P86 High-performance speed controller structure

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1

Hello,
does anybody know the physical interpretation of P86 inverter parameters: FreqLoop Stab (STA) and FreqLoop Gain (FLG)?
These parameters are part of the speed loop optimization settings. While the parameters of a standard speed controller are perfectly clear (a classical IP controller, or in other words, a pseudo-derivative feedback controller), the high-performance speed controller parameters STA and FLG are not easily understandable to me. In fact, the variable names are explicit enough, but the underlying controller structure is unclear.
Regards
Michal Malek

2

Hello,

The FreqLoop Gain (FLG) and FreqLoop Stab (STA) parameters in the P86 inverter are part of the speed loop tuning process in high-performance mode. Here’s a simplified breakdown:

  • FreqLoop Gain (FLG): This controls how aggressively the speed loop reacts to changes, such as load variations or speed setpoint adjustments. Increasing FLG makes the system respond faster, but if it’s set too high, it might cause oscillations or instability.

  • FreqLoop Stab (STA): This helps stabilize the speed loop, especially after disturbances. It acts as a damping factor, ensuring the system doesn’t overshoot or oscillate when returning to a steady speed.

Both parameters work together: FLG focuses on responsiveness, while STA ensures stability. To tune them, you typically start with moderate values for both, then increase FLG for quicker responses and adjust STA as needed to eliminate oscillations.

These settings are particularly useful for applications where precise speed control is critical, especially in systems with varying load conditions.

Hope this helps clarify their role!

For specific support i recommend to contact the B&R support channel.

Best regards,
Josef

3

Hello Josef,
Thank you for the comprehensive explanation. Perhaps my question wasn’t clear. As I mentioned, I have a general understanding of what those parameters are about, but the difference between the standard controller and high-performance controller structures is still unclear. This is because response and stability can be fully controlled with the standard controller parameters as well. Performance can be enhanced by using a feedforward path. Another way to phrase my question is whether the FLG and STA could improve behavior compared to the standard controller parameters.

However, you are right that these types of questions should probably be addressed directly to Schneider Electric.

Best regards,
Michal Malek