Etel DSC Series User Manual

ETEL Doc. - Operation & Software Manual # DSC2P 903 / Ver. F / 3/6/05 Chapter C: System functions
Operation & Software Manual
Direct Drives & Systems 139
The integrator's effect (parameter K4) may also be disabled with parameter K7.
13.1.2.2 Current regulator's gains
The current reference generator, with the motor look-up table, calculates the input current into each motor
phase from the reference force F
c
delivered by the position loop and the real motor position. The current loop
itself makes sure that this reference is reached.
To do that, a classical PI regulator is used. Parameter K80 is proportional to the force reference F
c
. It is used
to make the current regulator more reactive. The integral gain given by parameter K81 will reduce oscillations
and suppress a permanent error on the current (and on the force).
Parameter K23 is the phase advance. The current in the motor should always be in phase with the B-EMF; in
normal cases, the motor look-up table guarantees it. Nevertheless, when a motor moves at high speed (>2m/
s) the current tends to be late with respect to the B-EMF. This delay can be compensated with a positive phase
shift of the pointers in the motor look-up table (as the motor currents are late, one has to point ahead in the
look-up table). Parameter K23 corresponds to the phase shift defined for the pointers.
The formula below gives the value of parameter K23 according to the requested phase shift expressed in
degrees, and the motor speed:
Monitoring M11 is the motor real speed. The application nominal speed will be chosen.
Remark: With a direct drive, the quality of the current loop has to be very good, otherwise the noise due to
the transistor commutation or the current bad measurement due to a ripple, will not be removed
with the position loop. A special algorithm has been developed in the controller to reduce the
noise.
13.1.2.3 Regulators filters
Numeric filters have been integrated in the regulators. They are set with parameters K9 and K82 in the current
regulator and parameter K8 in the position regulator. These are low-pass and first order filters.
The same type of formula is valid to calculate cut off frequencies f
c
at –3dB for parameters K8, K9 and K82:
K Name Value Comment
K7 Integrator mode
0
2
Integrator gain (parameter K4) always on
Integrator gain (parameter K4) always off
Available on DSC2P DSC2V DSCDP DSCDL DSCDM
K Name Comment
K23
Commutation phase
advance versus speed
Advance of phase commutation versus speed
K80 Current loop proportional gain Proportional gain of the current loop.
K81 Current loop integrator gain Integrator gain of the current loop.
Available on DSC2P DSC2V DSCDP DSCDL DSCDM
K23
2
30
Phase shift [degrees]×
360 M11×
-------------------------------------------------------------
=
fc
10
2Π SamplingTime Gain⋅⋅
--------------------------------------------------------------------
= Hz[]

Etel DSC Series Specifications

General

Brand	Etel
Model	DSC Series
Category	Controller
Language	English