Beckhoff AX5000 Series Function Manual

Torque (Force) – Controller Structure
Function description 79
Version: 1.5
18.1.4 Current controller
The current controller represents the inner controller of the cascading control loop structure. Based on field-
oriented control, an advanced PI controller provides the current components required for the requested
operation mode S-0-0032. The q-current is proportional to the torque (for linear motors it is proportional to
the force). The settings for the current controller parameters K
p
and T
N
are based on the motor winding data
and the optimum bandwidth (compromise between dynamics and noise generation).
For Beckhoff motors the settings for the optimum bandwidth are taken from the electronic type plate (or
offline from the motor data files *.xeds). For the most applications these settings can be left unchanged. The
motor data generator can be used to create motor data files for third-party motors.
Corresponding pre-controls are applied to deal with systematic interference:
• Load and mains voltage-dependent fluctuations of the DC link voltage
• Induced motor voltage and
• Voltage over the winding inductance.
18.1.4.1 Generation of the output voltage
Generation of the output voltage for the AX5000 servo drive is based on a PWM clock frequency of 8 kHz. In
order to reach an acceptable compromise between power loss and requirements for the insulation system of
the motor, the AX5000 operates with a maximum rate of voltage rise (d
u
/ d
t
) of 5 kV per µs.
Note
IDN P-0-0001 (Switching frequency of the IGBT module)
Further information on the clock frequency of the AX5000 servo drive can be found in the
description of the IDN parameters (www.beckhoff.de
) under:
P-0-0001 (Switching frequency of the IGBT module).
The voltage profile at the servo drive output described above results in certain requirements for:
• the cable configuration,
• the cable length and
• the insulation system of the motor.
If Beckhoff cables and motors are used, all requirements are met, based on the procedures described in
chapter „Motors and cables for servo drives“.
Note
EMC-compliant commissioning
Further information on EMC-compliant commissioning can be found in the
AX5000 EMC leaflet, which is available on the Beckhoff website (www.beckhoff.de
).

Beckhoff AX5000 Series Specifications

General

Brand	Beckhoff
Model	AX5000 Series
Category	Servo Drives
Language	English