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  1. Replies
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    Closed: Re: L1 and C1 value for EMI filter design ?

    if you want a general idea, (theres no real formulae for it), then think of your power level, ...says its a 60w flyback...then check out app notes for 60w flybacks and see what they are using....or...
  2. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    For a 56kg tethered drone consuming 12.5kW and using an 800vdc feed from the ground based power supply…what voltage would you say was chosen for feeding to the BLDC motor inverters?
    (i was told it...
  3. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks, this is a good point, because I can imagine that if there are say eight or so open-loop synchronous Buck converters supplying the same load in parallel…then do you believe there can be a...
  4. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks, no testing as yet...though i believe that we will be clewar of current hogging problems with this parallel open loop Buck.
    I stepped the load from full to zero and VV in the sim and it...
  5. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    The following looks good for high input voltage…..its two LLC converters in series, but they share the one transformer and the one resonant inductor....
  6. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    yes the sim works, but there are some ~3ns spikes in the sync fet up to 20A, i presume this could be a simulator thing though...maybe the internal diode in the sync fet is very slow.
    I put some...
  7. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Hi
    Thanks, the attached (schem and ltspirce sim) is a Dual Buck with the last stage with a sync fet and at 50kHz.
    I added a comparator to the COMP pin of the controller …this being done so that...
  8. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i appreciate they wont ever generate back, and will always be running significant power, but wondered what generally the total power range (ie percentage of max range) is likely to be whilst...
  9. Closed: Re: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation ne

    Thanks yes, the Dual cascaded Buck…all from one controller…..this looks a good shot. No problems with control loops fighting.
    I could only do it from 800v in LTspice because theres no 1kv diodes in...
  10. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks,
    If a drone is up in the sky, and is then brought down to land.......then whilst it is coming down, what power are the motors running at?.....roughly what percentage of full power?
    I assume...
  11. Closed: LLC converter vs Dual cascaded Buck….1000V to 48V at 500W output…no isolation needed

    Hi,
    Do you agree that the LLC converter would be more efficient for the above case?
    Consider synchronous rectifiers in each case.
    The Buck would be a Dual cascaded Buck so that Duty cycle was...
  12. Replies
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    Closed: SMPS for 5000W can be a Full Bridge

    On page 9 of the book “Power supply design, Volume 1 Control” by Dr Ridley, he states that a Full Bridge converter is good for power levels from 200w to over 5000w.
    Most places where I have worked...
  13. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, we are looking for a offtheshelf 200w-500w BLDC motor which takes Vin of 400V or more but cannot find one, do you know why this is?
    There are millions with voltages up to 48V, but almost...
  14. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i am wondering if it can be done the other way concerning the motors.......ie, high voltage and lower current?

    - - - Updated - - -

    Hi
    Would you agree that the old addage that “Motor...
  15. Replies
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    946

    Closed: Re: convert voltage control to current control

    We have discussed here how Current mode control can’t be used in a half bridge SMPS.
    However, the following document states that a “Current Doubler rectifier “ can be used with a Half Bridge...
  16. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, no we didnt, but we will parallel them.
  17. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, we will end up using back-to-back power FETs with isolated drive due to the total 32A of current. We will parallel them.

    What worries us is that I can see that if our zero-cross isnt pin...
  18. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    Thanks,
    Ill try the "common mode" test
  19. Closed: Re: Voltage input to BLDC inverters on tethered drone?

    Thanks, i suppose there is no power supply on the "tethered drone"?...just the BLDC inverters...which must us high voltage IGBTs?....

    Maybe somne just have a rectifier bridge and smoother to feed...
  20. Closed: Voltage input to BLDC inverters on tethered drone?

    Hi,
    Regarding tethered drones such as the LIGH-T 4, which is rated at 1.2kW….
    https://elistair.com/ligh-t-tethered-station-for-drone/

    Do you know what voltage the BLDC motor inverters are ...
  21. Closed: Re: Need to reduce drain voltage spike in LM5019 Buck converter

    Thanks, it seems a little odd that in the datasheet "ABS MAX's" it says the SW pin should be no higher than "vin+0.3v".......whereas the vin pin can be up to 100v......so why cant the SW pin be...
  22. Closed: Need to reduce drain voltage spike in LM5019 Buck converter

    Hi,
    We are using the LM5019 for a Buck converter
    Vin = 60V
    Vout = 12V
    Iout = 7mA

    We notice a spike on the LM5019 drain voltage of 20V in magnitude...as in the attached. This surprises us, as...
  23. Closed: Re: ZMR330: 3V3 Linear regulator needs diode connected cathode to input voltage?

    Thanks, i mean a diode connected anode to output, cathode to input...
    in the old days, such a diode was always needed to protect the regulator in those cases wherever vout gets bigger than vin.
  24. Closed: ZMR330: 3V3 Linear regulator needs diode connected cathode to input voltage?

    Hi,
    Question as per title.

    ZMR330 datasheet
    https://www.diodes.com/assets/Datasheets/ZMRSERIES.pdf

    ..the datasheet doesnt say such a diode is needed. Would we need one.

    We are using it...
  25. Closed: Re: Resistor at input to high side current monitor IC

    Thanks yes,
    We have Rsense = 0R75, RA=1k and RB=3k3.

    I made RP=43k and readings (voltage on RB) were badly inaccurate.
    Now that we have RP=RA, the readings are good....

    ..the problem is, as...
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