how to get bus current with ti demo board(using pmsm motor)?

even mi

i have found a related answers in e2e forum,it only work at motor rotated up.I want get bus current almost whole period.

is there any solution which get bus current from 3_phase current or any other solution can be realized on TI demo board(069 lauch pad)?

over 8 years ago

0 Yanming Luo over 8 years ago

TI__Guru** 115400 points

It's difficult to get a very accurate current from motor 3 phase current if without any other current sense. You can calculate the motor output power, and need to know motor efficiency, inverter efficiency, dc bus input voltage, and then calculate the dc bus current.

0 even mi over 8 years ago in reply to Yanming Luo

Prodigy 105 points

hello Yanming,
I have seen a related answer by your collegue Dave（wisconsin）,
In this thread: e2e.ti.com/.../470634
Because the thread is long-time ago,I can't get futher reply from Dave.
Do you known his meaning about add 3_shunt_voltage together to get current bus?
How to correctly add 3_shunt_voltage using analog circuit ?
thank you

0 Yanming Luo over 8 years ago in reply to even mi

TI__Guru** 115400 points

It's still motor current like using single current shunt. What do you want to use for bus current?

0 even mi over 8 years ago in reply to Yanming Luo

Prodigy 105 points

I just wanna to add current protection or current limitation

0 Yanming Luo over 8 years ago in reply to even mi

TI__Guru** 115400 points

It can be used for current protection if you add an external comparator or connect it to the ADC pin of C2000 if the ADC pin support internal comparator.
And you need to sample the current like single current shunt to get the real motor current. Actually, the current is equal to one of motor phase current every sample time. Please refer to section 17 of InstaSPIN user guide (SPRUHJ1G).

C2000™︎ microcontrollers

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how to get bus current with ti demo board(using pmsm motor)?