I am a bit nervous to fire it up but need to finish off the transformers first.
Just slowly bring your Warpverter to life bit by bit.
Start by driving each inverter individually (without its transformer fitted) from the "large" driver waveform. The "large" waveform is a simple 50Hz square wave, so its a lot easier to interpret on the oscilloscope screen than the other more complex waveforms.
Don't be shy about adding dead time. The switching rate is so low, even several microseconds dead time is perfectly o/k.
When testing, it helps a lot to externally trigger your oscilloscope from the 50Hz "large" waveform when looking at other waveforms.
The other driver waveforms look a bit chaotic, and its difficult for the oscilloscope to find something to lock onto otherwise.
When starting out, expect to see massive overshoot on the secondaries of individual transformers.
And also expect to see some pretty crappy ragged looking voltage waveforms initially, that is all perfectly normal so do not panic !
As you start adding inverters, the waveforms smooth right out. With all four inverters working there will finally be a lovely perfectly smooth sine wave.
The reason for the crappy waveforms is that its very difficult for a transformer (any transformer) to generate a square wave current in the secondary.
Just as its very difficult to produce a perfect square wave voltage across a large capacitor.
So the transformers will not work very well into an open circuit or a resistive load
individually.
It will ring, it will overshoot, and be very unhappy.
However, once you start combining the secondaries in series, a really interesting thing happens.
The voltage waveform begins to look more sinusoidal at 50Hz as the steps get smaller.
The current in the secondaries starts to become more sinusoidal as well.
With everything hooked up and working, the combined secondary current eventually becomes a perfect sinusoid, and that smooth unbroken sinusoidal secondary current is reflected back into every primary.
The transformers are very content working with a pure 50Hz sine wave current, and eddy current losses in the transformers will be low as well.
The voltages across all the individual transformer windings will be switching up and down like mad, and be perfectly rectangular and fast, without any sign of ringing or overshoot. But initially, when only part of the whole Warpverter is working, the waveforms can look pretty awful.
So be prepared for that !
Its all very robust. You can connect any inverter to any drive waveform, and any transformer to any inverter.
You can power up inverters without any drive plugged in, plug or unplug the drive waveforms under power.
And swap the phasing of individual inverters around without any mishap.
The final output may look a bit funny, if the phasing of one or more transformers is incorrect, but nothing is going to blow up.
Phasing can be swapped at the input drive to an inverter, or the transformer primary or the transformer secondary.
Whatever causes minimum aesthetic disturbance to the wiring.
Bringing a new Warpverter into the world has now been done by by many other people, and without any drama.
Its a fascinating exercise bringing one of these to life for the very first time.