I have a voltage inverter that converts a 400VDC source into sine wave of 240VAC @ 50Hz. The inverter is based on a H-Bridge. The inverter works well but I'm struggling in understand how to control the output voltage incase the output rises or falls above the desired value (240VAC). The MCU driving the H-Bridge reads the output voltage via a step down transformer.
Will Proportional Control only work or do I need to implement PI? I was considering implementing something as follows: if actual voltage is less than desired voltage, increase duty cycle by 5%. Keep increasing the duty cycle by 5% till the output gets to 240VAC.
If the output voltage is higher than 240VAC, we decrease the duty cycle by 5% per iteration till we get to the desired output.
Is such a scheme likely to make the system unstable? Is there a better way to do this?