Mitsubishi Electric FR-A720-0.4K Instruction Manual page 210

FR-A
700 Series
Instruction Manual Supplement
The FR-A700 series that has the SERIAL on page 24 or later are compatible with the following
specifications. Check the serial number printed on the rating plate of the inverter.
In the following sections,
1 PM sensorless vector control
Purpose
To perform IPM parameter initialization
To select the torque characteristic in a
low-speed range.
To adjust the gain for PM sensorless
vector control
Highly efficient motor control and highly accurate motor speed control can be performed by using the inverter with an
IPM (internal permanent magnet) motor, which is more efficient than an induction motor.
The motor speed is calculated based on the output voltage and current from the inverter. It does not require a speed
detector such as an encoder. The inverter drives the IPM motor with the least required current when a load is applied
in order to achieve the highest motor efficiency.
POINT
The following conditions must be met to perform PM sensorless vector control.
· For the motor model, IPM motor must be used.
· The motor capacity must be equal to or one rank lower than the inverter capacity.
· Single-motor operation (one motor run by one inverter) must be performed.
· The overall wiring length with the motor must be 100m or less. (When the wiring length exceeds 30m,
offline auto tuning must be performed.)
CAUTION
· The speed setting range for an MM-CF IPM motor is between 0 and 200Hz.
· The carrier frequency is limited during PM sensorless vector control. (Refer to page 16)
· Constant-speed operation cannot be performed in the low-speed range of 200r/min or less under current
synchronization operation. (Refer to page 14)
· During PM sensorless vector control, the RUN signal is output about 100ms after turning ON the start command (STF,
STR). The delay is due to the magnetic pole detection.
· During PM sensorless vector control, the automatic restart after instantaneous power failure function operates only
when an MM-CF IPM motor is connected. When a built-in brake or a regeneration unit is used, the frequency search
may not be available at 2200r/min or higher. The restart operation cannot be performed until the motor speed drops to
a frequency where the frequency search is available.
indicates the functions that are driven by PM sensorless vector control.
P M P M P M
IPM parameter initialization
Low-speed range torque
characteristics
Adjusting the speed control
gain
P M P M P M
s I P t
Parameters to be Set
Pr. 820, Pr. 821
1/24
Refer to Page
Pr. 998
Pr. 788
Chapter 4 of the
Instruction Manual
(Applied)
BCN-C22005-634
4
14