KV31F adc offset and current sensor calibration fault

[jeremyprater]

Hello,

I just unboxed my new FRDM-KV31F and FRDM-MC-LVBLDC motor kit.

I preformed the following actions:

   - Installed the FRDM-MC-LVBLDC on top of the FRDM-KV31F board

   - Connected a small drone motor to the motor connection header

   - Connected a 12V bench power supply to the FRDM-MC-LVBLDC

   - The red/blue led started blinking (as expected)

   - Connected the USB cable. A USB drive was detected in by windows with some HTML files and a driver in it.

   - Started Kinetis Motor Suite

   - Connected to the target

   - Two faults are preventing me from proceeding past step 2:

Current Sensor Calibration Fault

ADC Offset Fault

If I remove the FRDM-MC-LVBLDC shield and restart the KV31F, it still shows the fault with the shield removed.

I tried another power supply to verify that I had a stable 12 VDC source to the FRDM-MC-LVBLDC

It was measured at 12.2 V.

Both parts were purchased from digi-key. Perhaps I received some bad hardware? I paid over $70 with two day shipping to get started on this project and I can't get the motor to spin!

I searched google and the NXP community forums and found no one else with these problems. The Kinetis SDK provides some documentation for the faults.

6.2.5 struct DSM_nonClrFaults_t::DSM_nonClrFaultsBits_s

Drive state-machine non-clearable faults bits structure.

Data Fields

bitfield_t __pad0__: 5 unused bitfields

bitfield_t adcFault: 1 B0.3 DSM ADC offset fault on phase A, B or C bitfield

bitfield_t calibration←- Fault: 1 B0.2 DSM current sensors calibration fault bitfield

I checked the voltage on each motor connection to ground, and they are as follows:

Phase A - Ground : 0.640 Vdc

Phase B - Ground : 0.640 Vdc

Phase C - Ground : 0.640 Vdc

Phase A - Phase B : 0.00 Vdc

Phase B - Phase C : 0.00 Vdc

Phase C - Phase A : 0.00 Vdc

Any suggestions?

Thanks,

Jeremy

[eduardo_viramon · Accepted solution]

Jeremy,

You're using the wrong board. The KMS kit will work with FRDM-MC-LVPMSM, not LVBLDC.

The LVPMSM board is essential for KMS because it is the board that has the current-sensing shunts and op-amps necessary for field-oriented control. The LVBLDC board, on the other hand, is designed for trapezoidal control and does not have the needed circuitry.

I'm sorry about this confusion.  My recommendation: return the LVBLDC and exchange an LVPMSM.

Eduardo Viramontes

[jeremyprater]

Eduardo,

Thanks for the info!

Will the FRDM-MC-LVPMSM work with with a sensorless velocity setup with a 3 phase BLDC motor?

Thanks,

Jeremy

[linestream-adam]

Jeremy,

Yes the FRDM-MC-LVPMSM board will be able to control the sensorless velocity of a BLDC motor.  BLDC motors can be considered a subset of PMSM motors.  The KMS application will use sensorless FOC instead of sensorless six-step.

[jeremyprater]

I also sometimes receive a DC Bus under-voltage.