Tuning The Drive Closed Loop Controller; Manual Pi Adjustment - Danfoss FC 101 Design Manual

Product Overview

2.7.9 Tuning the Drive Closed Loop Controller

Once the frequency converter's closed loop controller has been set up, the performance of the controller should be tested.
In many cases, its performance may be acceptable using the default values of 20-93 PI Proportional Gain and 20-94 PI Integral
Time. However, in some cases it may be helpful to optimize these parameter values to provide faster system response while
still controlling speed overshoot.

2.7.10 Manual PI Adjustment

1. Start the motor.
2. Set 20-93 PI Proportional Gain to 0.3 and increase it until the feedback signal begins to oscillate. If necessary, start
and stop the frequency converter or make step changes in the set-point reference to attempt to cause oscillation.
Next reduce the PI proportional gain until the feedback signal stabilises. Then reduce the proportional gain by
40-60%.
3. Set 20-94 PI Integral Time to 20 s and reduce it until the feedback signal begins to oscillate. If necessary, start and
stop the frequency converter or make step changes in the set-point reference to attempt to cause oscillation. Next,
increase the PI integral time until the feedback signal stabilises. Then increase of the integral time by 15-50%.
®
VLT HVAC Basic Drive FC 101 Design Guide
MG18C502 - Rev. 2013-09-06
2 2
31