inverter efficiency

While looking for larger inverters, I found these:
http://www.exeltech.com/ex_root/ex_products/ex_inverters/ex_mx/ex_mx_series.htm
But the efficiency is not very good, only in the 87% to 90% range. I would think that with today's digital techniques, much better, like 96%, would be possible. Can anyone reliably or authoritatively comment on what kinds of efficiency is really possible from the different inverter technologies, especially the digital ones?
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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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snipped-for-privacy@ipal.net wrote:

Most power losses come from to the switch used to control the current flow. Even in the "on" condition, there's some voltage drop, with a fixed loss of E X I watts. E is usually constant, so at a higher switched voltage, the overall efficiency is higher. There's a trade off between switch device voltage ratings and costs.
The way the current "switch" is controlled, digital or otherwise does not have much to do with the over-all efficiency, assuming the switches are controlled in an intelligent manner.
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| snipped-for-privacy@ipal.net wrote: |> While looking for larger inverters, I found these: |> |> http://www.exeltech.com/ex_root/ex_products/ex_inverters/ex_mx/ex_mx_series.htm |> |> But the efficiency is not very good, only in the 87% to 90% range. I would |> think that with today's digital techniques, much better, like 96%, would be |> possible. Can anyone reliably or authoritatively comment on what kinds of |> efficiency is really possible from the different inverter technologies, |> especially the digital ones? |> | Most power losses come from to the switch used to control the current | flow. Even in the "on" condition, there's some voltage drop, with a | fixed loss of E X I watts. E is usually constant, so at a higher | switched voltage, the overall efficiency is higher. There's a trade off | between switch device voltage ratings and costs. | | The way the current "switch" is controlled, digital or otherwise does | not have much to do with the over-all efficiency, assuming the switches | are controlled in an intelligent manner.
What about the amount of power far away from 60 Hz that is filtered out by the low pass filter?
I found another inverter at 96% efficiency. But this one has a very low fault current capability. Maybe they all do. Maybe I need to design my own.
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snipped-for-privacy@ipal.net wrote:

You can go to the manufacturers' web sites and get the figures for various types and models.
But, generally, the better approximation to a sine wave output you need, the greater the losses. Some "inverters" intended for powering equipment with smpsu, only, run at 98% efficiency - but have a dc output..
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| snipped-for-privacy@ipal.net wrote: |> While looking for larger inverters, I found these: |> |> http://www.exeltech.com/ex_root/ex_products/ex_inverters/ex_mx/ex_mx_series.htm |> |> But the efficiency is not very good, only in the 87% to 90% range. I would |> think that with today's digital techniques, much better, like 96%, would be |> possible. Can anyone reliably or authoritatively comment on what kinds of |> efficiency is really possible from the different inverter technologies, |> especially the digital ones? |> | You can go to the manufacturers' web sites and get the figures for | various types and models.
For some you can. Many have rather poor web sites and make this info hard to find.
| But, generally, the better approximation to a sine wave output you need, | the greater the losses. Some "inverters" intended for powering equipment | with smpsu, only, run at 98% efficiency - but have a dc output..
I think I need to find some inverter schematics for typical modern designs and see just what they are doing at least to compare against what I think they should be doing.
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