Complete circuitry of active KKM and charger for 3 kW UPS

    Part 1
    Part 2
    Part 3
    Part 4.1
    Part 4.2
    Part 5
    Part 6

    As usual, a little lyrics ... Comrades! Those who take and publish my articles, materials and other nishtyaki - please indicate the real author and the source.

    I think everyone perfectly understands that I can sell my projects corny or make a jump for coins and they will buy it all, but I do not want to do it. I want to give people good, chewed-up projects and training materials that you will not find anywhere else, much less receive assistance in assembling and consulting for many hours. I upload the sources of all files absolutely free of charge and offer several options in order to save your money!

    For all my efforts, I do not require any gratitude, it is enough for me that you read and you like my articles my work)) But please - do not steal the material and do not assign authorship to them! So that administrators of third-party sites do not write to me and do not ask me to delete my own articles, stating that I am not the author, but Vasily Petrovich Zalupkin, who the real author published these articles on his site! And I don’t care that 2 months later ...

    I hope those who acted like this will hear me and be more honest, not even with me, but with themselves. Thanks for attention!))

    After the publication of articles No. 5 and No. 6 from my UPS cycle, I decided to check them in the hardware. It is worth remembering that all the articles in the cycle adapted for self-assembly versions of my commercial projects, so I consider it blasphemous to give naked without confirmation . I can say right away - the result was many times worse than expected! Need to recycle!

    I also ask you to pay attention that in this article I am already laying out a diagram of a fully finished device! They went to it : an active power corrector + power board of the charger + control board of the charger + standby power circuit (from part 3 ).

    Another very important point: all who have already bought from me KIT kits for assembling the UPS received this particular circuitry option! So, don't worry - you got the best product!

    Circuitry of a powerful charger with an active power factor corrector

    It is worth noting that the option from part 5 and part 6 is also working and takes place at least because it turned out to be 20% cheaper, but this is, however, a reason!

    I will not torment and immediately show the final version of the circuitry, which I have obtained and meets all the previously stated requirements, and most importantly, I have worked stably under 110-120% load for 3 weeks . Therefore, with a clear conscience, I present to you the final version:

    Figure 1 - Scheme of the implementation of standby power, familiar from Part 3

    Figure 2 - Control board with a generator, drivers and protections

    Figure 3 - Power section of the charger

    Figure 4 - Scheme of an active power factor corrector

    Figure 5 - A single board that contains all of the above parts, dimensions came out 300x200 mm with a copper thickness of 105 microns (Rezonit will do this)

    Figure 6 - A little visualization, the top layer (Top Layer)

    Download the device project in Altium Designer 15

    Description of problems and methods for solving them

    And so I put together a power corrector (hereinafter KKM) according to the scheme from a datasheet based on L6561 , the result of this decision made me very happy. Although I used to assemble schematics on it, but at powers up to 500 W , I was pleasantly surprised that the controller proved to be excellent in the 3000 W version as well! But you understand very well - if I redid something, then the output was a shit device with unsatisfactory characteristics, but I don’t like this at all! What is the trouble:

    1) The theoretical calculation of the output capacitance (electrolyte) turned out to be far from reality. Therefore, it was decided to increase the capacitance from 220 μF to 440 μF.

    2) The KKM throttle designed for a frequency of 60 kHz turned out to be my failure ... The PWM frequency at the output of L6561 varies from 20 to 150 kHz and this is not programmed in any way. I simply forgot to take into account that this controller regulates how TM, what it can be read in LH on it or on the Kompel website.

    3) The IGBT key was not able to work at such frequencies, after 80 kHz terrible switching losses / dynamic began, there was only one option for this - to use a powerful field-effect transistor and the choice fell on the FCH35N60. This is a key on 35A and 600V, capable of working up to 200 kHz - I did not check it above.

    4) I understood the frequency at which the inductor needs to be calculated, only after the results have been carried out, I don’t understand this by the datasheet - simply because this controller is positioned up to 300 watts. The frequency chosen is 110 kHz.

    5) I would like to point out as a separate paragraph that, by increasing the frequency and a new key, I managed to fit the throttle on one single core made of -52 material with dimensions 57x35x25 mm!

    And these are problems only with KKM! After solving them, the corrector acquired a very diligent appearance, in the range 165-235V AC after the diode bridge, the temperature does not rise above 65 degrees. In the range of 85-280V AC, the temperature never reached more than 115 degrees! This is victory!))

    Knowledge and experience gained (for me personally):

    - The microcircuit is suitable up to powers of about 5-6 kW, that is, for any single-phase solution;
    - The output capacitance must be selected from the calculation of 125 microfarads per 1 kW of power;
    - On a winding current shape control (ZDC) one turn is enough;
    - In KKM there is no place for IGBT transistors

    Handling Charger Errors

    My main mistake was topology . The slanting bridge is the topology I adore! But alas, I refused it ... Her trouble was that with prolonged operation at rated load and in overload mode, the efficiency dropped to an insignificant 80-82%! I had a dilemma - the efficiency of the “oblique bridge” at loads up to 60-80% and rare crossings up to 100% was about 92%, which made me happy. The repeatability of this topology also bribes me, but the low efficiency during long-term operation of 100-120% of the nominal value was straining. Yes, in this mode, the UPS operates soooo rarely, because 60-70% loaded UPS is considered a good tone. Only given my experience in commercial projects, I realized one thing - it is necessary to make sure that even a complete moron could not kill the device! After that, everything became obvious -full bridge! (H-bridge).

    I think everything is very clear here - I had to essentially develop a new device and run it in, which is why the article was delayed.

    Experience gained by me from this work:

    1) You can use the “Diagonal Bridge” if you are not going to rape the UPS and you have to power the server rack from it. That is, operate in soft mode and without prolonged overloads;
    2) We use the N-bridge if you are an inadequate maniac and just burn with the desire to power a 3.3 kW induction motor 24/7 from the UPS! Well, either we decided to cook non-stop metal sheets from 10 mm))) In general, the topology for serious guys!
    3) The topology must be selected according to your needs and tasks
    4) I did not see the meaning of galvanic isolation in these parts
    5) 48V is acceptable for 3-4 kW, but it is better to raise the DC bus voltage to at least 96-120V (8-10 small batteries 17 or 27 A * h), ideally 240V (20 small batteries of 12 A * h)

    Calculation of transformer and chokes

    I told how to make a transformer and count in part 2, I advise refreshing the memory to those who decide to assemble this circuit. There, just on the example of the N-bridge, the article is written that will please you))

    Figure 7 - Calculation of the coil data of the 390-58V transformer for the charger

    Figure 8 - Calculation of the output inductor

    Figure 9 - Calculation of the KKM power inductor (second winding 1 turn)


    That’s probably all, we’re studying a new solution, lighting up and asking questions that have arisen - as usual I will try to answer and help them!))

    Just the same news for those who did not get the KIT sets - the new arrival of 50 sets will take place on February 25-26 ! As before, you can purchase: boards, stitched and soldered microcontrollers STM32, as well as a complete set with accessories and radiators!

    By the way, the video has already been shot, it remains only to process it to a more or less adequate state)) If you want to help me, write me an email or in VK!

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