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HVP-MC3PH 16A Current Mods:  Software Triggering Non-Clearable Faults

Question asked by Frank Roberts on Dec 26, 2017
Latest reply on Jan 11, 2018 by Adam Reynolds

Hello I have the HVPMC3PH.  I have made modifications to the HVPMC3PH along the lines of the 'Protection and Hardware Changesv4.pdf and AN5254, Adapting KMS for Custom Hardware.  All of the changes I have made are relatively straightforward and comparable changes to what is described in the 2 PDF's mentioned earlier that describe modifications to allow for higher current drive. 

  After making these changes I now have 2 "Non-clearable" faults that are listed below...

   1) Current Sensor Calibration Fault

   2)  ADC Offset Fault

 

KMS GUI also reports that the DC Bus voltage is 0V when I can clearly measure 1.2V at TP31(ADC input after Resistor Divider) and measure 160V @TP1(DCB_Pos).

 

In probing the PCB with a DMM it appears that something is being detected in software that is not allowing the PFC portion of the circuit to come 'alive' as there are no PWM signals driving the PWM_PFC1/PWM_PFC2 pins which control the Gates on the N-FETs Q1 & Q2 on page 3 of the HVPMC3PH schematic where all the PFC circuitry lies.  Being that Q2 and Q1 never turn on there is no signal feeding into the OpAmps U2A/U2B thus completing the loop of the fault. 

 

From what I can tell the faults shown above are something taht are being triggered by software not adjusting to the updated parameters put into the KMS.  I am following the exact procedure described in 'Protection and Hardware Changesv4.pdf'

and I can clearly see the header file gets updated and then the newly compiled program gets loaded onto the MKV31F after selecting "Run Project on MCU". 

 

Can someone that is familiar with the KMS GUI/Software and/or HVPMC3PH provide some insight here?  We simply can't make use of this design unless it can drive higher currents above 8A and the Fairchild 3PH Inverter can clearly handle currents well above 8A.  I realize 16A is pressing a bit but we will only see current spikes above 12-14A for very short durations upon startup.  Ultimately we will develop our own PCB of course suited for higher currents but we need to validate this design can drive our motor with at least a minimal load and right now 8A is not enough.

 

Any input/guidance would be greatly appreciated!!  I have attached the documents referred to in this and also a document that describes precisely the components we have changed to adapt the HVPMC3PH to allow 16A.

 

Regards,

Frank

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