Page 14 of 28 FirstFirst ... 4121314151624 ... LastLast
Results 131 to 140 of 273

Thread: 1000w smps based on LUDO3232

  1. #131
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    Hello Eusebio,
    I am sorry to say that the spacing in various parts of the pcb layout is not so good. The spacing between the traces regarding high voltages are too small. These should be around 3mm apart. These include the mains input and also the 300 volt rails.

    If you want to remedy this problem you can use a sharp knife or a broken hacksaw blade and ruler and scrape away some of the traces to widen the clearance for at least 2mm . You must also cover that fuse because it is very near the heat sink. You should also clean the underside of the pcb from rosin (flux) with solvent like cellulose thinner or acetone. It is very important to keep the pcb clean as traces can easily leak with each other and you end up in a catastrophy, not to mention getting yourself electrocuted.

    When all is ready you must use some lacquer spray on the traces to seal out moisture. I use normal transparent cellulose lacquer spray found in hardware stores.
    Do not forget that when everything is fitted in the amplifier dust tend to get in the box with the fan running and moisture and dust tend to short out the traces of the pcb. You must protect the pcb because of this.

    Regarding the delay circuit it does not make any difference which circuit you use as long as it works properly with adequate timing.

    The schematics you are following are more or less the same apart from one of them having feedback and more capacitance in the output.
    In my schematic the 500 ohm preset adjust the dead time of the oscillator. You can put a fixed resistor once you find the right value.
    My smps dead time is 1uS. R7 attached to pin 9 on my schematic will not allow you to go down below 1.5uS so you may need to change it to 820k instead. Be careful but if you do not have an oscilloscope do not touch it as you cannot see the dead time. You can drive the oscillator pcb separately and set the dead time first and see that all is correct before you power up the main pcb.

    Lastly you need some support in the center of the pcb as this may bend with weight and also while testing and the underside may touch the chassis of the amplifier box

    Please be careful while testing and powering up the smps.

    Regards Silvio.

  2. #132
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    Quote Originally Posted by eusebio View Post
    I followed the design below just do not use ic 555 which changes for a pic, as for the protection by sensing in the primary stage I have that doubt using trimmer of 20k 0 500ohmsAttachment 6563Attachment 6564
    For the trimmer you can use what ever you like between 500 ohms and 22K. In my case I used 500 ohms because the voltage across it is only 5v so the current is 10mA and power dissipation is 50mW. The trimmer is rated for 250mW. For larger value trimmer this will be less current and wattage.

    The frequency of operation of my smps is 62Khz. I used 0.5mm wire so frequency cannot go beyond 68Khz due to skin dept.

    Silvio

  3. #133

    Protection problem

    Hi,
    here is my second attempt to 1000w smps.It works at 85khz ,output is +-80v DC and will power 4 channel class D amplifiers. One channel is in the picture. The smps works good, at idle only transformer get a little warm ,anything else is cold. But I have problem with current protection, cant start smps with protection without a bulb in serial with input voltage (230 AC). The protection trip every time with or without load on secondary side if I connect smps direct to mains.Without protection I can get 5A current at output with 10V dropout and not much heating of any component.The current trafo is toroid with 50 turns for secondary and 1 turn for primary,the rest components are the same value as on schematic .Can anybody tell me how to fix that problem?


    Regard
    zoky 2
    Attached Images Attached Images

  4. #134
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    @Zoky2

    Dear Zoky, If the schematic that you followed is the one found here of LUDO 3232 then the turns for the overload trafo must be 22 turns and not 50. The load resistor is to be 10 ohms 1 watt.
    Once you start up the smps you should load it gradually to full power with resistive load like heater or bulbs etc until you arrive to a load of 7 or 8 amps. You should adjust the overload preset gradually until the smps trips on overload at the wanted output current. I can also see that the output inductor is a bit large and this will increase your voltage drop at the output.

    I hope that helps

    Regards Silvio.

  5. #135
    hello silvio after a short break I made the adjustments that you had recommended me, currently the source is working with 65khz and igbt G4pc50U trafo delivering 78 volts symmetric attached photos. As for the protection is working well use resistance to sense of 22ohms 1w and serca 30 turns in iron powder core. use resistive load of 1500w microwave resistors protection set in 17ampIMG-20180318-WA0040.jpeg

  6. #136
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    Hello Eusebio,

    I can see that the you set the trip current to 17 amps. I do not know if the voltage on the meter is with the smps fully loaded or on idle.
    You must measure the output voltage while the smps is loaded to see what is the power that you are actually absorbing.

    Power = volt X amps.

    My smps drops from 160v (80-0-80) to 140v at a load of 9amps.(1260W) (The trip current is set to 10amps. around 1400w)

    I am not using output inductors and ripple voltage is 4v peak to peak at full load.

    I gave you my results for you to make some comparison.

    Regards Silvio

  7. #137
    Hi
    how many turns do i need for an etd49 primary and secondary? I need a secondary voltage at 80V and how many auxilary turns do i need?Sorry for my bad english!!!

  8. #138
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    Hello Booker,

    You need to give more information about your transformer as follows:-

    What is the core material (example PC40, N87, N27 etc)?
    What frequency are you going to run your smps
    What topology are you using (half bridge, full bridge etc)?
    What is your nominal grid voltage (220, 230, 110, 120)?
    Is the smps regulated or not?
    What power are you looking for?
    Purpose of smps audio or something else?

    Regards

    Sivlio
    Last edited by Silvio; 03-23-2018 at 06:23 PM.

  9. #139
    Its your smps from this thread,core material is N87 ,the nominal voltage is 230V and it is for audio. I think for Primary 18 turns and Secondary 9-0-9 turns is this right?

  10. #140
    diysmps Senior Member Silvio's Avatar
    Join Date
    Apr 2015
    Location
    Malta
    Posts
    495
    Blog Entries
    9
    @Booker

    Yes with those turns you will get a little less than 80v at 230v but if the input voltage is around 240v then it will peak 80v.
    The volts per turn ratio is 9.4v per turn.

    Another combination you can use is to wind the primary with 20 turns the secondary with 10-0-10 turns this way at 230v you will have a peak voltage of 325vdc dividing this by 2 will get a primary voltage on the Half bridge of 162v so to get the volts per turn this time we divide 162v by the number of primary turns (20) we get 8.1v per turn. so for secondary 8.1 x 10 we get 81v.

    Well it all depends on what your amplifier can take as maximum voltage.

    The example above will give you a good idea how to play a little with turns. However do not go below 18 turns and more than 22 turns for primary windings. The turns described are suitable for a switching frequency of 60 to 65Khz

    In my smps I finally removed the output inductors and got less voltage drop at load. I also added a 1uf polypropylene caps across each output to center ground. This helped further more with filtering the noise in the output.

    Regards Silvio
    Last edited by Silvio; 03-23-2018 at 08:26 PM.

Similar Threads

  1. 1000W mosfet amplifers
    By MicrosiM in forum Mosfets
    Replies: 7
    Last Post: 09-23-2015, 11:22 AM
  2. Replies: 8
    Last Post: 11-17-2014, 01:53 PM
  3. IRS2092 2x500W/1000W BTL
    By b_force in forum Class D
    Replies: 11
    Last Post: 05-13-2013, 04:54 AM
  4. PiC based flyback SMPS
    By nigelwright in forum diysmps
    Replies: 0
    Last Post: 10-29-2012, 02:03 PM
  5. Quasar 1000w smps
    By tvicol in forum diysmps
    Replies: 21
    Last Post: 02-17-2011, 03:08 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •