Siemens SINAMICS G150, Operating Instructions Manual

Page: 466 / 680

Setpoint channel and closed-loop control
7.4 Vector speed/torque control with/without encoder
Converter cabinet units
466
Operating Instructions, 07/2016, A5E03347396A
7.4.9 Permanent-magnet synchronous motors
Description
Permanent-magnet synchronous motors without encoders are supported during operations
without encoders.
Typical applications include direct drives with torque motors which are characterized by high
torque at low speeds, e.g. Siemens complete torque motors of the 1FW3 series. When these
drives are deployed, gear units and mechanical parts subject to wear can be dispensed with
if the application allows this.
WARNING
Danger to life as a result of electric shock when permanent magnet synchronous motors
rotate
As soon as the motor rotates, a voltage is generated at the terminals, which when touched,
can result in death or severe injury.
•
Electrically disconnect the motor when working on the converter.
•
If it is not possible to disconnect the connecting cables to the motor, secure the motor so
that it cannot undesirably rotate, e.g. using a holding brake.
Features
● Field weakening of up to approx. 1.2 x rated speed (depending on the supply voltage of
the converter and motor data, also see supplementary conditions)
● Flying restart (during operation without encoders, only when a VSM records the motor
speed and phase angle (option K51))
● Speed and torque control vector
● V/f control for diagnostics vector
● Motor identification
● Speed controller optimization (rotary measurement)
Supplementary conditions
● Maximum speed or maximum torque depend on the converter output voltage available
and the back EMF of the motor (calculation specifications:
EMF must not exceed V
rated, converter
).
● Calculating the maximum speed:
● Depending on the terminal voltage and load cycle, the maximum torque can be taken
from the motor data sheets / configuration instructions.
● No thermal model is available for the closed-loop control of a permanent-magnet
synchronous motor. The motor can only be protected against overheating by using
temperature sensors (PTC, KTY). To achieve a high level of torque accuracy, we
recommend a temperature sensor (KTY) to measure the motor temperature.