IF08CZ10 April, 2019 - 48 -
CIRCUIT OPERATION (cont’d)
V/f Control
(1) Frequency reference (F_P)
The frequency reference is determined by the speed reference signal (SP_R) and the slip
frequency, when slip compensation is used.
The frequency is compensated by the change of the Q axis current for the control stability.
(2) Q axis voltage reference (EQ_R)
The Q axis voltage reference is proportional to the frequency reference and flux reference.
This voltage may be compensated by the Q axis current for auto torque boost, when advanced V/f control is
used. The V/f rate can be changed by the selected V/f pattern.
The Q axis voltage is compensated by the change of the D axis current for the control stability.
(3) D axis voltage reference (ED_R)
The D axis voltage reference is used for low speed torque boost normally. This voltage can also be
compensated based upon Q axis current, when advance V/f control is used.
Speed
reference
SP_R
−
+
+
+
+
VF_FCMP_A
VF_FCMP_AT
VF_WSCMP_EN
CS_MOTOR_RPM
utomatic
Tor q ue
boost
FL_R
Start torque
boost
VF_LSP_VBST
VF_LSP_VBSTSP
MI_ID_BASE
MI_R1_SET
MI_L_CMP
VF_TRQBST_GAIN
VF_SP_TRQBST
V/f
pattern
CS_KS_FAI
CS_SP_BASE
FLT_FLX
F_P
+
+
ED_R
IQ_F
CS_VF_MODE
CS_VF_CURVE
CS_FP1
~
5
CS_VP1
~
5
Voltage
stabilization
control
VF_DVCMP
A, VF_DVCMP_AT
VF_DVCMP_GAIN, VF_DVCMP_LSP
ID_F
+
(Simple V/f)
(Advancced V/f)
Frequency
stabilization
control
Stall
prevention
control
Slip
frequency
-
+
+
VF_STL_P
VF_STL_W1
VF_LMT_STL
VF_FLT_STL
VF_STLPOINT
Overcurrent
control
VF_CP_ILIM
VF_FLT_ILIM
Modulation
ratio
EQ_R
-
VF_DVCMP
VF_FCMP
Flux reference
Modulation
ratio
VF_WSCMP
+
+
+
VF_STLCMP
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