NORD Drivesystems BU0505 - Manual (Page 96)

SK 54xE – Users Manual for Frequency Inverters
96 BU 0505 GB-1013
P330
Regulation PMSM
(Regulation PMSM)
S
0 ... 3
{ 1 }
Determination of the regulation of PMSM (Permanent Magnet Synchronous Motors) at speed
n<n
SWITHOVER
(See P331).
0 = Voltage controlled: With the first start of the machine, a voltage indicator is memorised
which ensures that the rotor of the machine is set to the rotor position "zero". This type of
starting position of the rotor can only be used if there is no counter-torque from the machine
(e.g. flywheel drive) at frequency "zero". If this condition is fulfilled, this method of
determining the position of the rotor is very precise (<1° electrical). In principle, this method
is not suitable for lifting equipment, as there is always a counter-torque.
For operation without encoders (in preparation), the following applies: Up to the switch over
frequency P331 the motor (with the nominal current memorised) is driven under voltage
control. Once the switch over frequency has been reached, the method of determining the
rotor position is switched over to the EMF method. If, taking hysteresis (P332) into account,
the frequency falls below the value in (P331), the frequency inverter switches back from the
EMF method to voltage controlled operation.
1 = Test signal method: The starting position of the rotor is determined with a test signal. This
method also functions at a standstill with the brake applied, however it requires a PMSM
with sufficient anisotropy between the inductivity of the d and q axes. The higher this
anisotropy is, the greater the precision of the method. By means of parameter (P212) the
voltage level of the test signal can be adjusted and with parameter (P213) the position of the
motor position control can be adjusted. For motors which are suitable for use with the test
signal method, a rotor position accuracy of 5°…10° electrical can be achieved (depending
on the motor and the anisotropy).
For operation without encoders (in preparation), the following applies: Until the switchover
frequency is reached, the rotor position is determined by means of the test signal method.
After this, with the setting "0" it is switched over to the EMF method.
2 = Value from universal encoder, "Value from universal encoder": With this method the
starting position of the rotor is determined from the absolute position of a universal encoder
(Hiperface, EnDat with Sin/Cos track, BISS with Sin/Cos track or SSI with Sin/Cos track)
The universal encoder type is set in parameter (P604).
For this position information to be unique it must be known (or determined) how this rotor
position relates to the absolute position of the universal encoder. This is performed via the
offset parameter (P334). Motors should be delivered either with a starting rotor position
"zero" or the starting rotor position must be marked on the motor.If this value is not
available, the offset value can also be determined with the settings "0" and"1" of parameter
(P330). For this the drive unit is started with the setting "0" or "1". After the first start the
offset value which has been determined is saved in parameter (P334).However, this value is
volatile, i.e. it is only saved in the RAM. In order to save it in the EEPROM, it must be briefly
changed and then set back to the determined value.
After this, fine tuning can be carried out with the motor idling. For this, the drive is operated
in closed loop mode (P300=1) at as high a speed as possible below the field weakening
point. From the starting point, the offset is gradually adjusted so that the value of the voltage
component U
d
(P723) is as close to zero as possible. For this, a balance between the
positive and negative direction of rotation must be sought.
Usually the value "zero" will not be completely achieved, as at higher speeds the drive is
subjected to a slight load due to the motor fan. The universal encoder should be located on
the motor shaft.
3 = Value from CANopen encoder, "Value from CANopen encoder": As for "2", however a
CANopen absolute encoder is used to determine the starting position of the rotor.
NOTE: If there is an incremental encoder with a "null track" on the motor shaft, the "null track" can
also be used to determine the position of the stator. The zero impulse is then used for
synchronisation of the rotor position.
The offset between the zero pulse and the
actual "zero" rotor position is set in parameter (P334) "Encoder offset". If the Sense cable
(+5V Sense and 0V Sense) is not connected, there is no synchronisation to the zero pulse.
Parameter (P330) must be set to "0" or "1". The value which needs to be set for parameter
(P334) must be determined experimentally or must be enclosed with the motor.
Pos : 166 /Anleit ungen/5. / 6. Parametrier ung [BU 0500 / BU 0200]/ Par ameter/ P300-P399/ Paramet er P331 – U mschaltfr equenz PM SM [SK 54xE] @ 0\ mod_1327677873447_388. doc x @ 8934 @ @ 1