58 Program features
The autophasing routine is performed with permanent magnet synchronous motors
and synchronous reluctance motors in the following cases:
1. One-time measurement of the rotor and encoder position difference when an
absolute encoder, a resolver, or an encoder with commutation signals is used
2. At every power-up when an incremental encoder is used
3. With open-loop motor control, repetitive measurement of the rotor position at
every start
4. When the position of the zero pulse must be measured before the first start after
power-up.
Note:
In closed-loop control, autophasing is performed automatically after the motor
identification run (ID run). Autophasing is also performed automatically before starting
when necessary.
In open-loop control, the zero angle of the rotor is determined before starting. In
closed-loop control, the actual angle of the rotor is determined with autophasing when
the sensor indicates zero angle. The offset of the angle must be determined because
the actual zero angles of the sensor and the rotor do not usually match. The
autophasing mode determines how this operation is done both in open-loop and
closed-loop control.
The rotor position offset used in motor control can also be given by the user – see
parameter
98.15
Position offset user
. Note that the autophasing routine also writes its
result into this parameter. The results are updated even if user settings are not
enabled by
98.01
User motor model mode
.
Note:
In open-loop control, the motor always turns when it is started as the shaft is
turned towards the remanence flux.
Bit 4 of
06.21
Drive status word 3
indicates if the rotor position has already been
determined.
Autophasing modes
The ACS380 uses turning mode (see parameter
21.13
Autophasing mode
).
The turning mode (
Turning
) is the most robust and accurate method. In turning mode,
the motor shaft is turned back and forward (±360/polepairs)° in order to determine the
rotor position. In case 3 (open-loop control), the shaft is turned only in one direction
and the angle is smaller.
The drive is capable of determining the rotor position when started into a running
motor in open-loop or closed-loop control. In this situation, the setting of
21.13
Autophasing mode
has no effect.
The autophasing routine can fail and therefore it is recommended to perform the
routine several times and check the value of parameter
98.15
Position offset user
.
ACS380 FW.book Page 58 Friday, May 4, 2018 4:18 PM
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