Manual Parameter calculation for Motor Tuning in FreeMASTER

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Manual Parameter calculation for Motor Tuning in FreeMASTER

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NXP Employee
NXP Employee
 

Hi,

I need some clarification on the document below for calculating parameter manually.  

I am following the AN4680 document, which describes the following for calculating Back-EMF. It is stated, "For three-phase measurement if the neutral point is not accessible, it’s possible to create the artificial neutral point from all three voltage probe clips connected together". I did the connection as given below(Fig.1 assuming the Motor has star topology). 

 

Fig.1.png

Fig. 1 

 

Note: I am working on motor control for Igus MOT-EC-60-CIA (3 phase EC/BLDC Motor,NEMA24) motor using RT1050-EVK-B and FRDM-MC-LVPMSM.  

  1. Motor Parameter 

1.1)How to check if the Motor have Star or Delta Topology? 

1.2) Does the measured Vpk-pk correspond to phase-neutral or phase-phase voltage?(Unknown: Motor have Star or Delta Topology) 

1.3) If it is Phase-Phase Voltage, can it be converted to Phase-neutral voltage by using the following formula,  

                    Van= {Vab/sqrt(3)}   ------------------------------------------- [1] 

where, 

Van= Phase{A}- Neutral Voltage 

Vab= Phase{A}- Phase{B} Voltage 

  1. Application Control 

2.1) What is the reason for the error- "FAULT: Under Voltage" and "FAULT: Over Current" in the FreeMASTER? 

[1] Reference: https://myelectrical.com/notes/entryid/8/three-phase-power-simple-calculations 

Not sure if its related: The led on the power supply adapter is blinking when the i.MX board is connected to the Laptop and simultaneously the Laptop is connected to docking station. If the Laptop is not duplicated via docking station, the green led on the adapter is constant. 

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NXP Employee
NXP Employee

Hi,

Here are some answers:

1.1) Try the following test:

joseftkadlec_0-1603778094954.png

1.2) At the star topology it corresponds to phase-to-neutral voltage.

2.1)

Undervoltage fault: is triggered when the DCbus volateg drops under a certain level. On FRDM-MC-LVPMSM use 24VDC.

Overcurrent fault: is triggered when DCbus current goes over a certain level. This fault is done using MCU peripheral interconnection: DCbus current analog value is brought to comparator(CMP), CMP output is brought to PWM fault input which can (in case of fault) immediately turn off PWM outputs. Overcurrent fault threshold is fixed and can be changed in code only.

NOTE: Faults in FreeMASTER marked as Captured don't clear automatically and are ON even after the fault condition doesn't apply anymore (it's like a fault history). Must be cleared manually.

BR,

Josef

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NXP TechSupport
NXP TechSupport

Hello @nxf63743,

Answering some questions:

1.1)How to check if the Motor have Star or Delta Topology? 

Most of the BLDC motors used the star configuration but if you want to check the confirm this I will suggest looking at the motor documentation.

2.1) What is the reason for the error- "FAULT: Under Voltage" and "FAULT: Over Current" in the FreeMASTER? 

In the code, there's a structure called g_sM1Drive.sFaultThresholds that has limiting values for the operating so if any of these faults is triggered, this could be caused by a problem with the connection, a synchronization fault, or an incorrect tunning of the motor. Please check the following application note that explains the use of the MCAT tool (link).

About your other questions, I'm still looking.

Best Regards,

Alexis Andalon

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NXP Employee
NXP Employee

Dear user,

I'm afraid I we cannot support this kind of questions in FreeMASTER forum where you have originally posted it. FreeMASTER is a general tool for data visualization and embedded application control. It is true that many Motor Control reference designs and application notes use FreeMASTER to demonstrate various algorithm features and to enable to tune the application performance. However, the FreeMASTER team does not have any insight to these applications.

I have just moved your question here to the Motor Control and Smart Energy product forum. 

Thanks,
Michal

 

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