ASFIFF12 High Speed
vacon • 57
24-hour s358 (0)40 837 1150 • Email: [email protected]
3
6. APPENDICES
In this chapter you will find additional information on special parameter groups. Such groups are:
Closed Loop parameters (Chapter 6.1)
Advanced Open Loop parameters (Chapter 6.2)
Parameters of Motor thermal protection (Chapter 6.3)
Parameters of Stall protection (Chapter 6.4)
Parameters of Underload protection (Chapter 6.5)
Fieldbus control parameters (Chapter 6.6)
6.1
Closed loop parameters (ID’s 612 to 621)
Note:
It is not possible to run >320Hz in Close Loop.
Select the Closed loop control mode by setting value
3
or
4
.
Closed loop control mode (see page 37) is used when enhanced performance near zero speed and
better static speed accuracy with higher speeds are needed. Closed loop control mode is based on
"rotor flux oriented current vector control". With this controlling principle, the phase currents are
divided into a torque producing current portion and a magnetizing current portion. Thus, the squirrel
cage induction machine can be controlled in a fashion of a separately excited DC motor.
Note:
These parameters can be used with Vacon NXP drive only.
EXAMPLE:
Motor Control Mode = 3 (Closed loop speed control)
This is the usual operation mode when fast response times, high accuracy or controlled run
at zero frequencies are needed. Encoder board should be connected to slot C of the
control unit. Set the encoder P/R-parameter (P7.3.1.1). Run in open loop and check the
encoder speed and direction (V7.3.2.2). Change the direction parameter (P7.3.1.2) or
switch the phases of motor cables if necessary. Do not run if encoder speed is wrong.
Program the no-load current to parameter
and set parameter
(Slip Adjust) to
get the voltage slightly above the linear U/f-curve with the motor frequency at about 66% of
the nominal motor frequency. The Motor Nominal Speed parameter (
) is critical. The
) controls the available torque linearly in relative to motor
nominal current.
6.2
Advanced Open Loop parameters (ID's 622 to 625, 632, 635)
Select the Advanced Open Loop control mode by setting value
5
or
6
for parameter
The Advanced Open Loop control mode finds similar implementations as the Closed Loop control
mode above. However, the control accuracy of the Closed Loop control mode is higher than that of
the Advanced Open Loop control mode.
EXAMPLE:
Motor Control Mode = 5 Frequency control (Advanced open loop) and 6 Speed control
(Advanced open loop)
The motor is running at current vector control at low frequencies. At frequencies above the frequency
limit, the motor is in frequency control. The default current value is 120% at zero frequency. Use
linear U/f-curve (
). 120% starting torque should now be possible. Sometimes increasing the
) will improve the run. The Frequency limit is the critical point. Increase the
zero frequency point to get enough current at frequency limit.
