Vector Speed/Torque Control With/Without Encoder - Siemens SINAMICS G150 Operating Instructions Manual

Setpoint channel and closed-loop control

7.4 Vector speed/torque control with/without encoder

7.4 Vector speed/torque control with/without encoder
Description
Compared with V/f control, vector control offers the following benefits:
● Stability vis-à-vis load and setpoint changes
● Short rise times with setpoint changes (–> better command behavior)
● Short settling times with load changes (–> better disturbance characteristic)
● Acceleration and braking are possible with maximum adjustable torque
● Motor protection due to variable torque limitation in motor and regenerative mode
● Drive and braking torque controlled independently of the speed
● Maximum breakaway torque possible at speed 0
These benefits are available without speed feedback.
Vector control can be used with or without an encoder.
The following criteria indicate when an encoder is required:
● Maximum speed accuracy requirements
● Maximum dynamic response requirements
● Torque control is required in a control range greater than 1:10
● Allows a defined and/or variable torque for speeds below approx. 10% of the rated motor
● A speed controller is normally always required for applications in which an unknown
With regard to setpoint input, vector control is divided into:
● Speed control
● Torque/current control (in short: torque control)
384
– Better command behavior
– Shortest settling times when disturbances occur
frequency (p0310) to be maintained.
speed can represent a safety risk (where a load can be dropped, e.g. lifting gear,
elevators, etc).
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A