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DRV8307: Hall sensor spacing

Phil Young
Prodigy 40 points
Part Number: DRV8307

Is the DRV8307 compatible with 120 degree spaced hall sensors and if not, is there a way to make it compatible? 


Thanks,


Phil

  • 0
    TI__Guru** 114905 points
    Hi Phil,

    Yes the device is compatible with 120 degree spaced hall sensors.
  • 0 in reply to Rick Duncan
    Prodigy 40 points
    Hi Rick,

    Thanks for the reply. I've tested two types of motors on the DRV8307EVAL boards; one has 120 deg spaced halls and the other has 60 deg spaced halls. The 120 deg motor doesn't work at all, but the 60 deg motor works beautifully. Both motors use the same hall sensor IC, at least according to the mfg, both are 24V but they don't have the same number of poles; one is a 4-pole, 60deg spacing, and the other is a 14-pole, 120deg spacing and it's the one that doesn't work correctly with the DRV8307. Thoughts?

    Thanks,

    Phil
  • 0
    Prodigy 40 points
    Hi Rick,

    Thanks for the reply. I have tested two motors on the DRV8307EVM; one is a 4-pole rotor/6-pole stator with halls spaced at 60deg and the other is a 14-pole rotor/12-pole stator with halls spaced at 120 deg. It's the 14-pole motor that doesn't work with the DRV8307, the 4-pole motor works beautifully. I've tried all winding/hall combinations on the 14-pole and it just won't work properly. I verified the bad operation with two other samples of the same motor and got the same results. Thoughts? Suggestions?

    Thanks,

    Phil
  • 0 in reply to Phil Young
    TI__Guru** 114905 points
    Hi Phil,

    Please refer to this post: e2e.ti.com/.../1429865

    For the 4 pole motor, spacing of 120 deg is correct.
    For the 14 pole, the spacing is 17.14 deg. Setting Hall1 @ 0, Hall2 @ 17.14 + (6 * 17.14) = 120, and Hall3 @ 34.28 + (12 * 17.14) = 240 deg results in the same spacing.

    Are you sure you have the phases connected correctly for the hall sequence of the motor?
  • 0 in reply to Rick Duncan
    Prodigy 40 points

    Thanks for the spacing info. 

    I'm absolutely sure I have the phases and halls connected correctly.  Just for kicks, I went through all the combinations just in case; none of them worked on the DRV8307. 

    By my calcs my 4-pole motor should have halls spaced at 60deg, which makes sense.  I tore apart a 14-pole motor and the sensors are physically spaced at 120deg, without a doubt.  Also, I'm running a 14-pole motor right now with a different driver, the L6235Q from ST Micro, and it's working beautifully.  The commutation waveforms look perfect.     


    Phil