Mitsubishi Electric FR-A820-00046 Instruction Manual page 261

Parameters
Motor-generated torque (TM), slip angular velocity (ωs) and the motor's secondary magnetic flux (Ф2)
can be found by the following calculation:
TM ∼ Ф2 × iq
Ф2 = M × id
ωs = (r2/L2 × iq/id), where L2: secondary inductance
L2 = l2 + M
Vector control provides the following advantages:
● Excellent control characteristics when compared to V/F control and other control techniques,
achieving the control characteristics equal to those of DC machines.
● Applicable to fast response applications with which induction motors were previously regarded
as difficult to use.
Applications requiring a wide variable-speed range from extremely low speed to high speed,
frequent acceleration/deceleration operations, continuous four-quadrant operations, etc.
● Allows torque control (when induction motors are used).
● Allows servo-lock torque control which generates a torque in the motor shaft while stopped. (Not
available under Real sensorless vector control.
ω ∗
+
-
ω FB
Fig. 5-4:
FR-A800
φ 2
Magnetic
id
∗
+
flux
control
-
id
iq
∗
+
Speed
control
ω 0
+
ω FB
+
ω s
iq
Slip
calculation
φ 2
Speed estimation
Block diagram of Real sensorless vector control
Pre-
excitation Vd
current
control
Torque Vq
current
control
-
iq
id
iq
iq
Magnetic
id
flux
Vd
calculation
Vq
Control method
IM
PWM
modulation
Output
voltage
conversion
ω 0
Current
conversion
I002502E
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