How to measure the Phase Voltage?

[jiangfeng]

Dear Daniel:

Which pin is used to detect the Phase Voltage  in the following figure? HS0,HS1,and HS2?

Besides， Is the phase voltage described above correspond to Ua,Ub and Uc in the flowing figure?  Thank you very much ,my friend.

[Daniel_Popa · Accepted solution]

Hi jiangfeng‌,

I presume you need it for the BLDC sersorless drive based on phase BackEMF zero crossing. At each commutation phase (is you use the standard 2 out 3 phase commutation technique that maximize the torque) you will need to read the HSxxx that corresponds to the un-powered phase. You will need to implement your own logic algorithm to read and update the phase voltage of each phase.

In case of PMSM it is not very helpful since since by default you know/control the amount of voltage that you apply to the motor. Overall in this case might be helpful to know if a transistor is broken.

And, yes - it corresponds to Ua/Ub/Uc phase voltages.

Hope this helps!

Daniel