Bipolar DCDC with bipolar output (battery to 3 Phase converter)

[Amper]

Hi!

Im working on a battery to 3 phase converter, for now to power aircraft electronics at 400Hz 115V from 24V but when things work id like to build a larger version for off grid applications.
To power symmetrical loads like motors or heaters just having a single dcdc generating the dclink voltage is enough of cause but when DC offset and or asymetric loads come into play, things start getting interesting. To my knowledge generating a proper neutral taht can handle load in any direction will require my dcdc to provide a positive and a negative rail that are both regulated/ symmetrical even under unequal load.

The obvious path is just to use two independant DCDCs, each with its own regulation but mirrored.
While this will work im afraid if things go wrong and i loose one rail due to an error in regulation, high load or any other thing i cant think of i will generate a DC offset on teh output of my converter wich can easily fry whatever is connected.

Thats why im looking for a topology that allows inductive coupling of the mirrored paths.
A converter using an (ideal) transformer would provide me with two rails that are exactly the winding ratio apart, also i could use one output winding and a voltage doubler that will generate symmetrical outputs. However those topologies will all either require a sine input or some kind of inductor to limit peak currents. Sine is not really an option and inductors will "soften" the rails differently, so the coupling will not be there anymore.

Is there some other way?
Maybe coupling the output inductors?
How is this done in commercial 3 phase converters?

I just noticed, it does seem to work somewhat if both channels are in continuous mode after the current is high enough.

(The screenshot shows my idea about the coupled inductors wich does not seem to work, the transformer was left out and repllaced by the source)

[NiHaoMike]

The obvious path is just to use two independant DCDCs, each with its own regulation but mirrored.
While this will work im afraid if things go wrong and i loose one rail due to an error in regulation, high load or any other thing i cant think of i will generate a DC offset on teh output of my converter wich can easily fry whatever is connected.

Add a circuit to detect excessive DC offset and shut down the converters, exactly as what's done in audio amplifiers.