Calculating Phase Currents in MCSPTE1AK144 Motor Development kit

[asrikrishnagovind]

For the NXP MCSPTE1AK144 Motor Development kit: 

In the DEVKIT-MOTORGD for BLDC/PMSM, the phase currents are being measured by using a shunt resistor in the low-side MOSFETS as per the schematics of the same.

However, as mentioned in the AN12235 document (AN12235: 3-Phase Sensorless PMSM Motor Control Kit with S32K144 – Application Note (nxp.com), page 7, the paragraph under fig. 5), this isn't the actual Phase current, and appropriate sampling must be done, (for example, using special circuits like Sample and Hold Circuit)

My query is, does the S32K144EVB take care of this necessary sampling and corresponding algorithm deployment using MATLAB? Thanks 

[adriantudor · Accepted solution]

Hello @asrikrishnagovind ,

The S32K144EVB board can sample and hold the phases currents at the right moment if the ADC, PDB, and PWM peripheral modules are configured in a corresponding way. In the most simple way, the flow of the ADC sample and hold process is like this: the PWM triggers the PDB which add or not some delay time, then PDB triggers the ADC sample. In this way, the ADC samples are not taken at an arbitrary moment, but at a precise moment. Then the rest of the job is done by the math algorithm.

Best regards,

Adrian

[mariuslucianand]

@adriantudor , 

Can you please comment on this one?

Thank you,

Marius