Configuring the Closed-Loop PID Autotuner Blocks
In this example, you improve the controller performance using Closed-Loop PID
Autotuner blocks. These blocks estimate the plant frequency response with the loop
closed during the experiment and then tune the controller gains. Examine the Control
subsystem to see the Closed-Loop PID Autotuner blocks in the Autotuning Speed and
Autotuning Voltage subsystems.
open_system([mdl '/Control']);
Following the typical cascade loop tuning practice, first tune the inner voltage loop with
the outer speed loop open. Then tune the outer speed loop with the inner voltage loop
closed.
To specify tuning requirements for the PID controllers, use the parameters in the
"Tuning" tab of each of the PID autotuner blocks. In this example, the controllers are
parallel, discrete-time, PI controllers. The controller sample time is 100 microseconds.
A Target Phase Margin of 60 degrees for both controllers gives a good balance between
performance and robustness.
For the outer speed loop control, choose a Target Bandwidth of 100 rad/sec. For the
inner voltage loop control, choose an estimated target bandwidth of 400 rad/sec. These
BLDC Motor Speed Control with Cascade PI controllers