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Inverter Gate Drive

Naveen Rangu
Intellectual 600 points

Hi,

I want to generate the PWM signal to drive Bridge Type MOSFET configuration.Is it okay to genearte two pair of PWM signals and directly fed to MOSFETs?

i want to generate 50Hz i.e 20mSec.pulse.  i tried to generate 50Hz   using HSPCLKDIV and CLKDIV prescalers in ePWM module but not getting low frequency output.

how to do that?

please help

 Note: i am using F28335 DSC

Thanks & Regards,

Naveen Rangu

  • 0
    Genius 4925 points

    Naveen,

    It is normally not OK to drive MOSFETS directly from Controller output. The Controller output pins do not have enough current drive capability to charge MOSFETs enough. 2nd part of your question - if you want to achieve 50Hz sinusoidal output with your inverter you don't want to switch your MOSFET's with the same 50Hz but much faster.

    Again: Study the theory of before posting here - we're not here to do your whole work...

    Best regards

  • 0
    Prodigy 40 points

    I agree with the reply post, and would like to add some more information that can guide you to the right answer.

    To increase the current sourcing and sinking capability of each MCU PWM pin, a "Gate Driver" IC is normally used.  Since the gate of a MOSFET is capacitive, it requires large positive and negative currents to charge quickly to turn the device off and on.

    The "theory" to be studied is the field of Power Electronics.  You can pick up any power electronics textbook to introduce yourself to some of these concepts.  This website has a collection and short review of some of the more common books.  http://www.smpstech.com/books/best-power-supply-books.html

    Hope this helps,

    Adam