Recommended MOSFET Gate Driver and MOSFETs for H-Bridge Motor Controller

Discussion in 'General Electronics Chat' started by jegues, Aug 5, 2013.

  1. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
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    Evening gents,

    I'm trying to pick out MOSFETs along with a MOSFET Gate Driver from International Rectifier that will suit my needs. (See http://www.irf.com/indexsw.html)

    The MOSFETS will be used in an H-Bridge configuration, with the MOSFET Gate Driver driving the gates of each respective MOSFET.

    This circuit will be used for a motor controller.

    The batteries used to power the motor are Lithium Polymer batteries manufactured by GBS batteries. The batteries have sixteen 3.6V cells connected in series to have a rated voltage of 55V and a capacity of 60Ah.

    The motor is a permanent magnet brushed DC motor from Motenergy, model part number ME0708. The motor has a lead to lead resistance of 0.01Ω, and a lead to lead inductance of 0.055mH at 120Hz. The motor is rated for 48V and 100A, but can handle up to 300A for one minute, and has maximum peak torque of 37.8 Nm and maximum rotor speed of 5000rpm.

    A switching frequency of ~15kHz is assumed.

    The datasheets for both the motor and LiPo battery bank are attached below.

    1) What part number MOSFETS would do you recommend I use? Also, for my current requirements (i.e. up to 300A for one minute) should I use multiple MOSFETs in parallel, or opt out for a single MOSFET with higher current carrying capabilities?

    2) What part number MOSFET Gate Driver would you recommend I use? Assume the MOSFET Gate Driver will be driven from a 12V supply.

    Thanks again for all your help and any suggestions/advice/recommendations you may have for me!

    EDIT: What I've found so far,

    1) Placing two of these MOSFETs in parallel, http://www.irf.com/product-info/datasheets/data/irfp4468pbf.pdf
     
    Last edited: Aug 5, 2013
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    spark8217 likes this.
  3. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
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    Thanks for the excellent link! That clears things up tremendously.

    Has anyone ever heard of brick MOSFETS and brick IGBTs? Someone has suggested them for my application and I am trying to find out more information.

    Can anyone chime in on why I would want to choose an IGBT or a MOSFET for switching?

    I understand that IGBTs combine the best features of the MOSFET (i.e. ease of gate turn on and turn off from low-power logic circuits) and the BJT (relatively low power dissipation in the main collector-emitter circuit), but are there any practical reasons as to why using IGBTs over MOSFETs may be troublesome or more difficult to implement?
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    While I'm not any kind of expert, if you use a mosfet/IGBT driver(which you should) there should be little difference. A driver is so much easier than trying to do a H-bridge with discrete components. The drivers are made specifically to do the job. And they are a single IC saving board space.

    Never heard of a "brick" mosfet/IGBT. Are you sure they weren't talking about a IGBT module? This is a component with both a high side and low side device in one unit. They also have a bigger 'foot print' to transfer the heat to the heat sink better.
    http://www.powerguru.org/criteria-for-a-successful-selection-of-igbt-and-mosfet-modules/

    This link takes a while to download but has a good explanation on why and how modules are a good idea. http://www.google.com/url?sa=t&rct=...ApPxTQACUIeDaRqe1TSsSqA&bvm=bv.50310824,d.aWc

    The link I first gave you has a lot of other good, practical information in it if you click on the links at the bottom of the pages. And he makes it easy to understand.
     
  5. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
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    We will be using a MOSFET/IGBT Gate Driver module, but the H-Bridge itself will still be composed of discrete components, whether it be single MOSFETs wired in parallel or an IGBT module etc...

    Thank you very much for the links again, they are very helpful!
     
  6. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
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    On another forum, a reversible contactor approach was suggested to me, and I have modified my motor controller schematic slightly. (See attached)

    Does anyone see any practical/design problems with this?
     
  7. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Seen your posts on DIYEC. Again let me state I'm no expert. That said, the contactor S1 is is making your mosfets in effective. The contactor is switching to ground giving a short circuit in the supply voltage. It needs to go to the mosfets instead, they are what is going to give your ground/PWM connection.

    A DPDT switch or contactor needs to have a "crossing" or "X" effect in it, when shown in a schematic. And it also uses six(6) terminals not 4. See this link for what I'm saying; http://www.robotroom.com/DPDT-Bidirectional-Motor-Switch.html

    Also I have a good source for cheap IGBT modules if your interested and live in the US. You really should add you location to your member profile. Just the country is good.
     
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