7.3.7 Torque control with defined bandwidth
The controller gain is determined by activating test signals (Autotuning). The
calculations and the relevant autotuning are carried out in the servo drive. The
advanced settings are made in P 1530[0] - SCD_SetMotorControl, P 1531[0] -
SCD_Action_Sel and P 1533[0] - SCD_AT_Bandwidth.
l
The 3dB bandwidth of the closed loop is specified as the bandwidth.
l
Advisable bandwidth settings at 8 kHz switching frequency are up to
approximately 2000 Hz; at 16 kHz switching frequency up to approximately
3000 Hz.
l
The P-gain CCON_Kp is calculated according to the amount optimum.
l
The integral-action time CCON_Tn is interpolated between the amount
optimum and the symmetrical optimum, so that the I-content is sufficient,
resulting in reduced interference response.
P no.
Index Name / Setting
Unit Function
1530
0
SCD_SetMotorControl
Torque controller setting with defined bandwidth
Fault(-1)
Error during calculation
Ready(0)
Calculation ready
CALC_CON(1)
Control with motor data calculation
CALC_ASM(2)
Calculate asm motor from rated data
BANDWIDTH(3)
Calculate current controller by bandwidth
DEADBEAT(4)
This setting parameterizes a dead-beat
controller. The structure is switched to
feedback with observer, the observer is
designed (to a specific equivalent time constant
– for setting see
P 434[0] - CON_CCON_
ObsPara
– and the speed controller gains are
calculated accordingly.
1531
0
SCD_Action_Sel
Start conditions to determine the torque
controller settings
FAULT (-1)
Selected function stopped with fault
READY (0)
Ready to start function / last call successfully
ended
Table 7.10: “Torque control with defined bandwidth” parameters
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
129
7 Control
P no.
Index Name / Setting
Unit Function
ENC_OFFSET (1)
Start encoder offset determination (power stage
will be switched on!)
MOT_ID (2)
Start electrical motor identification (power stage
will be switched on!)
IMP (3)
Measure impedance
LH_TUNE (4)
Tune Lm characteristics
ASM_OP (5)
Set operation point for asynchronous motor
BANDWIDTH (6)
Tune current controller by bandwidth
MOTPHASE (7)
Check motor/encoder wiring
COM_ALL (8)
Motorid., enc.-offset and inertia detection,
motor phase check
J_SUM (9)
Identification of whole inertia
CANCEL (10)
Cancel the current action
1533
0
SCD_AT_Bandwidth
Hz
Bandwidth preset for torque control loop:
Range: 10 - 4000 Hz
Table 7.10: “Torque control with defined bandwidth” parameters (continue)
7.3.8 Enhanced feed forward control of voltage
For high-power applications, the current control setting is often limited. If, at the same
time, a high bandwidth is required for the control of test signals, for example, feed-
forward voltage control is helpful.
ID
Index Name
Unit Description
434
CON_CCON_Para
Current observer parameters
434
0
TF
ms
Current observer time constant
434
1
Kp
1/s
Current observer feedback gain
434
2
Tn
ms
Current observer feedback time constant
Table 7.11: Parameter - Enhanced feed forward control