IGBT driving with PIC

Discussion in 'Embedded Systems and Microcontrollers' started by jean120, Jun 18, 2016.

  1. jean120

    Thread Starter Member

    Jan 24, 2016
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    Hello,could you please advise me on how I can fully drive an IGBT for a three phase bridge circuit?
    I am making a three phase induction motor control circuit and this has to provide the required voltage to the terminals of an induction motor three phase.
    I am applying 45V DC at the three phase bridge and the voltage at the terminal is 11VAC,could you please let me know how I can advance and provide more output than what I have now ,you understand very well that if I input 440VDC the output should be around 100VAC which is not enough and also the IR21362 which I am suing as IGBT driver is becoming very hot,what can I do,
    The IGBT I am using is IRG4PC50FD
    at 5KHZ and the quartz is of 20MHZ the bootstrap capacitors are of 22uF/50V.

    Please advise.
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Without a schematic it's difficult for us to offer advice.
     
  3. jean120

    Thread Starter Member

    Jan 24, 2016
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    It is not possible for me to provide the circuit because the proteus I am using doesn`t have the IR21362 as a package so I can`t draw the schematics.

    Please help.
     
  4. JohnInTX

    Moderator

    Jun 26, 2012
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    Have you looked into the wealth of information available from Microchip - application notes, technical briefs, datasheets etc?
    http://www.microchip.com/design-centers/motor-control-and-drive

    That is kind of immaterial to the actual need for a schematic. How about a pencil and paper sketch? Take a clear picture of it and post it using 'upload a file'.
     
    Last edited: Jun 18, 2016
  5. ian field

    Distinguished Member

    Oct 27, 2012
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    An IGBT is basically a hybrid Sziklai pair - a regular MOSFET with a PNP emitter follower hanging from the drain - generally speaking, driving with a MCU requires a logic level part just the same as if it was just a MOSFET. Standard MOSFET drive chips should usually mean you can use regular MOSFETS (and IGBTs).

    IGBTs were developed as a solution to the high RDSon with the MOSFETs of the day, but the PNP emitter follower output makes them slow. There are modern MOSFETs with RDSon low enough to compete with IGBTs.
     
  6. Papabravo

    Expert

    Feb 24, 2006
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    I see a part with a threshold voltage of 3-6 Volts, so controlling it directly with the processor is out of the question. It will take more voltage to turn the device on completely. It also has an asymmetrical turn on/turn off characteristic, which means you need to pay attention to the transition times to avoid excessive power dissipation while the gate is being discharged. the usual way to do this is with a current source/sink. A logic level input driver chip is recommended.
     
  7. jean120

    Thread Starter Member

    Jan 24, 2016
    75
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    Hello,here is the circuit for three phase induction motor control using IR21362 and PIC18F46K22,with this implementation the IGBT driver is becoming very hot at 5KHZ but the motor shaft tends to move only the voltage is very low around 11VAC on the motor terminals,at 20KHZ as switching frequency the Driver is not reacting at all,the IRG4PC50FD operate at 1 to 5KHZ.
    Please find in attachment the schematic I used.
     
  8. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Why are you using such a high switching frequency?
    Your connections for the ITRIP and VSS pins of the driver IC bear little resemblance to the 'typical connection' shown in the IC datasheet. Where is your current sense resistor?
    Shouldn't VSS be at or very near ground potential?
     
    Last edited: Jun 19, 2016
  9. jean120

    Thread Starter Member

    Jan 24, 2016
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    Hello Alec_t,could you suggest me the frequency I may use for controlling those IGBTs?
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
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    You probably want to stay under about 15kHz - the output section of an IGBT is a PNP emitter follower, which is about as slow as it gets.
     
  11. jean120

    Thread Starter Member

    Jan 24, 2016
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    Which frequency may I use for handling this problem?

    Please help!!
     
  12. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    As you said above :-
     
  13. jean120

    Thread Starter Member

    Jan 24, 2016
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    Hello Alec_t,could you advise on what should be done for solving the problem?Please help!!
     
  14. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    1) Make sure you have the IR21362 wired correctly (see the datasheet). See post #8.
    2) Try a driving frequency of ~1kHz or less. But to get a 3-phase motor started won't you have to ramp up the frequency from a much lower value?
    3) Read this and follow the advice.
     
  15. Robin66

    Member

    Jan 5, 2016
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    There's a lot of "Please help" on this thread. Is this a hostage situation?
     
  16. ian field

    Distinguished Member

    Oct 27, 2012
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    When I did servicing, I've seen SMPSU IGBTs driven at about 50kHz - but at that frequency, they lost most of their advantages over MOSFETs. Failure due to switching losses and excessive dissipation weren't exactly rare.

    15 - 20kHz is a reasonable frequency for IGBTs - but PWM motor drive probably doesn't need more than a few hundred Hz.
     
  17. jean120

    Thread Starter Member

    Jan 24, 2016
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    how to obtain those frequency?
     
  18. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Use the micro to generate the required frequency.
     
  19. jean120

    Thread Starter Member

    Jan 24, 2016
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    I was meaning using the codes I already have how the 15KHZ can be obtained.I am referring to microchip AN843.
     
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