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MSP430F6734A: Solutoin of kwh meter can measure until 50th harmonics

Part Number: MSP430F6734A
Other Parts Discussed in Thread: EVM430-F6736, TIDM-THDREADING

Hi TI Folk,

  Good day to you.

  Please advise that do the MSP430F6734A has capability to measure kwh until its 50th harmonics? if have, that please guide how to achieve this target, and how to simulate this in EVM EVM430-F6736 ?

Best regards

Jiang WeiJi

  • Hello Jiang,

    I'm looking into your request.

    Regards,

    James

    MSP Customer Applications
  • Hi James,

      Good day to you.

      Thanks, will wait for you.

    Best regards

    Jiang WeiJi

  • Hello Jiang WeiJi,

    Thanks for your patience here. Unfortunately, after looking through our many reference designs, I couldn't find one that measures harmonics up to the 50th harmonic. Technically, it should be possible to do this, but would take some effort to implement.

    First, let me point you to our Total Harmonic Distortion Measurement For Energy Monitoring Reference Design (TIDM-THDREADING) based on the MSP430F67xx device. In Section 6, the User's Guide discusses different harmonic test conditions: no harmonics, some harmonics, and combination of harmonics. Basically, the measured versus actual THD values aren't much different for these harmonics, as you can observe in Section 8.

    However, the roll-off from the sinc3 filter (shown below) in the Sigma-Delta (SD) module greatly attenuates the amplitudes of the higher harmonics. This would cause the differences between the actual and measured THD values to be several percent.

    To compensate for this attenuation, you could perform an FFT that estimates the amplitudes of the harmonics at the different frequency components. After getting these amplitudes, you'd have to scale them with a scaling factor to reverse the attenuation effects from the sinc3 filter at the higher frequencies.

    To perform the FFT, you can utilize our DSPLib API's. There are several FFT examples available.

    Hopefully this helps.

    Regards,

    James

    MSP Customer Applications

  • Hi James,
    Good day to you.
    Thanks for your details information.
    Best regards.
    Jiang WeiJi
  • As a follow-up, I wanted to point out these resources as well.

    Regards,

    James

    MSP Customer Applications