gefran BDI50-3055-KBX-4-NP-F - Page 122

4-75
11 Performance control functions
11- 00
Prevention of Reverse operation
Range
【
0
】
:Reverse command is enabled
【
1
】
:Reverse command is disabled
 11-00=1, the reverse command is disabled.
11- 01
Carrier Frequency
Range
【
1~16
】
KHz
11- 02
Carrier mode selection
Range
【
0
】
: Mode 0 3-phase PWM modulation
【
1
】
: Mode 1 2-phase PWM modulation
【
2
】
: Mode 2 random PWM modulation
The function can be used for audible noise reduction from a motor. It can be used in cases where
the 100% torque from motor is not critical but it is necessary to reduce the audible noise.
 Mode 0: 3-phase PWM Modulation. Three Output transistors are ON at the same time (Full
Duty). Carrier frequency is set according to Parameter 11-01.
 Mode 1: 2-phase PWM Modulation. Two output transistors are ON at the same time (2/3 Duty).
This mode is suitable for variable torque applications such as Fan & pump. It reduces the
Output transistor switching losses.
Carrier frequency will be according to parameter 11-01 with the exception noted below:
Note:
If 11-01 > 2KHz, 11-03=0 (Auto carrier frequency change is disabled) and the following
conditions apply then 2-phase PWM will automatically change to 3- phase PWM with the carrier
frequency = 2/3* (11-01).
Conditions:
• During Acceleration If Output frequency is < 0.7*Fmax.
• During Deceleration when output frequency is < 0.6*Fmax
• Fmax = (Par 01-02) in Control mode (Par 00-00) = (0) V/f mode
• Fmax = (Par 02-06) in Control mode (Par 00-00) = (1) SLV mode
 Mode 2: Random PWM Modulation
This modulation method will use 3-phase PWM and 2-phase PWM modulation in a random
combination. Carrier frequency is set according to Parameter 11-01.
PWM mode selection considerations:
Modes Name IGBT Duty
Heat
Losses
Torque
Performance
Waveform
Distortion
Motor
Noise
0
3-Phase PWM
100%
High
High
Low
Low
1
2-Phase PWM
66.6%
Low
Low
High
High
2
Random PWM
66.6%
Low
Low
High
Mid