# Average Voltage of a 3phase full wave bridge diode rectifier derivation

Why three phase bridge rectified waveform is integrated over the half period $$\\pi/6\$$\ to find the average voltage? Should it not be integrated over $$\\pi/3\$$\, as the wave form repeat itself after $$\\pi/3\$$\ which is the time period of this waveform. Below is the waveform and related derivation. The book is Power Electronics 3rd Edition by Muhammad H. Rashid, page no 93.

## 1 Answer

The waveform from $$\\pi /6\$$ to $$\\pi /3\$$ is just the symmetrical reflection of the waveform from $$\0\$$ to $$\\pi /6\$$. Therefore, the average value will be the same over those two periods.

• I am asking about integrating over two periods from 0 to $\pi/3$\ and from 0 to $\pi/6$\ Commented Jul 11, 2019 at 15:34
• Yes, but the result will be the same because the waveforms during the second half of the $\pi /3$ period are just a reflection of the waveforms in the first half of the same period. Commented Jul 11, 2019 at 16:55