6-1 Sensorless Vector Control
The rotation speed of an induction motor, by its characteristic, decreases as the output torque increases.
Selecting sensorless vector control improves this relationship between the output torque and the rota-
tion speed of an induction motor, which results in a high output torque even at low speeds.
With sensorless vector control enabled, this inverter can output a high starting torque, 200% of the
motor rating, at 0.5Hz.
Moreover, this inverter also has a built-in auto-tuning function (rotation/stop method) that automatically
sets motor parameters.
6-1-1 Sensorless Vector Control Parameter Settings
•
Set the 1st/2nd Control Method (A044/A244) to 03 (Sensorless vector control).
•
Set the 1st/2nd Motor Capacity (H003/H203) and the 1st/2nd Motor Pole Number (H004/H204)
according to your motor.
•
Set the rated frequency of the motor in the 1st/2nd Base Frequency (A003/A203) and set the rated
voltage of the motor in the 1st/2nd Motor Rated Voltage Selection (A082/A282).
•
To use this function, set motor parameters for your motor according to 6-1-2 Offline Auto-tuning for
Motor Parameters on page 6-4 and 6-1-3 Motor Parameter Settings on page 6-9.
•
In the light load mode and the PM motor mode, sensorless vector control cannot be selected.
*1. To enable the switching to the 2nd control, allocate one of the Multi-function Input S8 Selection (C008) to 08
(SET) and turn ON that terminal.
Precautions for Correct Use
•
The inverter may not provide sufficient performance characteristics due to the current accu-
racy if your motor is two or more sizes lower than its maximum applicable motor capacity.
•
The motor may rotate in reverse at low frequencies (a few Hz), depending on the current
accuracy.
In this case, use the Reverse Rotation Prevention Selection (b046) function or refer to 6-1-4
Adjustments for Sensorless Vector Control on page 6-10 to adjust the motor parameter set-
tings.
•
If the incoming voltage to the inverter is higher than the rated voltage of the drive motor, set-
ting the 1st/2nd AVR Selection (A081/A281) to 01 (Always OFF) or 02 (OFF during decelera-
tion) may prevent normal operation as the current increases. In this case, set the 1st/2nd
AVR Selection to 00 (Always ON).
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