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Engineering Guide CDA3000
3 Selection of inverter module
Field-Oriented Regulation (FOR)
In FOR the rotor and speed positions are ascertained with an encoder.
Based on those measurement variables, the flux- and torque-forming cur-
rents can always be fed into the motor in optimum positions relative to
each other. This produces maximum dynamics and smoothness.
General characteristics of the
motor control methods
VFC
Voltage
Frequency
Control
SFC
Sensorless
Flux
Control
FOR
Field-Oriented
Regulation
Torque rise time approx. 10 ms <2 ms < 2ms
Dynamic disturbance correction NO YES YES
Standstill torque NO NO YES
Correction time for a load surge
of 1 x M
N
<100 ms <100 ms <100 ms
Anti-stall protection limited YES YES
Speed manipulating range M
Const.
1:20 1:50 >1:10000
Static speed accuracy n/ n
N
<2% <1% quartz-accurate
Frequency resolution 0.01 Hz 0.0625 Hz
2
-16
Hz
Motor principle
asynchronous
synchronous
reluctance
asynchronous asynchronous
Multi-motor operation yes no no
Encoder evaluation no no yes
Table 3.31 Efficiency of the motor control methods with standard three-
phase AC motor
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