EEVblog® Electronics Community Forum
Electronics => Power/Renewable Energy/EV's => Topic started by: Faringdon on August 07, 2021, 01:56:35 pm
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Hi,
Do you know what is the inrush current into a Nissan Leaf on-board EV charger?
(or any other electric car)
Consider worst case....eg connection to mains at mains peak.
This must be known, because otherwise how do they spec the relays in the charge boxes?
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This 35A relay offers 50000 operations when switched with 35A in it...
https://www.panasonic-electric-works.com/cps/rde/xbcr/pew_eu_en/ds_hes_en.pdf (https://www.panasonic-electric-works.com/cps/rde/xbcr/pew_eu_en/ds_hes_en.pdf)
Inrush (at mains peak) into a typical SMPS is likely to be 80A.
So what is the lifetime of this relay with this 80A in the contacts?
Due to contact bouncing, the full 80A at mains peak is likely to be experienced every time it switches.
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Inrush (at mains peak) into a typical SMPS is likely to be 80A.
Are typical high power PFC circuits utter trash?
A PFC doesn't require a large input capacitor and can limit inrush current with active control. There is no rush at all with PFC, it can just fill up the DC link at a leisurely pace and low peak current and then turn on the power supply.
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There's a precharge relay that closes before the main relay. Thus, the main relay experiences next to zero inrush while the precharge relay only sees a peak current limited by the precharge resistor.
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A PFC doesn't require a large input capacitor and can limit inrush current with active control. There is no rush at all with PFC, it can just fill up the DC link at a leisurely pace and low peak current and then turn on the power supply.
PFC by itself does not prevent inrush current. Until output capacitor charges to input voltage, it can do nothing about current flowing.
EDIT: But since battery the in the car is under high voltage to begin with, it might be not a problem which needs to be dealt with.
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Thanks, yes..
And as we know, they do use relay switched inrush resistors.....but these are only some 5 Ohms...and so peak inrush can be up to 80A....even more if mains is 265VAC and it gets connected at mains peak.
There's a precharge relay that closes before the main relay. Thus, the main relay experiences next to zero inrush while the precharge relay only sees a peak current limited by the precharge resistor.
Thanks, you mean in the electric vehicles on-board charger?...how do you know this?.....for every electric car on the market?....for every future electric car that will get on the market?.....admittedly that would be great if correct.......but how do you know they do this?....ive searched the web for it and cant find anything.