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Ac frequency converter

  1. Jan 5, 2010 #1
    Can someone give me a circuit diagram i can use to change the frequency of AC current?
  2. jcsd
  3. Jan 5, 2010 #2
    Are you interested in changing 50 or 60 Hz power to another frequency, or in changing RF frequency signals, like 1.0 MHz to 455 kHz?
    Bob S
  4. Jan 5, 2010 #3
    One option is to get a voltage regulator to convert AC to DC. This voltage can then be increased or decreased by using either an op-amp or voltage divider. This adjusted voltage then goes to a Voltage Controlled Oscillator. This produces a certain frequency depending on the voltage going into the VCO. When you adjust the voltage for VCO input it just depends on the VCO parameters and your desired frequency.
  5. Jan 6, 2010 #4
    I mean like 50 - 60 hz range.....

    Sazhi my knowledge of electronics is very basic, can you please elaborate a bit?
  6. Jan 6, 2010 #5
    I think the basic idea is to rectify it and then use an inverter to change it back to ac right? I don't really get how an inverter works can some1 give me a link to the working principle?
  7. Jan 6, 2010 #6
    Why do you want to do this?
    What frequency do you want to change from / to?
    What voltage and current will you be using?
  8. Jan 6, 2010 #7
    Idoubt, that's right, we can rectify to get dc and use an inverter to get back ac. The VCO is basically an inverter. When you say 50 - 60 Hz it sounds like we might be dealing with power from an outlet. If that's the case, the IC that I know of that has VCO won't be able to take that much power.

    But if you are doing something with low power I'll include the link for that IC.


    Figures 1 and 5 will help you set up the VCO. There's things in figure 1 you don't need to worry about, just as long as it's connecting to the VCO, this chip has other functions we won't need for this application.

    I have a link for an inverter that can take higher loads, I'm assuming this is for 60 Hz output, but this could probably be changed with different capacitors.


    Hope this helps
  9. Jan 6, 2010 #8
    Well I want to know the theoretical side more than the practical. I want to know how a dc current is converted back into an ac, and how the frequency of that ac is controlled. I'm thinking mains voltage
  10. Jan 7, 2010 #9
    I don't know the theory behind it. But now I'm curious and look forward to someone else's response.
  11. Jan 8, 2010 #10
    No, I don't know of a simple schematic for this. Even if I delivered one, you would still need some specialized parts, like custom transformers.

    All of the schemes I've seen involve rectifying one side (i.e. 50Hz) to produce what's termed a link voltage (approximately DC). That in turn goes through an inverter to produce the new frequency.
    For large systems, the 12-pulse rectifier is used to change three phase AC to DC. At that point, a 12-pulse inverter can change it's frequency or simply turn it back into the original AC (which is good for DC power transmission).

    On a small scale, you're generally better off to get your equipment modified. Most televisions, radios, and computers are happy running at either frequency, but may have difficulty with an associated change in line voltage (i.e. 100V in Japan vs 115 in USA). For these occasions, small transformers are available that supply a moderate boost or drop in voltage, whichever the case may be.

    When operating motorized equipment, the change in frequency is more of a nuisance. The motors found in hand drills and vacuum cleaners don't mind the change, but the types found in most other appliances can be damaged.

    Going from the US to Japan, a slight increase in the applied voltage (i.e. 5V) is what worked best for me when shipping pump motors.
    I would not be confident that any reconfiguration would make a Japanese 50Hz appliance safe in the USA.

    As for the EU, most electronic equipment can be reconfigured by a switch, or is already compliant. Check the label.

    As for transporting appliances between the USA / Japan to EU / Australia, forget it. It's not practical.

    I hope this helps a bit,

    - Mike
  12. Jan 10, 2010 #11
    Yea I remember hearing somewhere that if you use some tape recorders at a higher freq than specified, it will run faster making songs sound as if it was fast forwarded.
  13. Jan 10, 2010 #12

    On older tape machines, the capstan motor used the line frequency for reference, hence the playback speed varies with line frequency. The same thing happens with the simpler record players.

    As I recall the Beatles suffered from this when on tour.

  14. Apr 23, 2010 #13
    why cant you go for an CYCLOCONVERTER wher thyristors are triggered according to the output frequency needed
  15. Apr 29, 2010 #14
    It is not so easy to convert 50Hz to 60Hz,
    First of all you need to convert your incoming AC to DC and then by using IGBT modules (Driving them by PWM modulation) invert the DC to AC again. This is UPS topology and for frequency converter the topology is same. you only need to play with the frequency parameters on your controlling board.
  16. Apr 29, 2010 #15
    CYCLOCONVERTER is an AC TO AC CONVERTER why will u again converter to DC n again to AC?
  17. Apr 29, 2010 #16
    Actually, i do not have so much knowledge about the Cycloconverter but i know this system is mainly use in controlling speed of AC motor. Also it is not easy to find into the market.
    The system i described above is more common one.
  18. Apr 29, 2010 #17
    it not so complicated bcoz ur sayin freq is 50 hz which u want to step up to 60 hz so this sytem has 2 types mid point and bridge type connections by applying gate pulse to thyristor u can make it. i got two simple circuit diagrams where u can understand what actually happenc in cyccon

    Attached Files:

  19. May 7, 2010 #18
    firstly rectifier, and then inverter
  20. May 13, 2010 #19
    Go old school with it, get a motor and a generator, coupled with a 1:1.2 pulley ratio
  21. May 14, 2010 #20
    use rectifiers..E.G. bridge rectifier
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