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Original question:

THVD8000: communication over an 220 VAC line?

THVD8000: Power line communication over 230 V c.a. twisted pair

Norbert REDONDO MELCHOR
Prodigy 40 points
Part Number: THVD8000

Hello All:

I've already ordered 6 THVD8000 bare integrated circuits to start testing communications over 230 V a.c. line.

Our goal is to control up to 20 passive loads (roughly 1 A each) derived at regular intervals from a power line composed by two aluminum 16 mm2 twisted cables (line+neutral), fed from one end only. Kind of a row of 20 street lamps supplied from the same phase. We aim to switch each load on-off  independently from commands issued to the power line from the feeding end. Reliability would be essential, we can not afford to loose data packets. Speed is not crucial, just reliability.

If anyone can share their experiences related to this subject I would be very grateful. I'll try to do it too.

Cordialmente,

Norbert.

  • 0
    TI__Mastermind 25705 points

    Norbert,

    Thanks for your interest in THVD8000, which is a new concept for power line communication. Like I mentioned in other posts, we haven't gone that far to test THVD8000 with the main AC supply. The highest AC voltage has been proved working was around 24V. The main challenge here is that the system needs to attenuate 230V to become much less 15V (the THVD8000 bus abs max) to prevent the device from getting damaged. For illustration, I draw a plot for your reference. The inductor's impedance (RL1/RL2) at 50Hz should be high enough (comparing to RL), which might not be practical. 

    We're also actively investigating the possible solutions.

    Regards,

    Hao

  • 0 in reply to Hao L
    Prodigy 40 points

    Thanks for your answer Hao.

    A 230 V / 15 V miniature transformer might solve that voltage issue? (nominal power of this transformer would be minimal).

    According to our experience, based on actual measurements, this transformer shouldn´t negatively affect the signal from/to THVD8000.
     What do you think?

    Many tanks again.

    Norbert.

  • 0 in reply to Norbert REDONDO MELCHOR
    Prodigy 40 points

    I've prepared a picture on the idea, not as pretty as yours, but your forum platform refuses to show it (the picture should be next line from this one...)

  • 0 in reply to Norbert REDONDO MELCHOR
    Prodigy 40 points

    Another try whit my picture (using 'Insert File' to include a .PNG...)

    More over, increasing the capacitance of C1 & C2 the voltage drop across them could do the trick: with roughly 2 µF each we would be applying just under 8 V rms to A-B inputs of THVD8000, provided its equivalent (internal) impedance would be 120 Ω (driving a current from the condensers around 70 mA...) In that case, the transformer would not be necessary.

    Let me know your thoughts please.
    Norbert

  • 0 in reply to Norbert REDONDO MELCHOR
    TI__Mastermind 25705 points

    Norbert,

    I like your idea of inserting a transformer. I think it should work however I've never tried this method (or any transformer on bus).

    Increasing the capacitance works for the protection but it might attenuate the signal too much (with 120Ohm termination). 

    Please let me know if you have more questions.

    Regards,

    Hao