47
Fig.6-37 Offset of output voltage
The relationship between analog input and offse voltage
is as follows:
-10V~0V/4mA of VAI is corresponding to offset voltage
–V/F.
10V/20mA of VAI is corresponding to offset voltage
V/F.
Output voltage VO=V/F+Vb.
Note
Output offset voltage of AI can be only valid in V/F
control mode.
6.12 Group b2
b2.00 Carrier wave frequency 2.0
~
15.0kHz
【
8kHz
】
Drive’s type and carrier wave frequency(CWF)
Drives power
Default CWF value
2.2
~
5.5 kW
10kHz
7.5
~
55 kW
8kHz
55
~
250 kW
2kHz
Note:
1.The carrier wave frequency will affect the noise when
motor running,generally the carrier wave frequency is
supposed to set as 3~5KHz.For some special situation
where require operating mutely,the carrier wave
frequency is supposed to set as 6~8KHz.
2
.
When set the carrier wave frequency larger than
defaultvalue,then the power of drive need to derate 5%
by every increase of 1KHz.
b2.01Auto adjusting of CWF 0
~
1
【
0
】
0
:
Disable
1
:
Enable
b2.02 Voltage adjustment
selection
000
~
111H
【
001H
】
b2.03 Overvoltage point at
stall
120
~
150%
【
140.0%
】
During deceleration, the motor’s decelerate rate may be
lower than that of drive’s output frequency due to the
load inertia. At this time, the motor will feed the energy
back to the drive, resulting in the voltage rise on the
drive's DC bus. If no measures taken, the drive will trip
due to over voltage.
During the deceleration, the drive detects the bus voltage
and compares it with the over voltage point at stall
defined by b2.03. If the bus voltage exceeds the stall
overvoltage point, the drive will stop reducing its output
frequency. When the bus voltage become lower than the
point, the deceleration continues, as shown in Fig.6-36.
The hundred’s place is used to set overmodulation
function of V/F control.For vector control,the
overmodulation function will be always
enable.Overmodulation means when the voltage of
power grid is low for long term(Lower than 15% of
rated voltage),or is overload working for long term,then
the drives will increase the use ratio of its own bus
voltage to increase output voltage.