Motion Control - Siemens SINAMICS G130 Engineering Manual

Fundamental Principles and System Description
Engineering Information
On drives which require a very high degree of precision, especially at very low speeds down to zero speed, or drives
which demand an excellent dynamic response, the actual speed value n
(E) and then passed to the motor model and the speed controller. Drives without high requirements of precision
and/or dynamic response do not need a speed encoder. In this case the actual speed value n
by the motor model and used instead of the speed encoder signal (encoderless control).
The quality of the field-oriented control critically depends on precise knowledge of the position of the magnetic field in
the motor and thus on the quality of the motor model. Only with precise field orientation direct and independent
access to the magnetic field and the torque is possible. For this reason, the motor model must be precisely tuned to
the connected motor. This tuning is part of the drive commissioning process. The rating plate data of the motor must
be input first. The motor is then automatically identified by the converter itself (measurements when motor is at
standstill and when motor is rotating).
Two types of field-oriented control modes are available for SINAMICS converters:
Vector control
Vector control is available as drive object of vector type in the standard firmware of all the SINAMICS converters
described in this engineering manual (SINAMICS G130, G150, S120, S150). The following vector control modes can
be selected:
·
Speed control with and without encoder (only TTL / HTL incremental encoders may be used as encoders for
SINAMICS G130 / G150 converters)
·
Torque control with and without encoder (only TTL / HTL incremental encoders may be used as encoders
for SINAMICS G130 / G150 converters)
The advantages of vector control lie in its very high torque accuracy and its high dynamic response. Relatively high
complexity as well as significant sensitivity to parameter fluctuations, such as changes in resistance caused by
temperature rise, are the disadvantages of this control mode. To achieve particularly high accuracy over the entire
speed range, therefore, it is important that the motor identification process is performed properly, that the effects of
temperature rise are compensated by use of a KTY motor temperature sensor and that friction compensation based
on recording of the friction characteristic is provided if necessary.
The control characteristics, such as rise times, accuracy, ripple, etc., as a function of current controller cycle settings
and motor types used can be found in the sections on specific unit types.
Typical applications for vector control are speed-controlled asynchronous motor drives with very high speed and
torque stability in general machine engineering, such as those employed, for example, on paper-making machines,
winders, coilers and lifting gear. However, permanent-magnet synchronous motors and separately excited
synchronous motors can also be operated in vector control mode.
Servo control
Servo control is available as drive object of servo type in the standard firmware of all SINAMICS S120 units. The
following servo control modes can be selected:
·
Speed control with and without encoder
·
Torque control with encoder
·
Position control with encoder
The advantages of servo control lie in its outstandingly high dynamic response, especially in cases where it is
possible to parameterize very short current controller cycles of < 250 μs. Its disadvantage lies in its torque accuracy
which is lower than that provided by vector control.
The control characteristics, such as rise times, accuracy, ripple, etc., as a function of current controller cycle settings
and motor types used can be found in chapter "General Information about Built-in and Cabinet Units SINAMICS
S120".
Typical applications for servo control are drives with highly dynamic motion control, such as those used in machine
tools, clocked production machines and industrial robots.
SINAMICS Engineering Manual – November 2015
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Ó Siemens AG
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