4-92
4-2 Function Mode
4
Functions
P/PI Switching Function
•This function allows you to switch the control (compensation) method for the speed control system
between proportional integral compensation and proportional compensation, when "sensorless
vector control", "0-Hz sensorless vector control", or "sensor vector control" is selected as the
control method.
•If P/PI switching is selected in the multi-function input selection, proportional integral compensation
is enabled while the signal is off; proportional compensation is enabled while the signal is on.
If P/PI switching is not selected in multi-function inputs 1 to 8 (C001 to C008), proportional integral
compensation is enabled.
Normally, the Inverter performs proportional integral compensation
(PI control) for speed control so that the difference between
frequency reference and actual rpm becomes zero. If one load is
operated by several motors, however, proportional control (P
control) may be required. To enable proportional control (P
control), allocate the P/PI switching function to any of multi-
function input terminals 1 to 8 (set "43" in any of C001 to C008)
via the Digital Operator, and turn on the terminal. If you choose to
enable proportional control, set a "KPP" value in H052 (P
proportional gain).
The relationship between the KPP value and speed change ratio
is expressed broadly in the following formula:
Parameter No. Function name Data Default setting Unit
A044/A244/A344
V/f characteristics
selection
03: SLV (Sensorless vector control)
(A344 is blank.)
04: 0SLV (0 Hz sensorless vector
control) (A344 is blank.)
05: V2 (Sensor vector control)
00
C001 to C008
Multi-function inputs
1 to 8 selection
43: PPI (P/PI switching)
H005/H205 Speed response 0.001 to 80.000 1.590
H050/H250 PI proportional gain 0.0 to 1000.0 100.0 %
H051/H251 PI integral gain 0.0 to 1000.0 100.0 %
H052/H252 P proportional gain 0.01 to 10.00 1.00
The relationship between speed change ratio and speed error is
expressed broadly in the following formula:
Torque
100%
0
P control
PI control
(A)
rpm
(Speed change ratio)
=
10
(KPP set value)
%
(Speed change ratio) =
Speed error at rated torque (A)
Synchronous rpm at base frequency
× 100%
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