Difference in "PWM" controllers

garlicgarlic Posts: 43Solar Expert
I had read somewhere yesterday someone stating that the Xantrex
C series controllers were not "true" PWM controllers.I was wondering
then If someone could please explain the difference in technology (if any)
between say a C35 and a Prostar 30 as far as how they apply current?
Are there any substantial advantages or just a different way to get to
the same destination?Not that this has any major bearing on what my
system plans are.I'm just curious as to how they might be different.

Thanks,

garlic.

Comments

  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Difference in "PWM" controllers

    they are pwm controllers. i don't know of any basic differences. if you think of what was really said about it and where please tell us as i'd certainly be curious who said what.
  • garlicgarlic Posts: 43Solar Expert
    Re: Difference in "PWM" controllers

    I hope I wasn't taking it out of context,though I don't believe I was:

    http://www.solar-guppy.com/forum/general-charge-controller-suitable-for-jacobs-wind-turbine-t207.html
    An FYI

    the Xantrex C40/C60 is not a true pwm contoller , it lacks the inductor part for that. It is really an On/OFF controller.

    I just wanted to make sure I understood the technology correctly

    Thanks,

    Garlic
  • mike95490mike95490 Posts: 7,901Solar Expert ✭✭✭✭
    Re: Difference in "PWM" controllers

    I think there was a typo in that message.

    A simple FET can perform PWM control (Pulse width modulation) and needs no inductor.

    A MPPT controller needs inductors, so it can perform the voltage downconversion.

    The C-xx series is all PWM controlers
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Posts: 27,883Super Moderators, Administrators admin
    Re: Difference in "PWM" controllers

    That was about 9 years ago... Not answering for Solar Guppy, but today, as Mike says, we call PWM as "on/off" controllers.

    And controllers that use inductors are MPPT (Maximum Power Point Tracking) which, usually inside have a switch mode power supply that is Buck type down converter. Which has the inductors to allow the MPPT/Buck Mode type charge controllers to efficiently take high voltage / low current and down convert to lower voltage / higher current for the battery bank.

    Buck Converter


    Without the inverters, the CXX family is just a PWM (pulse width modulation) On/Off switch...

    Buck converters also use PWM internally to control their operation--Probably the root of the confusion...

    A MPPT type charge controller costs about 3-5x more than a PWM / On-Off controller. And typically MPPT are used with larger systems (say more than 400-600+ watts)

    PWM's tend to be used for smaller systems (~200 watts and under).

    The MPPT is a more flexible controller that can allow you to place the solar panels much farther away from controller/battery shed because you can use a higher voltage solar panel array...

    They are nice--but not cheap.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • garlicgarlic Posts: 43Solar Expert
    Re: Difference in "PWM" controllers

    Thank you folks for ironing out this wrinkle.

    I knew the difference between mppt and pwm.I thought maybe
    I had missed some disparity between the Cxx CC's and other pwm types and
    that motivated me to ask what they might be.

    Thank you again,

    Garlic
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