Electronics > Projects, Designs, and Technical Stuff
Single phase to three phase sinewave converter
duak:
Generating 3 phase from 2 phase quadrature is quite easy. It can be done with transformers as in the Scott-T transformer. Looking at it you can see that the B & C phases are basically the A phase with the Q (quadrature) phase either added to or subracted from it. This can be done with opamps and resistors which can then be used to drive some power electronics.
Generating 2 phase quadrature over a frequency range is not as easy but is possible. An allpass filter can be used to generate a phase shifted signal with a particular phase at a particular frequency. Allpass filters can be combined to provide a constant phase shift over a range of frequencies: https://www.edn.com/electronics-blogs/living-analog/4375814/All-pass-filter-phase-shifter To generate just Q for a 50-60 Hz frequency range, I think that only two stages of one chain will be needed rather than the four stages in two chains shown here.
I also think there is an error in the schematic in that resistors R5 to R8 should be exchanged with the capacitor to the right.
Hope this is clear,
Cheers,
soldar:
--- Quote from: duak on January 13, 2019, 07:35:25 pm ---Generating 3 phase from 2 phase quadrature is quite easy.
--- End quote ---
Well, yes, of course. Once you have two signals with different phases you can combine them into any number of phases with any phase offset you choose. That is how vectors work. If you have two or three phase you could combine them to form 5 or 7 or 9 or whatever you wanted.
The problem is that nobody today has a two phase (90º) supply. If they have more than one phase then they will have three phase (120º).
Zero999:
Yes, I think a couple of people here have misread the original post. Here it is again, with the relevant parts highlighted.
--- Quote from: sanwal209 on January 12, 2019, 10:40:53 pm ---Hi Guys,
Is it possible to convert single phase 220AC to three phase synchronized output. If yes, can you please refer me to some documentation.
Best Regards
Sanwal Saleem
--- End quote ---
That's single phase, not two phase, to three phase conversion.
I think a rotary converter is probably the easiest solution, especially as it's only low power.
Yansi:
What are your exact requirements?
Making a three-phase inverter bridge with just fixed output voltage (no current feedback) is so easy. Even adding the synchronization (if you that much need the 3ph output synchronised to mains) would come to just one PI regulator to tune.
All could be done with something as simple and as small as https://www.st.com/resource/en/datasheet/stgipn3h60.pdf controlled by even Attiny261 (any MCU with a three phase PWM timer). Sinewave output could be filtered out of the PWM using suitable LC low pass filters.
So what do you need a 220V 3ph 100mA supply for?
duak:
I know that 2 phase power does not lay thick on the the ground. It's my bad for not tieing it all together by pointing out that the 2 phase quadrature is derived from the single phase input by using allpass filters to implement a phase shifter then simple networks to generate the B & C phasors that could drive a power stage as per the OP's second post:
"i think i didn't ask properly. I am looking for some IC who can drive power stage to generate 3 phase sine wave 220V@100mA while syncing output to the input single ac phase 220V 50Hz. "
I think the circuit could be implemented with one quad opamp and a handful of Rs & Cs.
Cheers,
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