Mitsubishi Electric 800 Series Instruction Manual (Function page 104

Block diagram of Vector control
φ 2
Magnetic
flux
control
*
ω
+
Speed
- control
ω FB
+
ω FB
+
ω s
Speed control operation is performed to zero the difference between the speed command (ω*) and actual rotation value
Speed control detected by encoder (ωFB). At this time, the motor load is found and its result is transferred to the torque current
controller as a torque current command (iq*).
Torque current A voltage (Vq) is calculated to flow a current (iq) which is identical to the torque current command (iq*) found by the
control speed controller.
Magnetic flux The magnetic flux (Φ2) of the motor is derived from the excitation current (id). The excitation current command (id*) is
control calculated to use that motor magnetic flux (Ф2) as a predetermined magnetic flux.
Excitation current A voltage (Vd) is calculated to flow a current (id) which is identical to the excitation current command (id*).
control
Output frequency Motor slip (ωs) is calculated on the basis of the torque current value (iq) and magnetic flux (Φ2). The output frequency
calculation (ω0) is found by adding that slip (ωs) to the feedback (ωFB) found by a feedback from the encoder.
The above results are used to make PWM modulation and run the motor.
Pre-excitation
*
id
+
current
control
-
id
Torque
*
iq
+
current
control
-
iq
ω 0
iq
Slip
calculation
φ 2
Magnetic
flux
calculation
PWM
modulation
Vd
Output
voltage
conversion
Vq
ω 0
id
Current
iq
conversion
id
4.1 Vector control and Real sensorless vector control
1
I M
2
Encoder
3
4
5
6
7
8
9
10
103
4. Control Method