Motor Noise, Noise Reduction; Pwm Carrier Frequency And Soft-Pwm Control - Mitsubishi Electric FR-A700 Instruction Manual

Parameter
6.19

Motor noise, noise reduction

6.19.1 PWM carrier frequency and Soft-PWM control (Pr. 72, Pr. 240, Pr. 260)
You can change the motor sound.
Pr.
Name
No.
PWM frequency
72
selection
Soft-PWM operation
240
selection
PWM frequency
260
automatic
switchover
The above parameters allow its setting to be changed during operation in any operation
mode even if "0" (initial value) is set in Pr. 77 "Parameter write selection".
Reading and writing are enabled when "0 (SLD) or 1 (LD)" is set in Pr. 570.
PWM carrier frequency changing (Pr. 72)
You can change the PWM carrier frequency of the inverter.
Changing the PWM carrier frequency produces an effect on avoiding the resonance frequency
of a mechanical system or motor or on reducing noise or leakage current generated from the
inverter.
Carrier frequencies under real sensorless vector control or vector control are as shown below.
Tab. 6-101: Carrier frequencies under real sensorless vector control or vector control
When using an option sine wave filter (MT-BSL/BSC) for the 02160 or more, set "25" in Pr. 72
(2.5kHz).
NOTE
When "25" (available with the 02160 or more) is set in Pr. 72, V/f control is forcibly selected.
FR-A700 EC
Initial
Setting Range Description
Value
01800 0–15 PWM carrier frequency can be
changed. The setting displayed is in
or (integral
[kHz]. The settings indicate the fol-
less value)
lowing frequencies:
2 0 ........................0.7kHz
02160
Settings between 1–14 correspond
or 0–6/25
directly to the frequency values.
more
15 ....................14.5kHz
25 ..................... 2.5kHz
0 Soft-PWM is invalid
1
When Pr. 72 = 0 to 5 (0 to 4 for
1
01800 or more), Soft-PWM is valid.
PWM carrier frequency is constant
independently of load. When the
carrier frequency is set to 3kHz or
0
more (Pr. 72 ≥ 3), perform continu-
1
ous operation at less than 85% of
the rated inverter current.
Decreases PWM carrier frequency
1
automatically when load increases.
Pr. 72
01800 or less
0 to 5
6 to 9
10 to 3
14/15
Parameters referred to
02160 or more
0 to 5
6
—
—
Motor noise, noise reduction
Refer to
Section
156 Stall prevention 6.7.4
operation selection
570 Multiple rating set- 6.7.5
ting
Carrier Frequencies (kHz)
2
6
10
14
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