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DRV10983

Peter Han1
Intellectual 1020 points
Other Parts Discussed in Thread: DRV10983

i need some help with motor driver.

1. Do you have any good idea to measure ambient temperature of a IC ? How to calculation the junction temperature when we know ambient temperature?

 

2. infrared thermometer can get junction temperature directly, is it accurate ? it there have any error value?

  

3. could we share close loop control algorithm to other?

 

4. what’s the function about T control advance value ? and what the best value ?  

 

Thank you for your kindly support.

  • 0
    TI__Guru** 114905 points
    Hi Peter,

    For questions 1 and 2, I suggest you look at ti.com/thermal. There you will find much information regarding thermals.

    For questions 3 and 4, our experts are being notified. They should respond soon.
  • 0 in reply to Rick Duncan
    TI__Expert 8885 points

    Hi Peter,

    For remaining questions 3 &4:

    3. could we share close loop control algorithm to other? -

    The closed sinusoidal sensor-less algorithm of DRV10983 is based on back-emf calculation as against back-emf measurement typical done in 120deg trapezoidal control. The actual implementation is propriety and can not be disclosed.

    4. what’s the function about T control advance value ? and what the best value ?  

    Below is explanation about T-advance angle feature of DRV10983/75:

    To get maximum efficiency for PMSM motors, the motor current in stator winding should be in phase with back-emf because the air-gap power delivered from stator to rotor is = 3*E*I*cosø.

    Here E- is back-emf voltage phase to center tap

              I – input motor winding current   

             Ø- phase angle between back-emf & current

    Now to achieve cosø=1 to get maximum power delivered, Ø should be zero means, current & back-emf should be in phase.

    Refer to attach picture for Motor model and corresponding phasor diagram:

    To achieve the objective to inject current in phase with back-emf, Vinv should have phase advance from back-emf- E. The advance angle is decided by motor resistive & inductive drops.  

    Now there are two ways, Ɵadv is achieved in DRV10983:

    1. Fix time: In this method, Ɵadv is fixed. It is achieved by calculation the zero-crossing of back-emf and advancing the angle of applied voltage with respect to it as decided by the Tadvance setting.  Max range of phase-shift is ~4msec, one need to zoom the scope capture near current zero-crossings with respect to applied voltage to get good reading of the phase-shift.
    2. Variable time: means the angle (time) is not fixed, but calculated based the motor speed and current. It this condition, the Tsetting is not the advance angle (time), but  stator impedance angle or the LR time constant. This equation is the how to calculate tadv or Ɵadv  from stator angle.

    tadv = tSETTING × (U-BEMF)/U.

      We suggest customer to choose ‘fixed Tadvance angle’, in which case this equation is not used.

    DRV10983_Tadvance_angle.pdf

    Best Regards

    Milan-Motor Application Team