Hi,
For me a three phase SMPS for a total of less than 12W output power seems to be overkill.
Why 3 phase?
Klaus
As the power is very low (13W) then then use two of the three phases. There is absolutely no reason to use all three phases. The input/output MUST be transformer isolated as what was the neutral is now 230V and any RFI capacitors must have adequate working voltage.
Frank
Hi,
While you need the voltage signal of all three phases, I see no need for a three phase power supply.Why?
10W for a power meter is huge. It's about 90 kWh per year.
Klaus
Hi,
O.k. GSM clarifies the 10W,
But i'd go for three phase SMPS if the power is 1500W or more ... But not with 10W.
What is the benefit? Why do you want a three phase SMPS?
Klaus
That's the point. This makes sense.so if one of them drops, the meter keeps working.
No one of us can tell you. You should find this in your project specifications.I have a question about this, first: what is the danger if the meter stops working if one of phases fails? I think I do not need to measure anything if not all the 3 phases are connected, is not it?
No one of us can tell you. You should find this in your project specifications.
Klaus
That would need a flyback supply that can run off up to 650v dc.I think trees nailed it in post 6. 3 phase bridge rectifier no neutral needed, it will work on Y or delta power. Then use a flyback and see Power integrations for app notes.
So you have three alternatives (perhaps?). The easiest is to use the neutral and use a single diode from each live phase to fire up the DC/DC converter. Also this gives you a voltage monitoring point for each phase within your piece of kit. One other way is to use phase to phase voltage without a neutral. For this you need three single phase transformers (415V-> 12V) and common one terminal of each to give you a LV neutral and a diode from each transformer to give you your + DC volts. The other way is to establish a local "neutral". String three capacitors from phase to the artificial neutral point. They will drop a voltage so their value needs to be calculated.
Frank
Depends on where you are.but in such case, the input voltage of DC/DC converter will be designed to be 514 volts Dc, right?
Depends on where you are.
Nominal voltage in Australia is 240v with 215v to 265v supply range.
Phase to phase 1.72 times that up to 456v
Peak rectified 1.414 times that up to a really scary 645v dc.
Even at exactly 230 volts is 396 phase to phase and 559v peak.
When we designed an ARM network at Iris Systems Inc in mid-90's we only needed a watt of power and this included charging a large cap for Tx high power ISM microwave radio on demand any minute of the day. So all we needed was a ceramic hybrid with large R's and zener diode bridge for DC. THis was converted to several voltages for MC6805, UHF Rx/Tx , IR 2-way comm diag port and IR power disc rotation detector.
In your case, your power demand seems to be far greater.
So just choose the 3 phase transformer suggested and combine with a 3phase bridge rectifier.
T1 3P AC-DC converter, 220V - 12V/5V Sanki DB-12CY220
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?