Flux Lowering Calculation - KEB COMBIVERT F5 MULTI Applications Manual

Functional Desription
DASM rated torque (dr.14)
max. torque (dr.15)
DASM max. torque at field weak
speed (dr.16)
DASM speed f. max. torque†(dr.17)
DASM field weak speed (dr.18)
Fig. 6.5.4.b Torque limitation
Max. torque (dr.15)
DASM max. torque at field
weakening speed (dr.16)
Torque limitation (CS.20...22)
6.6.5 Flux Lowering
Calculation
DASM field weakening speed
Flux adaption factor (dr.19)
Field weakening curve (dr.20)
Fig. 6.5.5 Flux lowering
Flux adaption factor
Chapter Section Page
6 6 8
The motor torque which has been calculated from the motor parameters is displayed
in dr.14. Parameter dr.15 indicates the maximum torque which is achieved in the
base speed range. It depends on the hardware current limitation - 5% and cannot
be altered.
Torque
Limiting line of motor torque
Available torque at the drive
DASM speed f. max.
In the base speed range the maximum torque is mainly limited by the hardware
current limits of the inverter. For a stable operation the control requires voltage
reserves in order to balance currents at any time, therefore the torque that can be
reached in the higher speed range is limited by the output voltage. The limit
characteristic is adjusted correctly when a voltage reserve of approx. 5Ö10 % of
the rated voltage is available at every operating point.
In this parameter the speed is adjusted at which the field weakening operation
starts.
(dr.18)
With the parameters dr.19, dr.20 the flux characteristic can be adapted to the
motor.
In this parameter the field weakening characteristic is adjusted. The value of 1
means that the flux is lowered after an 1/n function.
(dr.21)
Date Name: Basis
12.05.04 KEB COMBIVERT F5-M / S
Motor Data and Controller
DASM field weakening
speed (dr.18)
torque (dr.17)
1 2
Speed
Field weakening curve (dr.20)
dr.20 < 1
dr.20 = 1
dr.20 > 1
set value ( ru .1 ) + slip
field weakening speed (dr.18)
© KEB Antriebstechnik, 2002
All Rights reserved