Replacing Resistive Shunt current sense with Hall-Effect sensors

[gerald23]

Posted on March 09, 2018 at 16:27

Has anyone replaced the shunt resistors with a isolated hall-effect current sensor?

We need isolation for safety, but there is concern of introducing phase lag in the current signals.

#iso-shunt-current #isolated-current #hall-effect-current

[Andrew Neil]

Posted on March 09, 2018 at 16:43

the (sic) shunt resistors

What shunt resistors?

Remember that we have no idea what your application is, or what components it is currently using!

there is concern of introducing phase lag in the current signals

Surely, the datasheets of the sensors in question will quantify that?

If not, use the sensor manufacturer's support channels...

[gerald23]

Posted on March 09, 2018 at 18:57

My bad. The application is a brushless DC permanent magnet motor controller based on the STSPIN32, but at higher voltages.

The intended application of the STSPIN32F0 is to use resistive current shunts in the low legs of the H-bridge drivers. (

http://www.st.com/en/motor-drivers/stspin32f0.html

 )

For UL Compliance, going above 50V requires some form of isolation between the high voltage section and end user.

With the isolation requirement we are looking at cost effective isolation methods and hall-effect current sensors is about the cheapest. Unfortunately I have NOT found any documentation addressing this approach.

So can anyone shed some light on this subject?

[henry.dick]

Posted on March 09, 2018 at 20:57

you may want to do some experiment to see if phase lags are a problem for your application.

without that, there are other ways, for example isolator chips, or linear optical couplers, or digitization locally, ....

but having some experiment of your own is better than listening to someone over the net.