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When the integral time is set to be 0 (P05.01=0, P05.05=0), there is no integral action and the speed loop
is a simple proportion regulator.
2. Setting of the proportional gain P and integral time I of the speed regulator (ASR)
Fig. 6-21 Diagram of relationship between the step response and PI parameters
Increasing the proportional gain P can accelerate the dynamic response of the system, but if the P value
is too large, it is easy to cause the oscillation of the system.
Decreasing the integral time I can accelerate the dynamic response of the system, but if the I value is too
small, it is easy to cause the overshoot and oscillation of the system.
Generally, it is better to adjust the proportional gain P first to increase the P value as larger as
possible while ensuring no oscillation to the system, and then adjust the integral time I to ensure that the
system has quick response features and small overshoot. The Fig. 6-22 shows the speed step response
curve while the values of P and I are selected properly (the speed response curve can be observed with
the analog output terminals AO1 and AO2, please refer to the parameters of Group P10)
．
Fig. 6-22 Step response with good dynamic performance
Note
If the PI parameter is not selected properly, the over-voltage fault may occur after the system is started to
reach the high speed quickly (if no external braking resistor or brake unit is connected). This is caused by the
energy feedback produced in the system regenerative braking while decelerating after the overshoot. It can
be avoided by adjusting the PI parameter.
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