I am going to make two pure sine inverters for collage project.
Both inverter uses 24V battery as DC voltage source. Switched to ~360Vdc and ~180Vd by boost converter accordingly. Both then switched by IGBT full H-bridge circuit to SPWM AC. There is control circuit which has output od modulated sine wave(50Hz and 60Hz) with 20kHz carrier frequency. This controller drives the H-bridge. At this point everything works perfectly fine as expected. But now to get a proper sine wave instead of a SPWM wave, i need to add filter circuit. I am not sure how to design filter.
Some of suggestions i got from experts that you need a low-pass filter to filter the 20kHz. But dont know how to design one.
How to select L and C values? Is there any equations or calculation for this? Which topology should i use? Does hormonics removed completely by adding low-pass filter?
Case 1: I/p voltage: 360 Vdc Output voltage: 250 Vrms@50Hz Output current: 5Amp max Total power: ~1250VA max
Case 2: I/p voltage: 180 Vdc Output voltage: 120 Vrms@60Hz Output current: 8Amp max Total power: ~1000max
Thank you for help me. Please correct me if i am wrong and assume appropriate parameters/values if i missed to describe.