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Original question:

AMC1100: AC voltage measurement with AMC1100

AMC1100: AMC1100

Amol Walke
Prodigy 10 points
Part Number: AMC1100
Other Parts Discussed in Thread: TINA-TI, AMC131M03, AMC3330

Hi Alexander Smith, I am working on a similar project where I need to measure the 3 Phase voltage, its a 3 phase 3 wire system means no neutral. I have gone through the Split-Tap Connection for Line-to-Line Isolated Voltage Measurement document https://www.ti.com/lit/an/sbaa553/sbaa553.pdf and finalize below circuit for AMC1100. Please confirm will this work with event of one phase lose and in imbalances in input voltage. 

Thank you.

Amol  

  

  • 0
    TI__Guru 56172 points

    Hi Amol,

    You would not be able to tie both high side grounds of the AMC1100's together. I recommend simulating this circuit in TINA-TI, which can be found on the AMC1100 product page. 

  • 0 in reply to Alexander Smith
    Prodigy 10 points

    Hi Alexander, I kept separate the AMC1100 primary and secondary side GND as mentioned in schematic1 picture.

    Are you mentioning the tying of two high side ground of two AMC1100's primary side as mentioned in schematic2 picture. If yes then to make it separate I need to power two AMC1100 from two different power supply or a dual output power supply to get two ground. Even though I will do this but it will not electrically isolated as both AMC's will get signal from Y Phase. Please help to solve this.

     

  • 0 in reply to Amol Walke
    Prodigy 10 points

    Hi Alexander, Any feedback on my query. Please suggest any reference design for measuring 3 phase 3 wire system.

    Thanks 

    Amol 

  • 0 in reply to Amol Walke
    TI__Guru 56172 points

    Hi Amol,

    For measuring L-L voltages, please see this document: https://www.ti.com/lit/an/sbaa553/sbaa553.pdf

    If wanting to measure 3 L-N voltages, I recommend considering the AMC131M03 and measuring all voltages with respect to neutral. 

  • 0 in reply to Alexander Smith
    Prodigy 10 points

    Hi Alexander, Thank you very much for your time to reply me. I have gone through the document https://www.ti.com/lit/an/sbaa553/sbaa553.pdf. As I need to measure L-L with NO neutral I looked into the sentence mentioned in this document: By using the split-tap configuration on a balanced three-phase AC voltage system, two line-to-line voltage measurements are sufficient to measure all three line-to-neutral voltages through derivation.  

    So I need to use two AMC3330, one for Va-Vb and second for Vb-Vc. The document mentioned for Va-Vb and not mentioned for Vb-Vc circuit so I assume it should be similar to below drawn schematic.

    I have used one isolated power supply to power both AMC3330 and kept high side ground (HGND) same for both, where as lower side GND are isolated from HGND. Please share your feedback on this, it will really a great help to me to close the project fast.

    Thank you again for your time.

    Amol 

     

  • +1 in reply to Amol Walke
    TI__Guru 56172 points

    Hi Amol,

    AMC3330 has an integrated DC/DC converter, deriving the high side supply is not necessary. 

    You cannot use the same high side (VDD1, GND1) supply for both AMC1100 in the 2x L-L measurement configuration as you have shown. You would need separate supplies. The voltage potential at the mid-point between Y-B and Y-R is not the same. Your single supply would create a short between the phases. 

  • 0 in reply to Alexander Smith
    Prodigy 10 points

    Hi Alexander, 

    Thank you very much for your time to reply my message. I total understand the two mid-point of Y-R and Y-B will have a different voltage and connecting to-gather will create a short. So I need to power two AMC1100 with two different power supply and keep separate HGND1 and HGND2, with this each AMC1100 will work independently for two 2xL-L measurement. I updated the schematic as below, request please suggest any modification required your feedback will be great help.

           

  • 0 in reply to Amol Walke
    Prodigy 10 points

    Hi Alexander, Any feedback on schematic shared. Need to know can we use AMC1100 for 2xL-L measurement? Your feedback will real help to close my design.

    Amol   

  • 0 in reply to Amol Walke
    Prodigy 10 points

    Hi Alexander, waiting for your valuable feedback, please help to close my design.

    Amol

  • 0 in reply to Amol Walke
    TI__Guru 56172 points

    Yes, I think this is fine.