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Hi,
I am trying to tune the cascaded PI controller for 3.3kW PFC. The cascaded PI controller has outer voltage Loop and a inner current loop. How should I approach to choose the correct Kp , Ki values for both Loops for different load current and for Input RMS voltage of 200 to 250v.
CASCADED PI CONTROLLER LOOP
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Hello @Rakesh_rp
Thanks for posting your question in Infineon community.
The Kp,Ki calculation explained in the below steps
Step:1 Model your system(converter and controller) and write equations in Continuous Domain(S-domain) and convert in Discrete Domain(Z-Domain).
Step:2 add if any delay is presented in the system and write an open-loop transfer function.
Step:3 Plot Bode plots (Magnitude and Phase Plot) and check the system stability. The stability can check by using the Phase margin.
Step-4 Kindly maintain a phase margin of 45 deg and accordingly tune your Kp and Ki Values.
Step-5 Try to model your outer voltage loop separately and your inner loop separately.
Note: Outer loop should be slower than the inner loop accordingly inner loop Kp, Ki should be selected
Thank you
Guru
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Hello @Rakesh_rp
Thanks for posting your question in Infineon community.
The Kp,Ki calculation explained in the below steps
Step:1 Model your system(converter and controller) and write equations in Continuous Domain(S-domain) and convert in Discrete Domain(Z-Domain).
Step:2 add if any delay is presented in the system and write an open-loop transfer function.
Step:3 Plot Bode plots (Magnitude and Phase Plot) and check the system stability. The stability can check by using the Phase margin.
Step-4 Kindly maintain a phase margin of 45 deg and accordingly tune your Kp and Ki Values.
Step-5 Try to model your outer voltage loop separately and your inner loop separately.
Note: Outer loop should be slower than the inner loop accordingly inner loop Kp, Ki should be selected
Thank you
Guru