Hi everyone,
I am having some trouble to measure the total current used by our motor by using sensorless FOC technique. I am using the DRV8301 integrated op. amps. with two low sides shunt resistors. I have dimensioned the shunt resistors (20 mohms) so I can have up to +/-6A (scaled to 0-3.0V ADC, offset on 1.65V) with 10x gain on the op. amps.
I have no trouble with the control of the motor and I read nice sine waves from the currents feedback. Now, when I try to compute the total current used by the motor, I get values off the weed and very noisy and cannot match what I am measuring with current delivered by my laboratory power supply.
I basically take the current values from (Park.Isq and Park.Isd) and compute the norm from it : Itotal = sqrt(Park.Isq*Park.Isq + Park.Isd*Park.Isd) * baseCurrent.
ADC value varies between 1.0 which corresponds to +6A and 0.0 which corresponds to -6A.
Am I missing something?
