PFC with ICE3PCS01G catastrophic failure

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Rafa
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First reply posted First question asked Welcome!

Hi,

we are developing an AC three phase induction motor driver with a PFC stage in front. We have basically copied the “EVAL_2.5KW_CCM_4PIN”  for PFC stage with minor changes.  See the schematics below and also attached pdf file.

PFC Schematics.GIF

We are using a non-isolated gate driver (1EDN7550) and 10mR current sense resistor and 350VDC bus with maximum load of 6A.  We have 5 prototypes for beta testing at customer facilities and they all have been working fine until recently. One of them came back yesterday with extensive damages and burning in PFC stage. The 10mR current sense resistor is completely evaporated, D5, D9 and Q3 are all shorted and there is huge sign of arcing between vias of sense resistor and chassis ( chassis is connected to PE and has 7mm distance to the bottom of the board). Also, R110 (Vsens first resistor) is burned.  Could you please help me to understand what could have gone wrong and ways to improve the design? Any suggestion is highly appreciated.

Thanks for your attention

Ramin Fardi

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1 Solution
Guruprasad_A
Moderator
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25 likes received 250 sign-ins 50 solutions authored

Hello,

Most of the series components have failed due to high input current, which may be the effect of failed MOSFET.

  • Power rating are similar to refence board EVAL_2.5KW_CCM4PIN, Sense resistor should be 5mR.
  • Gate driver used is having lower source and sink current compared to driver used in reference.

Gate driver and sense resistor are mostly the reasons for MOSFET failure. And other reasons includes rise in temperature of MOSFET and saturation of Inductor.

To address this, Kindly change sense resistors and driver. Check temperature of MOSFET and Inductor while operating. Ensure temperature are within limit.

 

Regards,

Guruprasad A

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3 Replies
Guruprasad_A
Moderator
Moderator
Moderator
25 likes received 250 sign-ins 50 solutions authored

Hello,

Most of the series components have failed due to high input current, which may be the effect of failed MOSFET.

  • Power rating are similar to refence board EVAL_2.5KW_CCM4PIN, Sense resistor should be 5mR.
  • Gate driver used is having lower source and sink current compared to driver used in reference.

Gate driver and sense resistor are mostly the reasons for MOSFET failure. And other reasons includes rise in temperature of MOSFET and saturation of Inductor.

To address this, Kindly change sense resistors and driver. Check temperature of MOSFET and Inductor while operating. Ensure temperature are within limit.

 

Regards,

Guruprasad A

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Hi,
Thanks a lot for the prompt response. I will change the sense resistor and the gate driver according to the Eval board. However, regarding the gate driver, we do not have an isolated DC voltage on board. The gate driver’s VCC is derived from 230V AC by a non-isolated off line buck converter. Do you think this fact could cause any problem?

Regards/Ramin

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Guruprasad_A
Moderator
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25 likes received 250 sign-ins 50 solutions authored

Hi @Rafa ,

Typically it should not make any issue. Make sure that buck converter voltages are in the limit and grounding connections are proper . 

Regards,

Guruprasad A

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