FC 300 Design GuideIntroduction to FC 300" Speed PID ControlThe table shows the control configurations where the Speed Control is active. To see where theSpeed Control is active, please refer to the section about the Control Structure.Par. 1-01 Motor Control PrinciplePar. 1-00Configuration Mode U/f VVCplus Flux sensorless Flux w motor feedb[0] Speed open loop Not Active Not Active ACTIVE N.A.[1] Speedclosed-loopN.A. ACTIVE N.A. ACTIVE[2] Torque N.A. N.A. N.A. Not Active[3] Processopen-loopN.A. Not Active ACTIVE ACTIVENote: "N.A." means that the specific mode is not available at all. "Not Active" means that thespecific mode is available but the Speed Control is not active in that mode.Note: The Speed Control PID will work under the default parameter setting, but tuning the parametersis highly recommended to optimize the motor control performance. The two Flux motor controlprinciples are specially dependent on proper tuning to yield their full potential.The following parameters are relevant for the Speed Control:Parameter Description of functionSpeed PID Feedback ResourcePar. 7-00Select from which resource (i.e. analog or pulse input) the Speed PID should getits feedbackSpeed PID Proportional GainPar. 7-02The higher the value, the quicker the control. However, too high a value maylead to oscillations.Speed PID Integral Time Par.7-03Eliminates steady state speed error. Lower value means quick reaction. However,too low a value may lead to oscillations.Speed PID Differentiation TimePar. 7-04Provides a gain proportional to the rate of change of the feedback. A setting ofzero disables the differentiator.Speed PID Diff. Gain Limit Par.7-05If there are quick changes in reference or feedback in a given application - whichmeans that the error changes swiftly - the differentiator may soon become toodominant. This is because it reacts to changes in the error. The quicker the errorchanges, the stronger the differentiator gain is. The differentiator gain can thus belimited to allow setting of the reasonable differentiation time for slow changes anda suitably quick gain for quick changes.Speed PID Lowpass Filter TimePar. 7-06A low-pass filter that dampens oscillations on the feedback signal and improvessteady state performance. However, too large a filter time will deteriorate thedynamic performance of the Speed PID control.33MG.33.B3.22 - VLT is a registered Danfoss trademark
