how to select the bandwidth of the speed loop and the PLL

[董培董]

hello,I read the document of the 《MC9S12ZVMMCLUG》，there are some questions about the parameters setting,as follows

1、How to select the bandwidth of the current loop?

2、How to select the bandwidth of the speed loop?

3、How to  select the bandwidth of the PLL?

Is there any relevant document or paper? 

thank you very much！

[dianabatrlova]

Hello,

The PI Controller parameter tuning can be done also using the MCAT tool provided with our PMSM motor control examples. In such a case, you can follow AN4642 or AN4912 accordingly.

https://www.nxp.com/docs/en/application-note/AN4642.pdf

https://www.nxp.com/docs/en/application-note/AN4912.pdf

Best regards,

Diana

[董培董]

Hi Diana

Thank you very much!!!

your method is very effective, I use  the method all the time,but it is the trial and error method ,

so I want to know how are these parameters determined by the theoretical analysis or test.

and I set the PLL transmission function as the type 2 system,then select h=5,but I can't get valid parameters.

so I want to ask you for some help ,thank you!!!

Best regards,

Dong

[pachamatej]

Hi Dong,

I'm afraid the task you are up to is very application specific and normally it would be highly recommended to do a trial&error method for that.

The idea behind the bandwidth and attenuation is more related to the dynamic states, in terms of frequency, and it refers to Bode diagram of a closed loop system. So if you know what is your system dynamic parameters, then you would be able to set the parameters accordingly (e.g if you have your system modeled in MATLAB, you can identify your control loop parameters).

If you are more familiar with PI controller settings with individual P and I constants tuning, then you can use it for GFLIB_ControllerPIp with direct interface to Kp and Ki constants or, using formulas to calculate CC1 and CC2 for GFLIB_ControllerPIr.

Finally, there is this trial&error method, which is suitable mainly for speed loop settings. However, some initial settings may help you to start.

Anyway, I would recommend you to start using MCAT. In attachment, you'll find some guidance I have prepared for current loop tuning. Speed loop tuning can be done accordingly, but then it is necessary to have reliable speed feedback. If you use sensorless algorithm, then please make sure first that the algorithm is set correctly.

I hope it helps.

Best regards,

Matej