Safety
information
Product
information
Mechanical
installation
Electrical
installation
Getting
started
Basic
parameters
Running the
motor
Optimization
NV Media Card
Operation
Building
Automation
Advanced
parameters
Technical
data
Diagnostics
UL listing
information
HVAC Drive H300 155
Issue Number: 3
Pr 00.024 {05.012} Autotune
There are two autotune tests available in RFC-A mode, a stationary test,and a rotating test. A stationary autotune will give moderate performance
whereas a rotating autotune will give improved performance as it measures the actual values of the motor parameters required by the drive.
It is highly recommended that a rotating autotune is performed (Pr 00.024 set to 2).
Autotune test 1:
• A stationary autotune can be used when the motor is loaded and it is not possible to remove the load from the motor shaft. The stationary
autotune measures the Stator Resistance (05.017) and Transient Inductance (05.024) of the motor. These are used to calculate the current loop
gains, and at the end of the test the values in Pr 04.013 and Pr 04.014 are updated. A stationary autotune does not measure the power factor of
the motor so the value on the motor nameplate must be entered into Pr 05.010. To perform a stationary autotune, set Pr 00.024 to 1, and
provide the drive with both an enable signal (on terminal 29) and a run signal (on terminal 24).
Autotune test 2:
• A rotating autotune should only be used if the motor is unloaded. A rotating autotune first performs a stationary autotune, a rotating test is then
performed in which the motor is accelerated with currently selected ramps up to a frequency of Rated Frequency (05.006) x 2/3, and the
frequency is maintained at the level for up to 40 s. During the rotating autotune the Stator Inductance (05.025) is modified by the drive. The
power factor is also modified for user information only, but is not used after this point as the stator inductance is used in the vector control
algorithm instead. To perform a Rotating autotune, set Pr 00.024 to 2, and provide the drive with both an enable signal (on terminal 29) and a
run signal (on terminal 24).
Following the completion of an autotune test the drive will go into the inhibit state. The drive must be placed into a controlled disable condition
before the drive can be made to run at the required reference. The drive can be put in to a controlled disable condition by removing the Safe Torque
Off signal from terminal 29, setting the Drive Enable (06.015) to OFF (0) or disabling the drive via the control word (Pr 06.042 & Pr 06.043)
Pr 04.013 / Pr 04.014 Current Loop Gains
The current loop gains proportional (Kp) and integral (Ki) gains control the response of the current loop to a change in current (torque) demand. The
default values give satisfactory operation with most motors. However, for optimal performance in dynamic applications it may be necessary to
change the gains to improve the performance. The Current Controller Kp Gain (04.013) is the most critical value in controlling the performance. The
values for the current loop gains can be calculated by performing a stationary or rotating autotune (see Autotune Pr 00.024 earlier in this table) the
drive measures the Stator Resistance (05.017) and Transient Inductance (05.024) of the motor and calculates the current loop gains.
This will give a step response with minimum overshoot after a step change of current reference. The proportional gain can be increased by a factor
of 1.5 giving a similar increase in bandwidth; however, this gives a step response with approximately 12.5 % overshoot. The equation for the integral
gain gives a conservative value. In some applications where it is necessary for the reference frame used by the drive to dynamically follow the flux
very closely (i.e. high speed Sensorless RFC-A induction motor applications) the integral gain may need to have a significantly higher value.
To Next Page
Loading...
