Electronics > Projects, Designs, and Technical Stuff
Single phase to three phase sinewave converter
Yansi:
Forget analog filters. It won't be precise and stable enough, not really something botched up from a quad opamp package. But still, I haven't noticed you specifying the purpose of this 3ph generator, so hard to judge if that would suffice or not.
Even if you could produce three sine waves 120 degree apart using few opamps, whats your plan of amplification up to 220Vac? This analog solution just does not make much sense. The digital route is definitely easier one.
You may probably find MC3PHAC integrated circuit. Which if I remember correctly is some preprogrammed 8bit MCU or what. Very expensive, probably very obsolete too. But can produce 3ph PWM to drive a power stage, and probably could be frequency locked on the mains, using some external circuitry (PLL like a 4046).
CatalinaWOW:
--- Quote from: Yansi on January 13, 2019, 09:25:33 pm ---Forget analog filters. It won't be precise and stable enough, not really something botched up from a quad opamp package. But still, I haven't noticed you specifying the purpose of this 3ph generator, so hard to judge if that would suffice or not.
Even if you could produce three sine waves 120 degree apart using few opamps, whats your plan of amplification up to 220Vac? This analog solution just does not make much sense. The digital route is definitely easier one.
You may probably find MC3PHAC integrated circuit. Which if I remember correctly is some preprogrammed 8bit MCU or what. Very expensive, probably very obsolete too. But can produce 3ph PWM to drive a power stage, and probably could be frequency locked on the mains, using some external circuitry (PLL like a 4046).
--- End quote ---
This all hinges on what the purpose and requirements are. Stated requirements are 220 V AC single phase in, 220 V AC three phase out with 20 mA supplied and phase synchronization.
An analog solution that achieved fractional degree phase alignment while supplying 220 +/- 1% output voltage would be complex and unwieldy at best. Digital approaches are likely to be far better, but I can make no meaningful recommendations on IC's.
One that achieves phase within a few degrees of correct with outputs set at a nominal round 170 VAC might be suitable to purpose and is almost trivially easy to implement.
It all depends on what the "real" requirements are. These dark corners of specifications are always where confusion lies and frequently leads to overdesigns, or underperforming designs.
Yansi:
I have asked few times here, what the real purpose and requirements are. Still waiting for the response. :-+
T3sl4co1l:
--- Quote from: TimFox on January 13, 2019, 02:13:21 am ---Google “Scott-T Transformer”.
--- End quote ---
Not from single phase though!
Also, not the US's "two phase" or "split phase", because the phase shift there is 180 degrees. In linear algebra terms, it's linearly dependent.
The traditional methods, as mentioned, are a rotary phase converter (uses a spinning mass to generate the rotating phase sequence), or a VFD (synthesizes phases directly, with a controller).
If the load is a motor, the third phase can be generated in situ (with a capacitor), if you don't mind that the starting torque is low and the maximum output is reduced (about half, I think?).
If the load is a rectifier (lots of industrial equipment, e.g., VFD, welder, etc.), it doesn't much matter how many phases it's powered by, but you may need more filter capacitance on the supply, and the power factor will be poor, which is a big pain when it comes to the already low capacity of US outlets.
Tim
Yansi:
I am not sure, but I think most (if not all) commercially available rotary converters will not have the output synced to the mains input and will provide slightly lower frequency? (unlikely to have both synchronous motor and synchronous generator inside).
But I am not sure, how these are really made in the US, as we do not have to deal with this garbage in central EU. (3ph present in almost if not every household).
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version