
C-2
Application Notes
Fixed Frequency Control Applications
Many of the applications require a fixed frequency operation with
variable voltage levels. For these applications it is best to set the
frequency ramp rates to “0” using [Accel Time 1 & 2] and [Decel Time 1
& 2], parameters 140-143. The ramp rates for output voltage are
independently controlled with parameters [Adj Volt AccTime] and [Adj
Volt DecTime], parameters 675-676.
Output Filters
Several adjustable voltage applications may require the use of output
filters. Any L-C or sine wave filter used on the output side of the drive
must be compatible with the desired frequency of operation, as well as
the PWM voltage waveform developed by the inverter. The drive is
capable of operating from 0-400 Hz output frequency and the PWM
frequencies range from 2-10 kHz. When a filter is used on the output of
the drive, [Drive OL Mode], parameter 150 should be programmed so
that PWM frequency is not affected by an overload condition (i.e. “0,
Disabled” or “1, Reduce CLim”).
Trim Function
The trim function can be used with the Adjustable Voltage mode. The
value of the selection in [Adj Volt TrimSel], parameter 669 is summed
with the value of [Adj Volt Select], parameter 651. Scaling of the trim
function is controlled with [Adj Volt Trim%], parameter 672. When the
sign of [Adj Volt Trim%] is negative, the value selected in [Adj Volt
TrimSel] is subtracted from the reference.
Process Control
The Process PI loop in the drive can be configured to regulate the
frequency or voltage commands of the drive. Typical applications using
the Adjustable Voltage mode will close the loop around the voltage
command. Process PI is enabled by selecting “1, AdjVoltTrim” in bit 10
of [PI Configuration], parameter 124. This bit configures the PI regulator
output to trim the voltage reference, rather than the torque or speed
references. The trim can be configured to be exclusive by selecting “1,
Excl Mode” in bit 0 of [PI Configuration], parameter 124. Trimming the
voltage reference is not compatible with trimming the torque reference,
thus if bits 10 and 8 of [PI Configuration] are set, a type II alarm will
occur, setting bit 19 (PI Cfg Cflct) in [Drive Alarm 2], parameter 212.
Содержание Allen-Bradley PowerFlex 700 B Series
Страница 1: ...Adjustable Frequency AC Drive Series B Firmware Versions 4 001 User Manual www abpowerflex com ...
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Страница 36: ...1 26 Installation Wiring Notes ...
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