Difference between single-shunt and three-shunt

Posted on May 17, 2011 at 10:15

Hi, can you explain what are the advantages and disatvantages of the single-shunt and the three-shunt method for current reading? Thank you!

I've to control a BLDC-Motor with Encoder. What is the best method? Single-Shunt or Three-Shunt???

Thanks!

Posted on May 17, 2011 at 10:15

if you drive motor at low rpm's with a high frequency of load changes , particularly in case you need position control ability first, three-shunt method will be more efficient with respect to controlability.there are some papers about this issue on ieee.it is easy to understand that in case using three shunt resistor, feedback information of motor is multiplied bye 3 in a single revolution. More information gives more good position controlability even at low rpms.

[ This message was edited by: muratterzi on 05-01-2009 12:36 ]

[ This message was edited by: muratterzi on 05-01-2009 12:50 ]

Posted on May 17, 2011 at 10:15

Hi Walterma

the single shunt advantage is the less hardware cost of the solution because it is required only one shunt and one OP amp

the three shunt solution require three shunt and three OP amps.

The reducion of the hardware cost is paid in term of a more complicated algorithm (increase in code size and workload) in term of current distortion (it is required a distortion to allows the current reading) and in term of power dissipation (using the st method)

Best regards

Gigi