How... Modified... is modified/simulated sine wave.

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BasBas

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Inverters like the mecer 1200VA/2400VA as well as the Ellies inverters market themselves as simulated sine wave or modified sine wave.

I am curious to know if anyone has hooked a scope up to any of these inverters and actually observed the output voltage wave form.

Are they just square wave inverters? Is their some amount of stepping involved in the wave?
 
I haven't looked at the Mecer specifically but I think you can assume they're all much the same.

Would be more accurate to call them modified square waves. Like this:

Sine-Wave_DC-AC_Diagrams-nobg-01-1024x322.png


A square wave with a step at zero.

Technically "pure sine" is also built from a square wave, but the switching frequency is orders of magnitude higher, so it's very clean at the 50 Hz scale.
 
You would need to hook up an osciliscope to see as they don't share that info.
Usually when you get to around 7 steps its pretty decent.
 
BasBas said:
Inverters like the mecer 1200VA/2400VA as well as the Ellies inverters market themselves as simulated sine wave or modified sine wave.

I am curious to know if anyone has hooked a scope up to any of these inverters and actually observed the output voltage wave form.

Are they just square wave inverters? Is their some amount of stepping involved in the wave?
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the mosfets clip the sine wave .its not as bad as some think on a decent machine .so instead of switching extremely fast to give a smooth cycle ,little bits are chopped off ,some can go as low as 176 volts . basically your inverters mosfets switch to give you around 12 v ac or voltage of battery in ac ,that is then upped via transformers to the required output voltage .the better the copper is in the transformer the better your ac will be .bad quality mosfets or unmatched pairs will compromise the ac output to the torroidals .
also mosfets create heat while switching ,so some run at 150 deg c quite happily .most decent units use around 6 matched mosfet sets .
 
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BasBas said:
if you sponsor the oscilloscope, i will happily perform the tests.:ROFL:
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ill see if my daughter feels like getting a scope on a unit this weekend ,but also remember its baseless as some inverters switch from modified to full sinewave depending on the load .modified is much more power conscious than full because the switching is done at a lower frequency ,so instead of say 25000 steps per second it will drop to say 12000 steps per second .
 
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