tezoatlipoca t1_jefjvfd wrote on March 31, 2023 at 5:19 PM

In an AC or alternating current power line, the current flows first one way, then the other. The current, and/or the voltage if you want to think of it that way, literally changes direction (or from +V to -V) following some type of periodic or cycling wave: a square wave, or a sine wave.

The problem is, a lot of power sources that aren't large turbine or rotationally driven generators tend to produce DC or direct current - which does not alternate. Solar panels, batteries etc.

So what a power inverter does is convert a flat Direct Current into a sinusoidal - or at least periodic, repeating - wave. One does this with mechanically flipping switches or relays or with transistors (or derived digital logic circuits), which are really just silicon based switches. For half of the cycle it sends current one way, for the other half it sends current the other way. By designing the output of that circuit carefully with the right components you can essentially get a square wave. By ~~adding~~ removing some additional harmonics with additional switches and components ((diodes, resistors, capacitors)) you can change the shape of that square wave into a sine wave.

konqueror321 t1_jefq0ww wrote on March 31, 2023 at 5:59 PM

So an inverter generator would convert the raw generator AC output into DC, then convert it back into AC output as you described, 'cleaning up' the raw AC current so it is safer for electronic devices?

geekworking t1_jefske9 wrote on March 31, 2023 at 6:16 PM

Yes. The electronic inverter circuit is what is creating the AC output and this can be carefully controlled to give a clean and consistent output. High end online type uninterruptible power supply (UPS) systems designed to protect sensitive computer equipment work in a similar way to take power from the wall outlet or its batteries to always make clean power.

The other advantage to inverter generators is that they can slow down the engine when less power is needed. This saves a lot of fuel and makes them less noisy most of the time. Normal AC generators need to always run a full speed to provide the proper output frequency.

beavis9k t1_jega7k5 wrote on March 31, 2023 at 8:13 PM

Minor correction, if I may: harmonics are removed or canceled out to get a sine wave. A pure sine wave has only one harmonic (the fundamental). A pure square wave is the fundamental and the odd numbered harmonics.