Can someone help with calculating modified sine wave true RMS value and also how to Control PWM dutycycle to maintain fixed output.
Example: input volatge 100Vdc.
Need to maintain fixed Vrms 50VAC
Frequency = 50hz
Modified sine wave same as in the picture
For PWM with duty cycle d,
Vrms = sqrt(d * Vin**2) = sqrt(d) * Vin
so
sqrt(d) = Vrms / Vin
or
d = (Vrms / Vin) ** 2
So for Vin = 100V and Vrms = 50V, you want d = 1/4.
The frequency doesn't come into it.