Mitsubishi Electric 800 Series Instruction Manual page 173

Speed control under Real sensorless vector control, vector control, PM sensorless vector
control
No. Condition
Hunting (vibration or
acoustic noise) occurs
5
in the motor or the
machine.
Acceleration/
deceleration time is
6
different from the
setting.
Machine movement is
7
unstable.
Rotation ripple occurs
8 during the low-speed
operation.
Parameters referred to ???????
Pr.3 Base frequency, Pr.19 Base frequency voltage
Pr.72 PWM frequency selection
Pr.80 Motor capacity, Pr.81 Number of motor poles
Pr.125 Terminal 2 frequency setting gain frequency, Pr.126 Terminal 4 frequency setting gain frequency
Pr.359 Encoder rotation direction, Pr.369 Number of encoder pulses, Pr.851 Control terminal option-Number of encoder pulses, Pr.852 Control terminal
option-Encoder rotation direction
Pr.822 Speed setting filter 1
Pr.824 Torque control P gain 1 (current loop proportional gain)
172
PARAMETERS
Cause
Speed control gain is too
high.
Torque control gain is too
high.
Motor wiring is incorrect.
Torque shortage.
Load inertia is too high.
Speed control gain is not
suitable for the machine.
Response is slow because
of the inverter's
acceleration/deceleration
time setting.
High carrier frequency is
affecting the motor rotation.
Speed control gain is too
low.
page 591
page 261
page 137
page 64
page 400
Countermeasure
• Perform easy gain tuning.
• Set Pr.820 lower and Pr.821 higher.
• Perform speed feed forward control or model adaptive speed control.
• Set Pr.824 Torque control P gain 1 (current loop proportional gain)
lower.
• Check the wiring.
• Raise the torque limit.
(Refer to the torque limit for speed control on
• Perform speed feed forward control.
• Set acceleration/deceleration time suitable for the load.
• Perform easy gain tuning.
• Adjust Pr.820 and Pr.821.
• Perform speed feed forward control or model adaptive speed control.
• Set the optimum acceleration/deceleration time.
• Set Pr.72 lower.
• Set Pr.820 higher.
page 201
page 154.)
page 402