Sonsivri

is it possible to convert 220V 60 hz to 220 V 50 hz? any one have any circuit diagram? or any document or link about this conversion??

Need more input here.  How much current do you need?  3 uA or 30 Amps? 

A Variable Frequency Drive will do the job if you want to run a motor.

Yeah a little bit more information about the usage would be very good.

As oldvan said you can use a variable frequency drive. If you need it to
drive a switching power supply you simply won't need it because they
mostly are built to work from 100-250V (45-70Hz). So there is no need then.

You can in many cases use 60 Hz electronics equipment with 50 Hz, but a few things are worth noting:
* If the device outright depends on mains frequency, for example some turntables and electromechanical clock, they will run slower
* If the power supply uses an "old-fashioned" transformer or a motor, which run on the mains frequency, it will get hotter on 60 Hz than on 60 Hz. This may be a problem, or even a fire hazard!
* Of course, the mains voltage is important: USA: 115 V, Europe: 220-230 V, elsewhere: I have seen various country-specific voltages from 100 to 240 V

Also, I agree with DarkClover's and oldvan's comments. We all are just guessing when we don't know what you try to do exactly!

-tedz

tedz actually I want this for my 50 Hz supported 2KVA online UPS. I have a generator of 60 Hz and my main supply is 230V 50 Hz. Thats why I need this because it is a bit expensive for me to buy a new 2 KVA online UPS. :-[. My UPS gone to my PC. If u have have some idea or document about this ? please help me..................   

Perhaps easiest would be to contact the UPS' manufacturer and inquire if it will
function OK on 60 Hz.  Otherwise, maybe you could adjust the generator's RPMs
down to achieve 50 Hz output?

I ve already contacted but they said negativeand they could not make a single UPS for me. My generator frequency is unchangeable. I ve here about "CYCLOCONVERTER" but I dont have any idea about this.

A cycloconverter is an easy frequency converter.
It rectifies an incoming AC source of any frequency. Then, with the help of thyristors, the DC voltage
is converted into another (almost) AC voltage with a given frequency.
But instead of a cyclonconverter you should use the improved version named tap converter.

If you don't want to build one you can use a very very inconvenient method.
Use any strong enough external PC power supply (made for running on 60Hz).
Then put all the 12V lines together to one but use for every single line a
high output low drop diode in series to prevent from damage.
After you have done this, use a simple 12V-to-230V(50Hz) car power supply with
true sinus-wave output and *TADAAA* now you have a good enough
supply for the UPS (maybe ;))
...but thats isn't a really good method!


Greets DarkClover

A variable frequency drive like the following:
http://www.factorymation.com/s.nl/it.A/id.5577/.f?category=15367
Could do the trick, but is not a cheap cure.

Perhaps just a decent battery charger circuit and bypass the one in the
one built into the UPS?  Would likely be more efficient overall than the
other ideas.

Perhaps mount an alternator to the generator's engine and off it goes?

DarkClover@ I am insterested about cycloconverter but your inconvenient method is also inconvenient for me.
Oldvan@ I am searching for an efficient circuit, not for commercial product.

Another method (maybe inconvenient) would be to convert the 60 Hz to DC and then use a full-bridge driven by microcontroller with SPWM to generate an AC 50 Hz pure sine output.

Yeah that's a variable-frequency drive. I don't know but wouldn't it be difficult to build it
for such high energy consumption ? You need very big MOSFET and active cooling.
However, i think the basic idea in converting to DC and then transforming it to 50Hz
is the cheapest DIY way to get to the goal.

tahmed can u give more information or links or pdf??

To convert the source to DC you just need an ordinary rectifier. But be sure you design it
for those 2KVA of your UPS. That's the rule for everything on this circuit. It's better to overdo it a little bit instead of destroying all.
Here is a good example (picture) how such a thing work: RECTIFIER (http://eratechsolutions.com/electrical.html)

And for the full-bridge, there are thousands of examples out the net but 99% are in inverse direction e.g. drive
a DC motor instead of generating AC, which is just the oposite way to use this device. However I found something
interesting on the net: DSP controlled online UPS (http://pemclab.cn.nctu.edu.tw/W3news/研究成果/TR-UP06:DSP-controlled%202KVA%20on-line%20UPS/index.htm)
if it's to complicated you can use the technology of a cycloconverter but build it just for one line
and not all three (or more). It works the same way.
Or have a look at brushless-motor driver for RC-helicopters or airplanes. It's also the same thing just
for smaller devices and it has 3 phases (which shouldn't be the problem)

and for the PWM have a look at Wikipedia: PWM wiki (http://en.wikipedia.org/wiki/Pulse-width_modulation)
The first picture is exactly what you want to generate.


How all that stuff works:
First you get the 60Hz AC and convert it to almost DC with the rectifier. Then it will be filtered
with some capacitors and inductors to eliminate the high-frequency peaks.
After that the current flows into the DC-AC-converter. The bridge-circuit driven by PWM (see wiki)
will convert the DC current to "dirty" AC of 50Hz and of course 220V.
If you want a proper AC you have to add some filters to the output which smooth the output wave
but I don't think that's really neccessary.


Greets DarkClover

In general 50Hz supplies are compatible with 60Hz, but not vice versa, since 60Hz transformers may saturate on 50Hz.  I don't think think this applies to AC motors, though.