Simulink Control Design™ - MathWorks

• Sine Amplitudes - Specifies the amplitudes of the injected sine waves. In this
  example, choose 0.25 for the inner-loop controllers and 0.01 for the outer-loop
  controllers to ensure the plant is properly excited within the saturation limit. If the
  excitation amplitude is either too large or too small, it will produce inaccurate
  frequency response estimation results.

Tuning Cascaded Feedback Loops

Because the Closed-Loop PID Autotuner block only tunes one PI controller at a time, the

four controllers must be tuned separately in the FOC ASM model. Tune the inner-loop

controllers first, and then tune the outer-loop controllers.

• The d-axis current controller is tuned between 3.5 and 3.55 sec.


• The q-axis current controller is tuned between 3.6 and 3.65 sec.


• The flux controller is tuned between 3.7 and 4.7 sec.


• The speed controller is tuned between 4.8 and 5.8 sec.

After tuning each PI controller, the controller gains are updated through the Data Store

Memory block.

Simulating Autotuner Block in Normal Mode

In this example, the FOC ASM model is built in Simulink. All four controllers are tuned in

one simulation. In addition, speed responses are compared before and after tuning the

controllers. Scenarios under test include the acceleration process and torque load

changes (magnitude of 1 p.u.).

Simulation of the FOC ASM model usually takes a few minutes on your computer due to

the small sample time of the power electronics controller of the motor.

sim(mdl)

logsout_autotuned = logsout;

save('AutotunedSpeed','logsout_autotuned');

The following figure shows the overall simulation result.

8 PID Autotuning