• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 49 subscribers
  • Views 344 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

INA169: Non Linear output when I have higher loads.

INA169: I want to measure 3 phase motor phase with shunt and the ina169.

Okki
Prodigy 30 points
Part Number: INA169
Other Parts Discussed in Thread: INA240

A brushless DC electric motor (BLDC motor or BL motor), also known as electronically commutated motor (ECM or EC motor) and synchronous DC motors, are synchronous motors powered by direct current (DC) electricity via an inverter or switching power supply which produces electricity in the form of alternating current (AC) to drive each phase of the motor via a closed loop controller.

So I just want to measure the positive current of each phase for the BLDC motor[total 3 phases], so I tried to simulate it with the INA169 in software TINA.
I just cant get a good configuration , DC configuration works fine. BUT INVERTERING voltage makes it harder. The shunt resistor should measure till 7A.

I hope to hear from someone with instructions/solutions.

  • 0
    Prodigy 30 points

    This is the way i tried:

  • 0 in reply to Okki
    TI__Mastermind 26485 points

    Hello Okhan,

    The reason you are seeing the output drop to zero is because the VCM drops below the 2.7V at about 7.5ms.  The INA169 opeating VCM voltage is between 2.7V and 60V for its linear operating range.

    The absolute maximum is  -0.3V to 75V so going to -48V will not work with this device.

    I assume this is not the way it will be connected and the VCM will not go below GND. 

  • 0 in reply to Javier Contreras4
    Prodigy 30 points

    Hello Javier,

    Thankyou for your reply, as you can see I try to get the inline method done. Is there any other way to do this better then what I got?
    I was thinking that maybe I just use this method with the focus on only measuring the positive VCM between 0-48Vdc( or 2.7Vdc till 48Vdc)....

    Maybe an important thing to remember is that the motor will also generate back emf so the current on the BLDC motor phase for example phase A will flow to both directions. 

  • 0 in reply to Okki
    TI__Mastermind 26485 points

    Hello Okhan,

    You may want to consider using the INA240 as it is bidirectional.  Or you can attempt using another bidirectional device.