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Current sensor

TruBlu
Prodigy 115 points

Other Parts Discussed in Thread: TMDSHVMTRINSPIN, CONTROLSUITE, MOTORWARE, DRV8301

Hallo,
 
InstaSpin needs 2-3 shunt for the current mesurment!
 
Is it also possible to use 3 LEM to mesure direct the 3 motor phases?
(I case of a IBGT-Module with common emitter)
 
Can i configurate InstaSpin in this case?
(I havn't found a parameter!) 
  • 0
    TI__Guru** 119680 points

    Daniel,

    Yes, you can use phase current measurements. Phase currents reduce the dependence on a sampling window which makes things even easier.

    I assume you are only using 2, so all you do is in your user.h select CURRENT SENSORS (2) and make sure you run the currents to the same ADC channels on your HW design.

    Nothing else needs to change, the PWM will still kick off the ADC at timer = 0 and take the current & voltage measurements.

     

  • 0 in reply to ChrisClearman
    Prodigy 115 points
    Chris,
     
    I have see that in the TMDSHVMTRINSPIN also the Sum of the Current goes to the DSPs ADC.
    What does InstaSpin do with it?
     
    Can a short circuit to earth be detected with both current measure method?
  • 0 in reply to TruBlu
    TI__Guru** 119680 points

    Daniel,

    For InstaSPIN we are not using the sum current in the control algorithm or for protection.  The ADC doesn't even sample this signal in the MotorWare projects.  You can, we just don't.  This signal is used on the hardware for other controlSUITE based projects.

    For the MotorWare projects we use the Trip Zone (TZ) feature of the Piccolo devices, but the source of this trip is coming from a comparator on the board that monitors and ORs each phase.  See U2 and U3 on the schematic.

    The DRV kits have the Piccolo TZ fed by the DRV Fault signal. In the case of DRV8301 the fault is being decided off the FET gate voltage, it doesn't even look at shunt currents (since they are external to the DRV8301).

    For your own hardware you could use a the comparators on the Piccolo chip for phases, or you could use the bus current. The phases are more robust protection though.