Vin RMS calculation in PFC stage of 3.3kW on board charger

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Rakesh_rp
Level 3
Level 3
First solution authored 10 replies posted 10 questions asked

Hi,

I have a doubt in  3.3kW PFC stage  in the given Infineon code for 3.3kW PFC demo board.  The VIN AC RMS voltage is calculation is done by using a digital filter . The Vin sensed ADC reading is  sampled at 30kHz.   The digital filter  function is called every 2.5kHz. The output of filter is considered as average AC voltage . This average voltage is multiplied with 1.111 to get  RMS  AC voltage.  I want to know the cutoff frequency  and  type of filter used.

Below the equation used in code  for filter.  g_U_in   is the ADC reading for Vin Ac sense.

Rakesh_rp_0-1653376223611.png

 

 

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1 Solution
Pranava_YN
Moderator
Moderator
Moderator
100 likes received 500 replies posted 250 solutions authored

Hi Rakesh,

Sorry for the delay in responding. The equations you refer to are the back-to-back low pass filters. The filter factor used (ZK_UIN = T0/T = 1041) is defined in defines.h 

PranavaYN_0-1655095209527.png

http://techteach.no/simview/lowpass_filter/doc/filter_algorithm.pdf  you can refer to this.

Best regards,
Pranava

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4 Replies
Pranava_YN
Moderator
Moderator
Moderator
100 likes received 500 replies posted 250 solutions authored

Hi,

Can you please share the source code you are referring to?

Best regards,
Pranava
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Rakesh_rp
Level 3
Level 3
First solution authored 10 replies posted 10 questions asked

Thanks for replying,

The source code is attached please check.

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Hi,

Please provide  a solution soon. 

Regards

RAKESH

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Pranava_YN
Moderator
Moderator
Moderator
100 likes received 500 replies posted 250 solutions authored

Hi Rakesh,

Sorry for the delay in responding. The equations you refer to are the back-to-back low pass filters. The filter factor used (ZK_UIN = T0/T = 1041) is defined in defines.h 

PranavaYN_0-1655095209527.png

http://techteach.no/simview/lowpass_filter/doc/filter_algorithm.pdf  you can refer to this.

Best regards,
Pranava
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