Process Pid Control - Danfoss FC 300 Design Manual

FC 300 Design Guide
Motor Power [kW]
Note: Par. 1-20 is the motor power in [kW] (i.e. enter '4' kW instead of '4000' W in the formula). A practical value for the Bandwith is
20 rad/s. Check the result of the par. 7-02
resolution feedback such as a SinCos feedback):
x
0.01
Par
. 7 − 02 =
MAXIMUM
Speed PID Lowpass Filter Time
A good start value for par. 7-06
Ripple of 3 % is acceptable. For incremental encoders the Encoder Resolution is found in either par. 5-70
Resolution (PPR)
on standard drive) or par. 17-11
Generally the practical maximum limit of par. 7-02
other factors in the application might limit the par. 7-02
To minimize the overshoot, par. 7-03
Speed PID Differentiation Time
Par. 7-04
increments of this setting.

3.4.3 Process PID Control

The Process PID Control can be used to control application parameters that can be measured by a sensor (i.e. pressure, temperature, flow) and be
affected by the connected motor through a pump, fan or otherwise.
The table shows the control configurations where the Process Control is possible. When a Flux Vector motor control principle is used, take care also to
tune the Speed Control PID parameters. Refer to the section about the Control Structure to see where the Speed Control is active.
par. 1-00 Configuration par. 1-01
Mode
U/f
[3] Process N.A.
Note: The Process Control PID will work under the default parameter setting, but tuning the parameters is highly recommended to optimise the application
control performance. The two Flux motor control principles are specially dependant on proper Speed Control PID tuning (prior to tuning the Process
Control PID) to yield their full potential.
Illustration 3.3: Process PID Control diagram
Speed PID Proportional Gain
x Encoder Resolution x Par
4 . 7 − 06
x
2 π
is 5 ms (lower encoder resolution calls for a higher filter value). Typically a Max Torque
(5V TTL on MCB102 Option).
Speed PID Proportional Gain
Speed PID Proportional Gain
Speed PID Integral Time
could be set to approx. 2.5 s (varies with the application).
should be set to 0 until everything else is tuned. If necessary finish the tuning by experimenting with small
Motor Control Principle
VVC plus
Process
MG.33.BC.02 - VLT ® is a registered Danfoss trademark
3 Introduction to AutomationDrive FC 300
calculation against the following formula (not required if you are using a high
x Max torque ripple
%
Term 32/33 Pulses per Revolution
is determined by the encoder resolution and the feedback filter time but
to a lower value.
Flux Sensorless
Process & Speed
(24V HTL
Flux w/ enc. feedb
Process & Speed
3
33