inertia is greater,
a regenerative overvoltage fault (E.OV1 to 3) is
more liable to occur.
Slip compensation is not made in the constant
0 power range (frequency range above the
frequency set in ([Pr. 3]).
Slip compensation is made in the constant power
range.
PARAMETER
, Real
A700 E700
, and vector control
A700
,
A700
2