Problem with certain STMCWB parameter combinations

[mikemike9141]

Posted on October 27, 2014 at 09:49

Hi Gigi,

I have a motor with rather unusual electrical parameters (low inductance, high number of poles, very high electrical rpm), and the generated output files for these settings are not usable. The compiler complains for a  computed constant not fitting into signed 16-bit integer (cordic parameter CORD_C5, PLL parameter C5). I have attached the project and hope that you can easily reconstruct it. When I look into the header files, I also recognize that one significant digit is lost for the Ls parameter (13uH is converterd to ''#define LS 0.00001'').

Regards

Frank

[Gigi]

Posted on December 12, 2014 at 11:35

Ciao Frank

Did you test using 10uH instead on 13uH? You get the same complains? Or manually writing #define LS 0.000013? Moreover the PLL issue can be ignored because selecting Obs+Cordic the PLL is not used. Thank you for the feedback regarding the generation of wrong value by the WB. I'll take note for the new release. Ciao Gigi 

[mikemike9141]

Posted on March 13, 2015 at 11:40

Hi Gigi,

I solved this by increasing the value to 20uH, the observer does not seem to be too affected by this. However, I do not have a good feeling of how much deviation from the real value I can allow until the observer algorithm can become unstablee in certain conditions. Another question is, what are the conditions where unstability are most likely? Is it low speed, high speed, high accelereation, high decelaration, the transition from motoric to generatoric operation? Regards Frank

[Laurent Ca...]

The question has been moved from the "Motor Control Hardware" section to the "STM32 Motor Control" section (the question is about the STM32 MC SDK). 

Best regards