D-Q Axis Current Control - Toshiba T300MVi MEDIUM VOLTAGE Instruction Manual

CIRCUIT OPERATION (cont'd)

D-Q Axis Current Control

The figure on the following page shows the block diagram of D-Q axis current control.
This system controls the current of an induction motor by separating it into a magnetic flux (Field)
component and a torque component. This drive controls the current on the D-Q coordinates. It can control
the current to an AC motor as a DC value, achieving high performance control irrespective of output
frequencies.
(1) ID (Field current) control
A magnetic flux reference is generated based upon the speed reference. This and the field current
setting (MI_ID_BASE) are used to generate an ID reference. This ID reference and the ID feedback signal
are input into a PI controller. The output of this controller is the ED_R (Field voltage reference). Optional
Inductance (L) compensation can also be used (ACR_WL). If used, this value is combined with the PI
controller output to create the ED_R.
(2) IQ (Torque current) control
The torque reference, which is the result of the previously mentioned speed control, is input and
divided by magnetic flux to obtain an IQ reference. This IQ reference and IQ feedback signal are input into a
PI controller. The output of this controller is the EQ_R (Torque voltage reference). An induction voltage
compensation (ACR_E2) and L compensation (ACR_WL) may also be used. If used these values are
combined with the output of the PI controller to create the EQ_R.
M a g n e tic flu x
re fe re n ce
F L _ R
T o rq u e
re fe re n ce
T _ R
F ie ld cu rre n t
se ttin g
M I_ ID _ B A S E
F lu x fu n ctio n
D-Q Axis Current Control
A C R _ E 2
F re q u e n cy
+
IQ _ R
-
IQ
lim it
IQ _ F
<IQ limit>
A C R _ A : A n ti-o v e rsh o o t
A C R _ P : P ro p o rtio n a l
A C R _ W 1 : R e sp o n se ta rg e t
ID _ R
+
-
ID
lim it
ID _ F
- 39
< Integral>
< P rop ortional>
+
+
+
+ +
+
-
ID _ R
< A nti-ov ershoot>
F re q u e n cy A C R _ W L
IQ _ R
< Integral>
< P roportion al>
-
+
+ +
-
< A nti-ov ershoot>
E Q _ R
E D _ R