Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Help me with 3 phase to DC converter design

Status
Not open for further replies.
M

Mayer_DEV

Newbie level 3
Joined
Mar 8, 2009
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Jerusalem, Israel
Activity points
1,313
Hello,

Working on design - inverter for 3 phase induced motor 380VAC x 3
I am using IGBT module (rectifier + 6 transistor) that convert the 3 phase to ~537.4VDC = 380 x 1.414

I need from that voltage 537.4VDC create lower voltage for the control section - 15V + 3.3V Isolated

one option is to use flyback trasnformer with multioutput with isolation

other option is to take one of the phase (220VAC) and rectifier it and create DC voltage

My input to system is just 3 wire (L1,L2,L3) only the 3 phase
to recticifier the 220VAC I need neutral (which is not in my system)

How can I "create" neutral from the 3 phase - or I must use neutarl form the socket (which I havn't -or not connected)


Thanks for your time

Mayer
 

Re: 3 phase to DC converter

It's not clear why you want to connect neutral. Industry standard inverters are mostly deriving internal auxilary supplies from the DC bus voltage by a DC/DC converter.

Are you using a switched mode AC to DC converter or a three phase rectifier bridge? A switched mode converter ("active front end") would be useful to increase the power factor, but is rarely used for standard motor inverters.
 

Re: 3 phase to DC converter

Use two 220v-> 12V transformers, wire their primaries in series and put their secondaries in series, if you have got the connections round the right way you should have a 440 - 24V transformer ( or buy one!), wire it phase to phase.
Frank
 

Re: 3 phase to DC converter

I am using IGBT module (3 phase Rectifier bridge + 6 transistors)
Not using switching mode

As you said - I am going to design flyback DC\DC converter

My first thought was to take one phase and neutral because most of the design (for flyback converter) that I saw was with input of 85VAC - 265VAC.

Now I need to find an isolated transformer with mutiple output for 537.4VDC to 15VDC and isolated 3.3VDC

IS there "on the shelf" transformer for such input (537.4VDC) or I need to design transformer with a manufacturer?
 

Re: 3 phase to DC converter

You can't "create a neutral" without a transformer and it's usually unwanted to connect the neutral if it's not needed otherwise in the machine. At least noone would accept this requirement in an industrial product. As reported in previous edaboard threads, the 400V AC input converters are often using topologies like two-switch forward or flyback to limit the switch rating to a single DC bus voltage. A half-bridge forward converter would be an option to reduce also the transformer voltage.

Switched mode power supplies with 400V AC input are a standard in automation, by the way.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top