Alternative Power Inverter design

[daviddawe1982]

Hello All,
I have been playing around with a custom inverter build and while programming the controller I had a thought.
50/60Hz is not ideal for a voltage conversion frequency so why not do the dc to ac at say 100khz then rectify that back to dc then run a second H bridge to modulate the high voltage dc at 50hz.
It would require a smaller transformer and the HV side switching would only require a few MOSFETs...
I the first thought was a high current boost step-up circuit but I would then get voltage spikes as loads came on and off.(Please correct me if I am wrong).
So my current idea is..
DC LV HF h bridge -- Smaller Transformer -- Full Bridge Rectifier -- DC HV LF h bridge  -- Filter For Sine.
What are peoples thorghts ?
Has it been done and did it work?
Just thought I would ask before going to far off track with my current design.
Thanks.

[petect]

Hi Dave
Have you been to    https://www.thebackshed.com/forum/home.asp

Your fellow Aussies are doing a lot with inverters there.
Pete

[joestue]

What you've described is whats in most cheap modified sine wave inverters, many computer backup supplies. and many sine wave inverters.

Above maybe 5KW, a 60hz transformer can compete with a double conversion dc-ac-dc-ac inverter.

[mab]

well it's certainly do-able, but I'm not sure the advantaage of a smaller transformer offsets the disadvantage of having a one-way inverter - with a big 50hz trans you can AC couple pv/ generators and  backfeed the inverter - i don't think that works with 2 stage inverters. Also your surge capability tends to be limited by the capacitor bank storing your HVDC - hence the best inverters for starting motors are the low frequency type .