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

Okki

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.

over 4 years ago

0 Okki over 4 years ago

Prodigy 30 points

This is the way i tried:

0 Javier Contreras4 over 4 years ago in reply to Okki

TI__Mastermind 30750 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 Okki over 4 years ago 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 Javier Contreras4 over 4 years ago in reply to Okki

TI__Mastermind 30750 points

Hello Okhan,

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

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