As you turn off your MOSFET there will be a reverse current from the transformer. In H bridge that is normally passed through the free wheeling diodes.
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No need to lower the PWM frequency, you need to make some arrangement to manage the reactive power during turn OFF. Kindly refer the other inverter whether they have dead band shorting MOSFET's also the pwm frequency.
By dead band shorting you mean a dead time between the end and the start of the opposing signal?
How would this schematic look if I used H bridge? Do I need to change the code or just feed the same signal to the opposite corner MOSFETs? I mean appart from the high side switching driver.
The result is rather unspecific, though. Can be a case of wrong switching pattern or leakage inductance generated overvoltage increasing a bit when activating push-pull operation. Need to look at the waveform details.
I believe a push-pull with one primary leg open, devolves
to a flyback (primary upside down, but still).
Now one thing I see missing from this push-pull design is
the "flywheel" inductor that keeps the secondary current
circulating (rather than extinction each half cycle).
There is only the transformer, bridge and load.
Hi,
I rather expect 12mH than 12uH...
How did you measure it?
Klaus
Hi,
Again: how did you measure it?
I mean: the primary side has three connections but the meter usually only two.
And what frequency, what voltage/current, pure sine?
Klaus
The other two shorted? --> This explains the low inductance.I measured center tap to the other two. Common to ct and then i changed.
Hi,
The other two shorted? --> This explains the low inductance.
Let's assume you have a transformer with split output...would you ever short them, too?
Useful measurement setup is to measure just a single winding (leaving the other open), or to measure both windings in series (leaving the center tap not connected).
Klaus
If you measure it in situ then you will see that secondary
"shorting" cap reflected back to the primary. That might
mess up an inductance meter's idea of what it's looking at.
'in situ' means 'while connected in the circuit'. To do the tests you need to disconnect all the windings then check each one as before.
Brian.
By feeding the complement signal to the bottom MOSFET (with few micro seconds dead time) . You can easily convert it to h bridge. Make sure that you use split bobbin transformer.
Hey,
I have 2 signals with spwm and plenty of dead time between them. What i saw about H Bridge is I must feed the one signal to the A and D mosfets and the other to B and C mosfets. Will this work this way assuming i have 100+uS between the signals?
View attachment 148326
View attachment 148327
Why use split bobbin transformer? The ones i have are single bobin ones. Whats the difference of a "normal" one except better isolation?
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