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HV DC to HV AC audio output

Discussion in 'High Voltage' started by moperformance, Apr 4, 2013.

  1. moperformance

    moperformance New Member

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    Hopefully I am in the correct forum for this question (?). Currently we are using a toroidal transformer to produce a audio sine wave output. The dc source is a 126 vdc lithium battery. The sine wave is generated by pwm one high side of the bridge at 32 Khz while holding the corresponding low leg high/on. imagine a full bridge for motor control but by switching directions at 950 Hz. the max output now is around 900 vrms. The transformer is approx 14/1 ratio.
    What I remember from my high voltage days is that by using a center tap transformer the input voltage can be double what actually is available. which would allow a dramatic increase of the output. Can anyone direct me to where this subject is addressed? It's been a long time since my High Voltage days but I would like to begin again.
    Many Thanks in advance for your time and patience.
    Bill
     
  2. MikeMl

    MikeMl Well-Known Member Most Helpful Member

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    Are you proposing applying the H-bridge to one half of the torroid's primary instead of the whole primary? That should double the voltage across the secondary, but be careful if you are drawing any significant power from the secondary, you are doubling the current in the primary. Losses in the primary are proportional to I squared.

    The correct way to do this is to rewire the primary as two identical bifalar-wound half-primaries connected in parallel. That would mean separating the two windings at the tap, and reconnecting the four ends of the two half-primaries so as to make only two connections to the h-bridge. The phasing of the two windings is critical...
     

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    Last edited: Apr 4, 2013

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