90 degree 2 phase inverter project

Discussion in 'The Projects Forum' started by mad659, Mar 2, 2013.

  1. mad659

    Thread Starter New Member

    Mar 2, 2013
    Hi everyone, although I am new here I have read and seen alot of interesting subjects and cicuits on this forum. I have some basic knowledge in electronics and have built various electronic circuits in the past. I am by far no expert but not to shabby either.
    As the title implies I have a project that needs two seperate sine waves that are 90 degrees part, just like the old 2 fase 4 pole generators. I was wondering if there would be a simple circuit that would turn on 1 12vdc/120ac inverter and turn on a second inverter of the same at a certain time interval as to have them running 90 degrees out of fase.
    Was thinking of having some type of peak voltage sensor to the first inverter that would send a signal to turn on the second inverter or maybe an arduino to turn one on and at a preset time the 2nd one would turn on?
    I would varify it with scope. Although they are seperate inverters they would run totally independent circuits.
    Any help or new ideas would be welcomed.
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    So your requirements are:
    Two 120VAC sine waves shifted at 90 degrees?

    Do you have the inverter circuits or want to start everything from scratch?
    A peak detector won't work very good because the sine wave almost doesn't change at it's peak for quite some time. I would prefer to detect when one sinewave passes through zero. Then just count the time it takes for it to get to 90 degrees and start the second inverter. Although I don't know yet what you mean by "start".

    Two completely independent inverters will not have the same frequency so they need to be constantly synchronized.

    Tell us more details of what you already have (circuits etc) and we start from there.
  3. mad659

    Thread Starter New Member

    Mar 2, 2013
    Those would be my basic requirements, 120vac sine waves shifted 90 degrees apart.
    I have 2 off the shelf 12vdc/120vac inverters.

    praondevou, 'Two completely independent inverters will not have the same frequency so they need to be constantly synchronized.'
    Thanks for pointing this out as I had totally overlooked this. You are correct, meaning that my simple idea of 'starting' one inverter and then 'starting' another in a predetermined time may not work so well.
    I try to use the K.I.S.S. principal in all my projects but I'm always open to start from scratch if a better idea comes along.
    One of my ideas was to sync 2 single fase generators together via a toothed belt and sprockets and have a seperate dc motor driving the arrangement. Would work but it would also be a time consuming project whereas something more solid state would be more efficient and less bulky to build.
    I built a circuit involving an arduino that did the job and had an adjustable frequency also. I have my setup drawn on paper, will try to draw it out on my pc so I can post it for others to see because it would be easier to explain that way.