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Motor Control ICs Forum Discussions

Vel
Level 1
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First reply posted First question asked Welcome!

Hi,

I am designing a controller for PMSM where the torque increases gradually with speed.

I have developed a controller board based on REF-Fridge_D111T (https://www.infineon.com/cms/en/product/evaluation-boards/ref_fridge_d111t_mos/).

I am controlling the speed using Vsp analog input.

The maximum speed of motor in parameter file is 18000 RPM.

It's an IPM motor with field weakening current limit of 100%

The motor can run up to 18000 RPM at no load,in field weakening region without any issues.

But If I try to run the motor with load at 18000RPM,  at some point (14000RPM) the load torque is more than motor  torque, and controller goes out of control and the gate kill is triggered. The speed at which the gate kill is triggered depends on the value of load torque. 

The behavior I am expecting from the motor is , instead of triggering gate kill and stopping just keep running at lower speed (maximum achievable speed for the given load torque).

Just to give you more details on my application,

Different loads will be applied to the motor manually, so load torque is a variable.For different load torque the attainable maximum speed of the the motor will vary. 

If I set up maximum speed as 18000RPM, then loading the motor with higher loads will trigger gate kill at 14000RPM. Instead I want the motor to run at 14000RPM without stopping. 

 

Please give me some ideas on how to configure this?

Thanks:)

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1 Solution
Krupashankar
Moderator
Moderator
Moderator
250 replies posted 100 solutions authored 5 likes given

Hi @Vel,

Gatekill fault is triggered during over current condition. Motor current limit has to be modified based on the application need within safe operating current limit.

Please refer to section: 2.2.3.2 Over-current protection in REF_Fridge_D111T_MOS user guide

Please try modifying Question 58 - Current Regulator Bandwidth this helps in better current regulation for varying load.

Can you please share the motor datasheet and MCE Wizard Configuration file ( .mc2) this will help us to understand the issue better.

 

Thanks,

Krupashankar

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3 Replies
Krupashankar
Moderator
Moderator
Moderator
250 replies posted 100 solutions authored 5 likes given

Hi @Vel,

Gatekill fault is triggered during over current condition. Motor current limit has to be modified based on the application need within safe operating current limit.

Please refer to section: 2.2.3.2 Over-current protection in REF_Fridge_D111T_MOS user guide

Please try modifying Question 58 - Current Regulator Bandwidth this helps in better current regulation for varying load.

Can you please share the motor datasheet and MCE Wizard Configuration file ( .mc2) this will help us to understand the issue better.

 

Thanks,

Krupashankar

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Hi @Krupashankar ,

Thanks for your reply.

My rated current is 2.5A, RMS.

I have kept the over current trip level quite high as 9A.

Vel_0-1671141395439.png

 

At full load when the gate kill happens, I monitor the current in MCE designer  where the peak is not more than 2.5A. But still the gate kill triggers. I don't quite understand how this got triggered. 

I paused the trace at the instant when the gate kill happened, please find the image below,

Vel_1-1671144787771.png

I read the flux_m register value as 2048 counts (which i believe it means my motor parameters are correct)

Vel_2-1671145007824.png

what could be the reason for gate kill?

 

Thanks.

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Krupashankar
Moderator
Moderator
Moderator
250 replies posted 100 solutions authored 5 likes given

Hi @Vel,

Can you please capture the current trace at the point of gatekill fault?

This can be captured by following setting:

Right click on trace -> Define trace 

Krupashankar_0-1671435511919.png

Can you please share the motor datasheet and MCE Wizard Configuration file ( .mc2) this will help us to understand the issue better.

Thanks,

Krupashankar

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