PROGRAMMING
SINUS K
MANUAL
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Besides forcing a torque compensation depending on operating frequency only, voltage may be increased (only
positive) based on the actual motor stress, i.e. based on the motor torque. This compensation (AutoBoost) is obtained
as follows:
∆
V= C09 x (C18/100) x (T / Tn)
where T is the expected motor torque and Tn is the motor rated torque.
Tn is calculated as follows:
Tn = [(Pn – Rs x I
2
) x pole pairs] / 2
π
f =
= [(C75 – C78 x M06
2
) x C74 / 2] / (2
π
x C06)
NOTE
AutoBoost compensation is active only when selecting the first voltage/frequency pattern.
Programmable parameters for the AutoBoost function are:
C18 (AutoBoost): variable torque compensation expressed as a percentage of the motor rated voltage (C09). The value
set for C18 represents the voltage increment when the motor runs with the rated torque.
C74 (poles).
C75 (Pn): Rated power of the connected motor.
C78 (Rs): Stator resistance of the connected motor.
3.2.
CARRIER FREQUENCY (IFD SW only)
Carrier frequency may be programmed based on output frequency as shown in Fig. 8. Adjust parameters in the
“Carrier Freq” submenu (Configuration menu):
C01
MIN CARRIER:
Minimum value of PWM modulation frequency
C02
MAX CARRIER:
Maximum value of PWM modulation frequency
C03
PULSE NUMBER:
Number of output pulses produced when switching from the minimum value to the
maximum value.
C04 SILENT MODULATION: Electrical noise due to switching frequency is weakened and becomes similar to
mechanical noise
Factory setting is dependent on the inverter size, but is always C01 = C02, C03 = 24. Always do the following:
-
never exceed the maximum allowable carrier frequency (automatically actuated by the inverter)
-
do not set a low pulse number (10÷15) for asynchronous modulation
Note that:
-
asynchronous modulation occurs with constant carrier independently on output frequency
-
synchronous modulation occurs with constant pulse number
-
pulse number is equal to
frequency
output
equency
carrier fr