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Siemens D 15.1 · 2017
Engineering Information
Control overview
5
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Mode of operation
Control features
The following table provides a summary of the performance
offered by the SINAMICS PERFECT HARMONY GH180 drives
with NXGpro control.
Overview of control features
Drive input protection
SINAMICS PERFECT HARMONY GH180 drives utilize software
functions to detect abnormal conditions due to internal drive
faults and thus protect the drive. You will find a description below
of some routines that are implemented in the NXGpro control for
drive protection.
Drive faults can be categorized into two types – "low impedance"
(with high current) and "high impedance" (with low current)
faults. A "low impedance" fault in the drive or the secondary side
of the transformer would result in a significant reactive current on
the primary side. The "one cycle protection" (or detection of
excessive input reactive current) is implemented to detect such
types of faults. A "high impedance" fault in the drive would result
in low current that is difficult to detect on the primary side of the
transformer but will result in measurable losses that can be used
to detect the condition. The "excessive drive losses protection"
allows faults such as these to be detected.
The current level identified by these functions cannot be easily
detected and may be insufficient to activate the main primary
protection. As a consequence, the fault signals issued by these
routines should be used with suitable interlocking, e.g., via a
relay output and/or serial communication, to disconnect the
medium voltage at the drive input.
One cycle protection
(or detection of an excessive input reactive current)
NXGpro control utilizes the reactive component of the drive input
current to determine whether a "low impedance" fault on the
secondary side of the transformer has occurred. For example, a
short-circuit in one of the secondary windings will result in poor
power factor on the high-voltage side of the transformer. A soft-
ware model of the transformer, based on the power factor at
rated load (typically 0.95), is implemented in the control proces-
sor. The drive input reactive current is continuously checked with
the predicted value from the model. An alarm trip is generated if
the actual reactive current exceeds the prediction by more than
10 %. This check is avoided during the first 0.25 seconds after
medium voltage power-up to avoid the inrush current from
causing nuisance trips.
Feature
Description
Output frequency
0 ... 300 Hz
1)
; for frequencies < 10 Hz and > 167 Hz, current derating is required.
Modulation
Multi-level PWM
Ride-through
• Medium-voltage ride-through:
> 5 cycles
• Control power ride-through with UPS:
> 5 cycles
Rotating motor
• Instantaneous mode: allows fast bypass
• Frequency scan mode: performed after residual motor voltage has collapsed
Induction motor control
• V/f control
• Vector control for induction motors without encoder
• Vector control for induction motors
Synchronous motor control
• Vector control for synchronous motors without encoder
• Vector control for synchronous motors
• Control of permanent-magnet motors
• Control of brushless synchronous motors with exciter
Emergency Stop category
Emergency Stop category 0 is set as standard for an uncontrolled shutdown.
The function includes voltage disconnection of the drive output by opening the circuit breaker.
Consequently the motor coasts down.
Energy-saving operation
Set using one parameter (for induction motors only)
Braking
Inverse speed (max. braking torque is approx. 0.25 % at full speed)
Auto tuning
Available for induction motors as long as the drive rated power exceeds 67 % of the motor rated power.
Transparent cell bypass
(option U11)
500 ms downtime with redundant cells; without redundant cells, the downtime depends on the motor open
circuit time constant.
Synchronous transfer
(option L29)
Synchronous transfer available for induction and synchronous motors
2)
Minimum voltage boost
Not implemented; as an alternative, automatic resistance compensation is available.
Flux attenuation modeling
Not implemented; a simple (single parameter function) implementation is available.
Zero speed control
Not implemented
1)
Although 0 Hz can be produced by the drive, torque generation is limited
at low output frequencies.
2)
Synchronous transfer applications with synchronous motors would require
a PLC to manage the exciter control.
© Siemens AG 2017