Great video as always! I wish I had you as my professor during my studies!

@MarcosAlonsoElectronics

3 ай бұрын

Thanks!

Thanks for the sharing! Before seeing this video, I had too much doubt about sampling effect.

@MarcosAlonsoElectronics

3 ай бұрын

Glad to know. Thanks!

Thank you so much Professor Alonso for another great video.

@MarcosAlonsoElectronics

3 ай бұрын

Thank you!

Great video, I like it, thank you Professor

@MarcosAlonsoElectronics

3 ай бұрын

Thank you!

Thank you for sharing.

@MarcosAlonsoElectronics

3 ай бұрын

You are welcome. Thanks for watching!

All files are available here: github.com/marcosalonsoelectronics/PE-65

Thanks Sir.

@MarcosAlonsoElectronics

3 ай бұрын

Thank you for watching

Thank you for the insightful video. As far as I understood, the main switching frequency in the last example was 200 kHz, i.e. T=5us. What was the point to use 1us sampling time (five times over a period) if PWM is manipulated cycle by cycle only once per 5us? Is any noticeable difference between the sampling of 1 and 5 us? Am I correctly, that oversampling above the PWM frequency allows us to use an antialiasing filter of the higher cut off frequency? Otherwise, if we use fADC = fPWM, because of antialiasing filter we would always have real sampling time at least a half of the PWM frequency?

@MarcosAlonsoElectronics

2 ай бұрын

Thanks for this excellent comment. If we do oversampling we can get a more accurate value of the output voltage just before calculating the new value of the duty cycle. This will make the response more similar to the one we get with the analog version of the closed-loop control. I have done this simulation to show the difference between 1us and 5us sampling period: github.com/marcosalonsoelectronics/PE-65/blob/main/6.-%20buck-digital-control-closed-loop-Tsp-comparison.qsch We can see that the one with 1us is slightly better during the step response. Of course, there are problems in doing oversampling like the noise generated close to the switching instant and the calculation time. So it is true that usually a sampling period equal to the switching period is good enough.

@RogovAB

2 ай бұрын

@@MarcosAlonsoElectronics Thank you for reply. Just found a paper on this topic "How to simplify AFE filtering via high-speed ADCs with internal digital filters" available from TI website. They suggest to use 16MHz fADC instead of 1MHzfADC at 200kHz fPWM in order to replace 5th order antialiasing filter with 2nd order one and performe further filtering within digital domain. But when we use Fadc=fpwm, which antialiasing filter can be use?

See an example of unstable behavior due to too high sampling period here: kzread.infoOr4pFXP9dUk

Marcos Alonso, I love this! Can we be friends?

@MarcosAlonsoElectronics

3 ай бұрын

Thanks! Yes, of course we can be friends