Mitsubishi Electric FR-A820-00046 Instruction Manual page 235

Parameters
ω ∗
+
-
ω FB
Fig. 5-5:
Speed control
Speed control operation is performed to zero the difference between the speed command (ω*) and
actual rotation value detected by encoder (ω
transferred to the torque current controller as a torque current command (i
Torque current control
A voltage (V
found by the speed controller.
Magnetic flux control
The magnetic flux (Ф2) of the motor is derived from the excitation current (id). The excitation current
command (i
Excitation current control
A voltage (V
(i *).
d
Output frequency calculation
Motor slip (ωs) is calculated on the basis of the torque current value (i
output frequency (ω
the encoder.
The above results are used to make PWM modulation and run the motor.
FR-A800
∗
φ 2
Magnetic
id
+
flux
control
-
id
∗
iq
Speed
control
+ ω 0
ω FB
+
ω s
iq
Slip
calculation
φ 2
Block diagram of Vector control
) is calculated to flow a current (i
q
*) is calculated to use that motor magnetic flux (Ф2) as a predetermined magnetic flux.
d
) is calculated to flow a current (i
d
) is found by adding that slip (ωs) to the feedback (ω
0
Pre-
excitation Vd
current
control
Torque
Vq
+
current
control
-
iq
Magnetic id
flux
calculation
). At this time, the motor load is found and its result is
FB
) which is identical to the torque current command (i
q
) which is identical to the excitation current command
d
Control method
PWM
modulation
Output
voltage
conversion
ω 0
id
Current
iq
conversion
*).
q
) and magnetic flux (Ф2). The
q
) found by a feedback from
FB
IM
Encoder
I002503E
*)
q
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