Current calibration

Altair Forum User

Submitted by Mala Gowda on Mon, 10/29/2012 - 10:57 

 

 

Hello:

I am able to generate a ramp from hall signals and run Open loop FOC but I notice amplitude of currents sensed are not equal in amplitude, there is some imbalance, could be because windings are not balanced. So how could we correct this and operate in closed loop. How can we calibrate the currents before driving into closed loop. In closed loop PWM’s issued by SVM block isn’t good, I could notice DC currents in all the three phases. Please suggest me on this.

Regards, MALA

Altair Forum User

Submitted by Anders89 on Mon, 10/29/2012 - 21:03.

You can put small fixed signals on each phase and measure your shunt voltages both in VisSim and externally to see what your variation is. At boot time you can calibrate to phase A and store the variation coefficients for phases B and C and apply them in the ADC read scaling. A compound block enabled with the $firstPass variable will execute at boot time before the first interrupt is taken.