User Manual V 1-4.XX User guide

Control Block Diagrams B-23
If Fdbk Filter Sel (parameter 65) is set to 4, then the output is passed
through a notch filter before being used by the torque limit. Notch
Filtr Freq (parameter 185) sets the center frequency for the 2 pole
notch filter, and Notch Filtr Q (parameter 186) sets the quality factor.
The following is an example of a notch filter.
Understanding the Current Limits
The current limit function uses a minimum and maximum selection
routine to select the upper and lower Iq limits. The upper Iq limit is
the lowest value when Pos Mtr Cur Lim (parameter 72), the NTC
limit, and the IT limit are compared. The lower Iq limit is the largest
value when Neg Mtr Cur Lim (parameter 73), the negative of the NTC
limit, and the negative of the IT limit are compared.
The motor current limits affect the level of the total stator current (Is).
To convert from stator current (Is) to torque current (Iq), the flux
current (Id) must be compensated for. This is done by subtracting
Flux Current (parameter 168) from the motor current limit using
vector math.
During flux braking, the Iq limit is reduced significantly to allow high
levels of Id current. A large Id current is required for flux braking to
occur.
Understanding the Monitor-Motor Status
The monitor-motor status parameters are available for you to view the
values of various power-related functions. Positive values indicate
motoring power, and negative values indicate regenerative power.
file:
Control
group:
Speed Feedback
Hz
gain
Notch Filtr Q
(parameter 185)
0 db
Notch Filtr Freq
(parameter 186)
Other filters are available through Fdbk Filter Sel. These filters are
covered in the Speed Feedback Overview section of this appendix.
file:
Control
group:
Control Limits