Vac frequency fault

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AG_Serad
Level 4
Level 4
First solution authored 25 replies posted 25 sign-ins

Hello

Wa are using an IMC102T.

The PFC is activated and into MCEWizard v2.3.0.1, the parameter PFC 113 - AC Input Frequency is configured to 50-60Hz.

But on our customer, some time, we get error PFC PFC_SwFault = 0x08  = VAC Frequency fault.

 

I seen into MCEWizard v2.3.0.1, the parameter 132- Enable AC Input Frequency Protection. We can disable it.

Effectively, after change this value, the generated txt parameter file change the value of the parameter "PFC_FaultEnable"

change from 59 to 27 (Bit 3 pass from 1 to 0)

But, in the UserManual v1.34, on the chapter §3.3.5.9 PFC_FaultFlags, we can read:

"Gate kill fault and Vac Frequency fault cannot be masked by PFC_FaultEnable"

 

And on §3.3.5.6 PFC_FaultEnable, effectively, the bit 3 is indicated:

"[3] Reserved, must be set to “0”"

 

I have not the means to reproduce here a probleme on Vac frequency. But it is not serious to say to my customer I disable this not necessary error if finaly on our customer the error will always be present!

 

Please could you indicate me the real behavior? Must we follow MCEWizard or Reference Manual?

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1 Solution

Hello,

I can answer to my question! :

I used a discharge generator (1Kv/10Kz) use to check the respect of 61000-4-4.

With that, I generated an Vac Frequency fault where MCEWizard set to disable (Masked).

So This error is really not masked.

The Bug is only on MCEWizard layer: It could not allowing to disable this fault. Or maybe change the IMC102T firmware to can have the possibility to mask this error?

But, my problem now is my board not respect the 61000-4-4! In case of discharge voltage, we generate an AC frequency error.

My Schematic is identical to the evaluation board: Resistor Bridge 1M+1M + 15K with 4.7nF filter.

Could you advice to me a better protection?

View solution in original post

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9 Replies
Krupashankar
Moderator
Moderator
Moderator
500 replies posted 50 likes received 25 likes received

Hi @AG_Serad,

Thanks! for posting in the Infineon Community.

We were able to reproduce the same problem of 3rd bit getting set in PFC_FaultEnable 

Krupashankar_0-1645219605157.png

 

Enabled AC input frequency protection - PFC_FaultEnable = 63

Disabled AC input frequency protection - PFC_FaultEnable = 55

We have contacted our product team regarding the same.

We will get back to you soon!

 

Thanks,

Krupashankar

 
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Hello. 

So currently is the pfc frequency fault is amaskable fault? Because it is what I need! 

Or it is just MCEWizard bug which allowing to mask this fault where the hardware not allow this? 

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Sorry to insist.😥

Could I have a response to my request:

Is the pfc frequency fault is a maskable fault? 

Or

It is just MCEWizard bug which allowing to mask this fault where the hardware not allow this? 

Regards

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Hi @AG_Serad ,

Appreciate the mistake that you've pointed out. We have also internally raised a ticket and informed the product team about this. We will get back to you once the product team validates the issue.

Regards,

Ram

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Hello,

If I understood correctly, at the moment, with firmware version v1.3.3, you can't confirm for me which of these behaviors is applicable at the moment?

This is problematic, my client is waiting for answers and would like to know what to expect.
Currently, does masking the Frequency error have any effect or not?

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Hello,

I can answer to my question! :

I used a discharge generator (1Kv/10Kz) use to check the respect of 61000-4-4.

With that, I generated an Vac Frequency fault where MCEWizard set to disable (Masked).

So This error is really not masked.

The Bug is only on MCEWizard layer: It could not allowing to disable this fault. Or maybe change the IMC102T firmware to can have the possibility to mask this error?

But, my problem now is my board not respect the 61000-4-4! In case of discharge voltage, we generate an AC frequency error.

My Schematic is identical to the evaluation board: Resistor Bridge 1M+1M + 15K with 4.7nF filter.

Could you advice to me a better protection?

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Hello,

I read into the datasheet, but information about this is not clear.

I would know, If it is ok for the PFC if I increase the Vac input capacity (4.7nF -> 47nF or 100nF)

Currently, T=RC = 15K x 4.7nF = 70,5µs

if 47nF  T = 705µs

If 100nF T = 15k x 100nF = 1.5ms

Regarding 50Hz/60Hz after rectifier :  T = 8.33ms.

Until which delay can we set the input AC filter to keep a good working of PFC? I not seen any literature about the setting of this filter?

 

Thank for your back

 

The aim is to avoid bad spike error of 50-60Hz fault - UnderVOltage fault.

But in the documentation, it is not indicated how is used

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Hi @AG_Serad ,

The controller sees multiple zero crossings when electrical fast transients are introduced on the line voltage and that's the reason a frequency error is detected and displayed. As you have rightly mentioned, changing the input capacitor can help filter out the high frequency components. You can try with a 47nF capacitor. 

Increasing this capacitor to a higher value may delay sensing blackout/brownout or increase in input voltage which might affect the performance of PFC or lead to damage if no hardware protections are available.

Hope this helps. Please let us know your findings.

Regards,

Ram

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AG_Serad
Level 4
Level 4
First solution authored 25 replies posted 25 sign-ins

Hi Ram,

Thank for your back.

I take note.

The project is already risky, any change in value is done with the utmost care. I don't want to get other problems by correcting the first problem.

Is 47nF a maximum limit or do we still have a little margin not to disturb the PFC?
If you think this is borderline, I can go down to 22nF or 10nF with the conterpart that we could get again some PFC fault frequency fake.


I prefer get fake fault frequency than get hardware damage...
But if you confirm to me that there will be no problem with 47nF, then I go for it!

 

regards,

Arnaud

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