## KM34Z128 - DRM147 - Phase delay

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## KM34Z128 - DRM147 - Phase delay

344 Views
Contributor III

HI,

Referring to DRM147  @ https://www.nxp.com/docs/en/application-note/DRM147.pdf

How to calculate timer value for certain phase angle drift to correct, in short how to calculate timer value to correct phase delay.

and according to DRM147 firmware, how much phase delay maximum we can correct and what is the LSB.

Regards

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• ### Kinetis M Series MCUs

1 Solution
171 Views
NXP TechSupport

Hi @phamsa

Here is the feedback of my colleages !

When the TMR runs @24e6 Hz. , since it is  a 16 bit timer,  it  can compensate maximum 2.73 msec.

2.73ms @ 50 Hz => 49 degrees (since there are 50 cycles of 360 degrees of sine waves).

So, 49.12 degrees or 0.857 rads is the maximum the TMR can compensate for phase.

Therefore, 49.12/2^16 degrees or 0.857/2^16 rads.

It yields 0.00075 degrees or 1.33514404296875e-5 rads is the resolution, i.e., per bit phase compensation.

Yours,

Diego

7 Replies
214 Views
NXP TechSupport

I will  consult this with my colleages in order to provide you guidance since I am not expert on this topic.

In the meantime, is there any other detail regarding the  application that we may consider?

I appreciate your patience, thank you!

Diego

214 Views
Contributor III

HI Diego,

Application is 3 Phase energy meter, concert is that the delay provided by timers can take care of delay caused by CTs used in current days meters, normally in this application CTs used is made of Amorphous Core, so approximately 4 degrees to 7 degrees caused by these CTs.

I am concerned of the method followed in DRM147 to compensate phase angle can be handled or not.

Thanks,

Regards

214 Views
NXP TechSupport

I will let you know our feedback as soon as I can.

Thank you!

Diego.

214 Views
NXP TechSupport

I just want to let you know that we are waiting software engineer confirmation of our feedback,

When we get his confirmation, I will reply this ASAP.

Thank you.

201 Views
NXP TechSupport

This may take additional time, since we have been double checking our reply with the software engineer.

I appreciate your great patience; I will let you know our results as soon we finish our internal validation.
Regards, Diego.

172 Views
NXP TechSupport

Hi @phamsa

Here is the feedback of my colleages !

When the TMR runs @24e6 Hz. , since it is  a 16 bit timer,  it  can compensate maximum 2.73 msec.

2.73ms @ 50 Hz => 49 degrees (since there are 50 cycles of 360 degrees of sine waves).

So, 49.12 degrees or 0.857 rads is the maximum the TMR can compensate for phase.

Therefore, 49.12/2^16 degrees or 0.857/2^16 rads.

It yields 0.00075 degrees or 1.33514404296875e-5 rads is the resolution, i.e., per bit phase compensation.

Yours,

Diego

140 Views
Contributor III

Thanks a lot,

Now I got clear understanding on this topic.

I also did some exercise and understood that timer can help in getting delay but we have limitation of sample to sample time and for my use case I can hardly able to adjust 1 degree

Thanks a lot for your support

Regards,