TIDM-1000: Distortion in Line 3 current waveform during Build2

selvam perumal

Part Number: TIDM-1000

Hi,

During Build2:Closed Current mode control,We found two abnormalities.

1.PF reading in GUI is showing as 0.83 sometimes 0 which is deviating from other 2lines(PF:0.98)

2.After that we probed the current waveform of all three lines.Line 1 and Line 2have proper sine waveform as mentioned in manual.But Line 3 waveform is not purely sinusoidal and has distortions.

The above results are observed at input 40Vrms(L-N)

Refer the attachment for L3 voltage and current waveform.Blue waveform:Input Current

With regards,

P.Selvam.

over 6 years ago

0 Chen Jiang ti over 6 years ago

TI__Genius 16085 points

Hi Selvam,

I can't find the attachement. Can you re-post it?

How about the waveforms and sensing under build 1? Is everything ok?

This issue needs to be figured out before moving on to higher input voltage and next build.

Regards,

Chen

0 selvam perumal over 6 years ago in reply to Chen Jiang ti

Intellectual 535 points

Hi Chen,

I don't know,why you can't see the image.

Waveforms and sensing under build 1 is fine and similar in Line 1 and Line 3.

I have attached Line 1(yellow) and Line 3(Pink) current waveform.Both are not taken at real time,so it will not be in sync.Line 3 waveform is recalled from memory for comparison.

Would current distrortion in line 3 due to control loop oscillation?

Please look into the below image and give your suggestion.

With regards,

Selvam.

0 Chen Jiang ti over 6 years ago in reply to selvam perumal

TI__Genius 16085 points

Hi,

Thanks for sharing the waveform. Could you also post the expression window for both build 1 and build 2?

Are you using the solution in the latest digital power sdk v2.00.01.00? If you are using the latest solution, I don't think the code will be the issue.

I will get back to you probably after Thanksgiving. Thanks for your patience.

Regards,

Chen

0 selvam perumal over 6 years ago in reply to Chen Jiang ti

Intellectual 535 points

Hi chen,

We are using the solution from latest digital power sdk v2.00.01.00.

Build 1 and build 2 expression window are attached.

Awaiting for your reply.

With regards,

Selvam.

0 Chen Jiang ti over 6 years ago in reply to selvam perumal

TI__Genius 16085 points

Hi Selvam,

I am going to test the solution on my side to see if I can reproduce the issue you observed. I just got my setup ready and should be able to give you a feedback by the end of this week.

Regards,

Chen

0 Chen Jiang ti over 6 years ago in reply to selvam perumal

TI__Genius 16085 points

Hi,

I did a quick test and can not reproduce the issue you had so I think if you did not touch the software. There is nothing wrong in the code.

The test below uses a 500ohm load as we mentioned in the user guide.

Build 1:

build 2 with 40V input:

Can you try to repeat the test with the same load and see if you can reproduce the parameters as above? If not, we can further look at the hardware for phase 3.

Regards,

Chen

0 Chen Jiang ti over 6 years ago in reply to Chen Jiang ti

TI__Genius 16085 points

Hi,

Do you have any update on this issue? Thanks.

Regards,

Chen

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TIDM-1000: Distortion in Line 3 current waveform during Build2