“This is a meaty project so buckle up!
Grid tie inverters enable you to push power into a mains socket which is an awesome ability. I find the power electronics and control systems involved in their design interesting so I built my own. This report shares what I learnt and documents how I did things. I’d be interested in any comments you had (apart from the ones about not messing with mains electricity).
All the concepts are scalable but this setup had a maximum output of 40 watts before the filter inductors began saturating. The output current was sinusoidal with THD < 5%.
See the software on my GitHub
Supplies:
I used the STM32F407 development board. It runs at 168MHz and has 3 built-in ADCs capable of 12bit resolution at over 2.4MSPS (Million Samples Per Second) each. That’s insane!
I used the DRV8301 development board. This houses a 60v H-Bridge along with the necessary gate drivers, current shunts and current shunt amplifiers. Super nice!
I used a 230-25v toroidal transformer with 2 output taps. This meant I didn’t have to directly produce mains voltage but could work with peak voltages of 40 volts instead. Much safer!
I connected a load of inductors and capacitors together to get the L and C values I wanted for the filter.
An oscilloscope and differential probe is key for a project like this. I have a Picoscope”