Hopefully? Another 48vdc-240vac Toriod Inverter build.

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wiseguy Guru Joined: 21/06/2018 Location: Australia Posts: 1206	Posted: 10:17pm 27 May 2023         KeepIS said   The inverter is drawing slightly more current producing one half of the AC cycle  compared to the other, this is likely due to having only one choke in one side. The chokes are wound with 4G cable. The current is definitely higher again now, possibly in part due to: A: The total cable used has been halved since remaking the chokes, less R-Loss. B:The interplay of lower inductance chokes on each side, however, combined, a higher inductance by an extra 9uH compared to the single 37uH choke used on one side. Current peaks measured from the base dc offset to the Peak DC current swing is now reaching 568A [26.7kW DC peaks] Measured a few times to confirm and its always the same. The chokes each side should be considered as 1 choke, it is a series circuit and the current through any part of the series circuit will be the same at any given time. The only advantage I saw for splitting the choke was for symmetry when looking at transformer primaries with a CRO and reduction of fast switching edges applied to the transformer so less coupled noise. The current peaks being higher on one side should have zero to do with the choke being on one side. When compared to normal 240V behaviour with regard to current peaks are they identical ? Have you put a heap of resistive loads (all stove elements turned on) for comparison of the current peaks too? If the symmetry issue of current peaks is definitely caused by the inverter my guess would be possibly the dead time capacitors across the LED's of the opto coupler drivers not being matched for each side drive. If there was unequal dead time that could rob one side of energy throughput for the side with the greater dead time, another possible reason is slight asymmetry of the EG8010 output waveforms for each half. Last comment, is it possible that increasing the inductance from 37uH to 46uH has slightly reduced the efficiency at high loads resulting in higher current required to start the same load ? I only ask these questions and make these comments in the interests of being as nice to the inverter as we can be.