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DRV421: DRV421 for 400A DC current

Mohamed Omar
Prodigy 20 points
Part Number: DRV421

Dears,

I have an application and I need to use DRV421 to measure DC current, the max DC current to be measured is 400A.

Can the DRV421 measure 400A? 

If it can measure 400A what is the number of windings of the compensation coil? Also, How can I design the core? and finally, where can I find this coil?

Thanks in advance

  • 0
    TI__Mastermind 28640 points

    Hello Mohamed,

    You can design a DRV421 to measure 400A DC.  I would use this calculator to determine the number of turns required and the Rshunt you would need.  Keep in mind the inductance matters (see here) and that will be dependent on the air gap and the number of windings.

    For 400A there will be a couple of tradeoffs.  You may need to increase the diameter of the windings as the resistance may get to large to have the DRV421 H-Bride to drive it along with the Rshunt resistor.  If you have a higher voltage supply available you could  increase the drive capability with an external circuit like this TIPD184. 

    Use this calculator to get the information about designing with the DRV421.  You will need to get the compensation coil inductance and resistance as input parameters.  If it cannot drive the coil the calculator should tell you but make sure you place the resistance of the winding based on the highest temperature of the design due to large Temperature Coefficient of copper.

    Download the “DRV421 – System Parameter Calculator” (http://www.ti.com/product/DRV421/toolssoftware)

    Use FEMM to calculate the inductance of you core design.  We have some scripts available here in the E2E post that can help you get the information from the mechanical design of a core.

    The core/coil can be difficult to get.  One can easily purchase a core and cut the air-gap and do the winding yourself for prototyping but getting a vendor to custom make magnetics is usually a higher cost unless your volume is high.  There are vendors you can reach out but there is nothing off the self I have found to be able to use this.  

    Some magnetic core vendors in no order: Vacuumschmelze, Sumida, Pulse, Wurth, GCI.  

    Any custom magnetic core vendor should be able to make what you need but the cost and volume will be the challenge.

     

  • 0 in reply to Javier Contreras4
    Prodigy 20 points

    Great thanks for your kind and fast reply,

    Can you provide a solution (current sensing development board) for our application 400 A including the DRV421, Compensation Coil, and the Shunt resistor?

    Best Regards,

  • 0 in reply to Mohamed Omar
    TI__Mastermind 28640 points

    Hello Mohamed,

    All we have is the DRV421EVM that you can order.   This does not include the compensation coil but it does have a Shunt resistor that may need to be adjusted for you current levels.