Siemens SINAMICS G220 - Encoderless Speed Control of a Synchronous Reluctance Motor from Standstill

• Encoderless induction motors
– Before switching on and before enabling the pulses, enter a speed setpoint>p1755.
– For speed setpoint = 0, and with the motor holding brake open, the load drops because
the induction motor rotates backwards with the slip frequency as a result of the pulling
load.
– Set the ramp-up and ramp-down times≤10s in the ramp-function generator.
– To avoid open-loop speed controlled operation, close the holding brake and at standstill,
switch the converter o󹪜.
– For safety reasons, in p1610 set an absolute current value that is high enough so that the
heaviest load that occurs can be held at the constant setpoint speed.
– If, in quick commissioning, you have selected the Dynamic Drive Control operating mode,
set p0502=1 (technological application: dynamic starting or reversing).
• Encoderless synchronous reluctance motors
– Use the test signal technique, this requires a license.
– Set p1750, bit 5=1.
With this setting, the motor exhibits the same response as for a motor with encoder.
• Encoderless synchronous motors
– For safety reasons, for pulling loads, we explicitly recommend that synchronous motors
with encoders are used instead of encoderless synchronous motors.
Presently, the test signal technique for encoderless synchronous motors is not available.
– When using encoderless synchronous motors, it is crucial that you observe the following
setting:
In p1610 set an absolute current value that is high enough so that the heaviest load that
occurs can be held at the constant setpoint speed.
14.10.5.9 Encoderless speed control of a synchronous reluctance motor from standstill
Overview
The "Encoderless speed control of the synchronous reluctance motor from standstill" function
increases the energy e󹪟ciency of a synchronous reluctance motor and extends the range of
applications.
• Speed controlled operation up to and including a speed of 0
• Starting with high load
• Acceleration with ramp-up times close to 0
• Encoderless torque control possible
Requirement
The "Encoderless speed control of the synchronous reluctance motor from standstill" function
requires the license for the "Motor Control Extended" software option.
Functions
14.10Closed-loop drive control
SINAMICS G220 converter
Operating Instructions, 04/2024, FW V6.2, A5E51781573B AB 517