SSD 605C Product Manual - page 113
Programming Your Application
6-47
605C Frequency Inverter
PATTERN GEN
The pattern generator function block allows
the user to configure the Inverter PWM
(Pulse Width Modulator) operation.
Functional Description
The Inverter provides a unique quiet pattern PWM strategy in order to reduce audible motor
noise. The user is able to select between the quite pattern or the more conventional fixed carrier
frequency method. With the quiet pattern strategy selected (random pattern enabled), audible
motor noise is reduced to a dull hiss.
In addition, the user is able to select the PWM carrier frequency. This is the main switching
frequency of the power output stage of the Frequency Inverter. A high setting of carrier
frequency (e.g. 9kHz) reduces audible motor noise but only at the expense of higher Inverter
losses and smooth motor rotation at low output frequencies. A low setting of carrier frequency
(e.g. 3kHz), reduces Inverter losses but increases audible motor noise.
MMI Menu Map
1 SETUP PARAMETERS
2 FUNCTION BLOCKS
3 MOTOR CONTROL
4 PATTERN GEN
RANDOM PATTERN
PATTERN GEN FREQ
DEFLUX DELAY
DRIVE FREQUENCY
VOLTS
BOOST
PATTERN GEN
DRIVE FREQUENCY [591] – 0.0 Hz
VOLTS [592] – 0.0 V
BOOST [593] – 0.0 V
TRUE – [ 98]
RANDOM PATTERN
–
3 kHz – [ 99] FREQ SELECT
–
** 2.0 s – [100] DEFLUX DELAY
–
Parameter Descriptions
RANDOM PATTERN
Range: FALSE / TRUE
This parameter selects between random pattern (quiet motor noise) or the more conventional
fixed carrier PWM strategies. When TRUE, random pattern is enabled.
FREQ SELECT
Range: Enumerated - see below
This parameter selects the base switching frequency of the output power stack. The choices of
switching frequency are:
Enumerated Value : Frequency
0 : 3 kHz
1 : 6 kHz
2 : 9 kHz
The higher the switching frequency, the lower the level of motor audible noise. However, this is
only achieved at the expense of increased Inverter losses.
Note: This parameter is internally clamped to 3kHz on 0.75kW, 380/460V units.
DEFLUX DELAY
Range: 0.1 to 10.0 s
Sets the minimum allowed delay between disabling and then re-enabling PWM production (i.e.
stopping and starting the drive).
DRIVE FREQUENCY
Range: xxxx.x Hz
The Inverter output frequency.
VOLTS
Range: xxxx.x V
The Inverter output volts.
BOOST
Range: xxxx.x V
The Inverter output boost.