Hitachi SJ Series User Manual page 246

Chapter 12
12.9.14 Use V/f control with sensor
(reducing torque characteristics)
Q
• To conduct a V/f control with a high revolution
accuracy by use of the revolution-speed feedback
of a motor.
• To output the revolutions of fans and/or pumps
exactly in accordance with their respective speed
characteristics.
A
• The feedback of the encoder signal from the motor
allows highly accurate frequency control.
• For the adjustment of V/f control (reducing torque
characteristics), see "12.9.3 Drive with V/f control
(reducing torque characteristics)."
Output
Deviationε
+
frequency
-
Parameter
Item
Control mode
Control with sensor
slip compensation
P gain
Control with sensor
slip compensation
I gain
PI control
+
1
Kp (1+ )
+
Ti•S
Kp: proportional gain setting; Ti: integral time; s: operator; ε: deviation
Ki: integral gain setting (Ki = Ti/Kp)
Parameter Data
[AA121] 05
[Hb170] 0~1000(%)
[Hb171] 0~1000(%)
12-9-29
!
• When [CA-90] = 02, Input terminals [A] and [B] are
switched to the terminals for feedback control.
When [CA-90] ≠ 02, terminals [EA] and [EB] of the
feedback option P1-FB are enabled.
See "12.9.17 Use encoder."
• In the V/f control with feedback (FB), a correction of
PI control is conducted on the command frequency
for the fed-back frequency to control the motor.
Control
frequency
Frequency-volt
age control
To use V/f control with sensor (reducing torque
characteristics).
This is the P gain for the slip compensation of
control with sensor.
This is the I gain for the slip compensation of control
with sensor.
Inverter Function
M
Feedback
Description