Mitsubishi Electric FR-E800 Series Instruction Manual page 97

Block diagram of Vector control
φ 2
ω *
+
-
ω FB
ω FB
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.
96
4. Control Method
4.1 Vector control and Real sensorless vector control
*
Magnetic
id
+
flux
control
-
id
*
iq
+
Speed
control
-
iq
+ ω 0
+
ω s
iq
Slip
calculation
φ 2
Magnetic
calculation
Pre-excitation
Vd
current
control
Torque
Vq
current
control
id
iq
id
flux
Encoder
PWM
modulation
Output
voltage
conversion
ω 0
Current
conversion
I M