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9.3 Notes in Driving PMSM
When driving a permanent magnet synchronous motor (PMSM), observe the following notes. Items
not covered in this section are the same as for induction motor (IM) drive.
Item Specifications
Drive by commercial
power
A PMSM cannot be driven by commercial power. Be sure to use an inverter.
A failure could occur.
Wiring
Be sure to match inverter's output terminals (U, V and W) with motor's input
terminals (U, V and W).
Control mode
When F42 = 11 (V/f control for PMSM drive)
At the start of driving the motor, the inverter flows current equivalent to 80%
of the motor rated current (P03) to pull in the magnetic pole position for
synchronization. After that. the inverter accelerates the motor to the reference
frequency.
No magnetic pole position detection function is provided.
No auto search for an idling PMSM and restart function are provided.
Depending upon the magnetic pole position, the motor may run in the reverse
direction slightly at the start of running.
Speed control range
The speed control range is from 10% to 100% of the base frequency (F04).
Set the reference frequency to 10% or more of the F04 data.
Starting torque 70% or more at 10% of the base frequency.
Motor constants
The following motor parameters are used, so consult the motor manufacturer
and configure the correct values. No tuning function is provided.
F04: Base frequency (Hz)
F05: Rated voltage at base frequency) (V)
(When F05 = 0, the inverter acts as 200/400V setting.)
P03: Motor rated current (A)
P60: Armature resistance (Ω)
P61: d-axis inductance (mH)
P62: q-axis inductance (mH)
P63: Induced voltage (V)
If any of P60, P62 and P63 is set to "0.00," the inverter does not start. Be sure
to set correct values. The factory defaults of P60 to P63 are "0.00."
If motor parameters are not correct, the inverter cannot run normally.
Set P90 to the value less than the demagnetizing current.
A failure could occur.
Carrier frequency
The carrier frequency (F26) should be 2 to 16 kHz. Running a PMSM at 0.75
or 1 kHz may result in a failure due to demagnetization. The automatic carrier
frequency lowering function at the time of inverter overheat does not work.
A failure could occur.
2nd motor A PMSM cannot be driven as the 2nd motor.
V/f pattern
Linear V/f pattern only.
The load selection value (F37) will be ignored.
Auto energy saving When driving a PMSM, the high-efficiency control is always ON.
Instantaneous
overcurrent limiter
This does not work for a PMSM.
The H12 setting will be ignored. Even if H12 = 1, an overcurrent trip occurs
due to an overcurrent incident.
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