I am designing a closed loop pi control booster converter. when I want to automatically tune my discrete pi controller its show below message:

The plant model in the PID loop linearizes to zero, and therefore cannot be used in PID controller design. This problem occurs when one or more blocks in the PID loop have zero gain or the feedback loop is not physically closed. Click "Continue" to launch the PID Tuner and obtain a new plant model in the "Obtain plant model" dialog. Click "Cancel" to abort PID design and return to the block dialog. For more information, see the Simulink Control Design documentation.

Answer 1

[Arkadiy Turevskiy]

Yes, this often happens with SimPowerSystems models that have strong discontinuities that cannot be linearized using exact linearization.

See this section of the doc for suggestions.

This example should also be relevant.

Answer 2

[Arkadiy Turevskiy]

We just shipped new functionality in 14a to specifically address this scenario. Take a look here: PID Controller Tuning for a Model with Discontinuities.