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MSP430F6779A: Three Phase Energy meter calibration sources

NILESH MOTAWALA
Prodigy 100 points
Part Number: MSP430F6779A
Other Parts Discussed in Thread: MSP430F6779, , EVM430-F6779

Hello,

        I am using 3-phase electricity meter EVM with integrated MSP430F6779 device for development and Energy measurement. But i cant not decide the proper AC sources like RESISTOR and INDUCTOR ( for proper power factor calibration) value  for calibrated the device. So please suggest this Resistor and Inductor value.

Thanking You,

Nilesh Motawala

  • 0
    TI__Mastermind 49692 points

    Hello,

    NILESH MOTAWALA said:
    I am using 3-phase electricity meter EVM with integrated MSP430F6779 device for development and Energy measurement.

    Thanks for your interest in our MSP430 devices. While the non-A version MSP430F6779 device is fine for evaluation, I would recommend that you use the A-version device, the MSP430F6779A. You can find out the differences (improvements) between them by reading through the Differences Between MSP430F67xx and MSP430F67xxA Devices app note.

    NILESH MOTAWALA said:
    But i cant not decide the proper AC sources like RESISTOR and INDUCTOR ( for proper power factor calibration) value  for calibrated the device. So please suggest this Resistor and Inductor value.

    I'm sorry, but you'll have to be more specific. Are you asking how to pick the proper burden resistor for your Current Transformer (CT)?

    Have you heard about our newer Energy Measurement Design Center (EMDC) GUI and Software Library? The MSP430F6779A is supported, and there are many advantages to using this software over the legacy Energy Library including easier configuration, migration between devices, calibration, automated code generation, etc. You can learn more about EMDC from the following resources:

    Regards,

    James

  • 0 in reply to James Evans
    Prodigy 100 points

    Dear James,

             first of all thank you for your kind support.

             My point is that ,i am wondering about the calibration process for the TI Three phase energy EVM430-F6779 meter evolution board,

     I refer the link training.ti.com/build-your-own-energy-meter for the calibration process.But i can't decide the Resistor and Inductor ratings for  the power factor calibration. and cause of this  

     I cant get the the exact Active power due to imperfect power factor when my load is inductive.( for resistive load all is working fine).

             Please guide me for choose the What value of Ac sources is use to calibrate the same device.

            as an example( 230v Ac source with 1A for resistive load ) but what which type of inductive load have to  use for the power factor correction(Inductive load).

    I would like to mention that i am using slaa577g.zip. as a reference code and calibration software.

    Regards,

    Nilesh Motawala

  • 0 in reply to NILESH MOTAWALA
    TI__Mastermind 49692 points

    Hello,

    Thanks for sharing the link to this training - it helps frame the context of your question and makes helping easier! On the training video's webpage, I'd recommend downloading the slides in the .pdf format. Then, take a look at Slide 65. There's a very helpful equation for calculating the desired phase angle using the resistor and inductor.

    Since we typically perform phase calibration at 60 degrees (PF = 0.5), then let's assume we have an inductor value, XL, equal to 1H. Now, we need to pick a resistor value, R, to achieve 60 degrees phase shift. Since XL is 1H, using R = 218 Ohms will get us to nearly 60 degrees (59.955 degrees to be exact, close enough). After using these values for XL and R, perform the phase calibration on your board. Then, you should get more accurate results when your load is inductive.

    For the most accurate calibration, a high accuracy test setup is recommended but they're not always available. Thus, this method is an excellent alternative. Please let me know if you have any questions.

    Regards,

    James

  • 0 in reply to James Evans
    Prodigy 100 points

    Hello James,

                           You suggest me for 1 H inductor,but practically it is too big and what i am looking in to the  this training video is small inductor.That one is not possible as per my knowledge.I also done enquiry in local market for the this type of Inductor but didn't get any positive response.

    Can you please guide me.

    Regards,

    Nilesh Motawala

  • 0 in reply to NILESH MOTAWALA
    TI__Mastermind 49692 points
    Hello,

    You can use the equation highlighted above to choose an inductor in an available size and then calculate the required resistance to achieve a 60 degree phase angle (or PF = 0.5).

    Regards,

    James

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