Lenze i55AE155F User Manual

8.2.5 Sensorless control for synchronous motors (SL-PSM)
The sensorless control for synchronous motors is based on a decoupled, separated control of
the torque-producing current and the current in eld direcon. In contrast to the servo con-
trol, the actual speed value and rotor posion are reconstructed via a motor model.
NOTICE
In case of this motor control type, an adjustable, constant current is injected in the lower
speed range. If this current is higher than the rated motor current, the motor may heat up in
the lower speed range. This eect increases if the motor is operated in the lower speed range
for a longer period of me.
Possible consequence: Destrucon of the motor by overheang
▶
Do not operate the motor for a longer period of me in the lower speed range.
▶
For detecng and monitoring the motor temperature, we recommend a temperature feed-
back via PTC thermistor or thermal contact. 4Motor temperature monitoring ^ 219
Precondions
The sensorless control for synchronous motors (SL-PSM) is possible up to a rated power of
maximally 22 kW.
Details
This motor control type is acvated by seng 0x2C00 (P300.00) = "Sensorless control (SL
PSM) [3]".
The motor model-based speed observer requires a rotang machine. Thus, as a maer of
principle, the operaonal performance of the sensorless control for synchronous motors is
divided into two ranges:
1.
Low speed range (|setpoint speed| < lower limit 0x2C11:001)
•
In the range of low speed, the speed of a synchronous motor cannot be observed. In
this "Low speed range", an open-loop controlled operaon takes place: For accelera-
on processes, the current set in 0x2C12:001 is injected and for processes without
acceleraon (for instance standsll or constant setpoint speed) the current set in
0x2C12:002 is injected.
2.
High speed range (|setpoint speed| > lower limit 0x2C11:001)
•
In this area, the rotor ux posion and the speed are reconstructed by means of an
observer. The control is executed in a eld-oriented way. Only the current required for
generang the necessary torque is injected.
Pole posion idencaon (PLI)
•
For controlling a permanent-magnet synchronous motor, the pole posion - the angle
between the motor phase U and the eld axis of the rotor - must be known.
•
In case of a drive at standsll, the inverter enable is directly followed by the "pole posion
idencaon (PLI)" which idenes the inial pole posion.
Flying restart circuit
•
From rmware version 4 onwards, a ying restart circuit for the synchronous motor up to
speeds lower than half the rated speed is supported.
•
If the ying restart circuit shall be used, set the start method "Flying restart circuit [2]" in
0x2838:001 (P203.01). More sengs are not required for the ying restart circuit at sen-
sorless control of a synchronous motor.
For a speed control with torque limitaon in operang mode 0x6060 (P301.00) = "MS: Veloc-
ity mode [-2]":
1.
Select the source in 0x2949:001 (P337.01) for the posive torque limit source and set it
accordingly.
2.
Select the source in 0x2949:002 (P337.02) for the negave torque limit source and set it
accordingly.
Motor control
Motor control selecon
Sensorless control for synchronous motors (SL-PSM)
178

Lenze i55AE155F Specifications

General

Brand	Lenze
Model	i55AE155F
Category	Inverter
Language	English