Hello,
I'm trying to design a pure sine wave inverter based on an AVR MCU but I'm not really sure what kind of design I should go with. So far I've managed to implement sPWM on an ATmega328 and verified that it was working as it should with the help of two low-pass filters. (Attached a picture of the waveforms.)
I've tried experimenting with a 24v:220v center-tapped transformer (1uF film capacitor connected to primary for filtering and the center tap of the secondary connected to 12v) and I've had mixed results. I've tried connecting the remaining two connections of the secondary to GND via two mosfets and tried to drive them with a TC4427 but I got a waveform that looked like a deformed square wave so I replaced the mosfets and the TC4427 with two BC548s and two MJE13007s which resulted with a perfect sine wave at the primary but the voltage was around 140VRMS instead of 220VRMS.
Firstly, should I just ditch the idea of using a center-tapped transformer? I saw other designs which use a DC/DC converter to convert 12V into 310V and a H bridge to modulate 310V DC into 220V AC and honestly they just seem more suitable. If a center-tapped transformer is suitable for such an application, how can I get the transformer to output 220VRMS instead of 140VRMS? I've attached the source code of my sPWM program. Honestly, it feels like I'm missing something obvious.
This is my first post here so sorry if this is not the right thread for such questions.