use MSP430F67791 to calculate three phase voltage & current harmonic distortion and total harmonic distortion

Chen Long Choo

Prodigy 20 points

Other Parts Discussed in Thread: MSP430F6779

Hi All,

Recently i bought the MSP430F6779 evaluation board for three phase meter measuring purpose.

I download the source code and document from the corresponding links.

www.ti.com/.../slaa577. 
www.ti.com/.../TIDM-THREEPHASEMETER-F6779.

However, this source code do no support the calculation of individual phase voltage & current harmonic distortion and total harmonic distortion. Please guide me the way to acquired the harmonic distortion .

Thank you very much .

Best regards,

Chen Logn

over 9 years ago

0 Ryan Brown1 over 9 years ago

TI__Guru**** 208947 points

Chen Logn,

This feature has not been added onto the F6779 EVM software. However, the F67641 EVM’s (www.ti.com/.../TIDM-THREEPHASEMETER-F67641 ) software should have support for the calculation of THD and fundamental readings if the proper macros in emeter-template.h are defined (see the EVM’s design guide for details on the proper macros). If you wants to use this feature in the F6779 you could copy it from the F67461. Please note though that you may need to increase the CPU clock from 16 MHz to 24 MHz in order to do the extra processing.

Regards,
Ryan

0 Chen Long Choo over 9 years ago in reply to Ryan Brown1

Prodigy 20 points

Hi Ryan Bronw1,

Thank for your advise. I will try up. Appreciate your great help.

Best regards,

Chen Long

0 Weiren Tee over 9 years ago in reply to Ryan Brown1

Expert 1100 points

Hi Ryan,

May i ask, what is the highest individual harmonic measurable by the F6779 EVM? The consideration for this will be the ADC accuracy and the processing power of the MCU right?

Regards,
Weiren

0 Ryan Brown1 over 9 years ago in reply to Weiren Tee

TI__Guru**** 208947 points

Hello Weiren,

Only the fundamental and THD is measured. Besides this, no other harmonic information is available. This is in reference to the F67641 software that must be adapted to the F6779 in order to add this feature, the F6779 EVM software itself does not have this support added.

Regards,
Ryan

0 Weiren Tee over 9 years ago in reply to Ryan Brown1

Expert 1100 points

Hi Ryan,

Thanks for your advice.

Could TI supports the individual harmonic measurement function? This function one of the key consideration to shortlist this part. Hope TI can help to support. Thanks.

Regards,

Weiren

0 Ryan Brown1 over 9 years ago in reply to Weiren Tee

TI__Guru**** 208947 points

Hi Weiren,

I do not know of any current plans to support individual harmonic measurement.

Regards,
Ryan

0 Weiren Tee over 9 years ago in reply to Ryan Brown1

Expert 1100 points

Hi Ryan,

Thanks for your feedback. Hope that TI can considering adding in this function to the energy library in the near future.

Regards,

Weiren

0 ABHISHEK PARIKH over 8 years ago in reply to Ryan Brown1

Expert 1635 points

Hello Ryan Brown1

I want to calculate THD for upto 7th or 15th Harmonic so is there any flow diagram available for that.

What I am doing for that is I am taking samples and doing fourier transform of it for 16 samples every cycle and because of that what I get is frequency response of it.

Than I find power of each component by SQRT(real^2 + img^2)

THD=SQRT(3rd Harmonic^2 + 5th Harmonic^2 + 7th Harmonic^2)/ Fundamental

But I am getting incorrect THD.

Regards

Abhishek

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use MSP430F67791 to calculate three phase voltage & current harmonic distortion and total harmonic distortion