Mitsubishi Electric FR-A820-00046 (0.4K), Instruction Manual

Page: 259 / 1218

Parameters Control method
FR-A800 5 - 57
PM sensorless vector control
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Highly efficient motor control and highly accurate motor speed control can be performed by using
the inverter with a PM (permanent magnet embedded) 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 PM motor with the least
required current when a load is applied in order to achieve the highest motor efficiency.
●
Performing the IPM parameter initialization makes the IPM motor MM-CF ready for the PM
sensorless vector control.
A magnetic field observer is a control method that calculates the motor speed/magnetic pole
position based on the motor voltage and current of a virtual motor which is set up in the inverter.
I002500E
Fig. 5-1: PM sensorless vector control image
NOTES The PM sensorless vector control requires the following conditions.
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The motor described in the table below is used.
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For the motor capacity, the rated motor current should be equal to or less than the inverter
rated current. (It must be 0.4 kW or higher.)
Using a motor with the rated current substantially lower than the inverter rated current will
cause torque ripples, etc. and degrade the speed and torque accuracies. As a reference, select
the motor with the rated motor current that is about 40% or higher of the inverter rated cur-
rent.
●
Single-motor operation (one motor to one inverter) is performed.
●
The overall wiring length with the motor is 100 m or less. (Refer to page 2-32.) (Even with the
IPM motor MM-CF, when the wiring length exceeds 30 m, perform offline auto tuning.)
●
A surge voltage suppression filter (FR-ASF/FR-BMF) or sine wave filter (MT-BSL/BSC) is not used.
Output
voltage
PM sensorless vector control image
Inverter
Speed
command
Controller
Inverter
circuit
Output
current
Magnetic field observer
Virtual motor
Speed/magnetic
pole position
Motor Condition
Mitsubishi IPM motor (MM-CF) Offline auto tuning is not required
IPM motor (other than MM-CF), SPM motor Offline auto tuning is required