[SOLVED] 80 V 50 A charger with PFC if ac mains input cuts what happens?

[oyorutken]

Hello,
I am trying to fix and decrease our charger failures.
This charger has an input fuse (AC Mains 3 Phase 50hz) and during charging battery if this fuse is closed manually
would it harm to electronics of chargers, it has input filter caps a pfc circuit and after a smps with constant current.
I am working on a circuit which will detect ac input cut event and immediately it will send stop charge command to charger,
What do you kindly thing is it necessary ? or it can save some failures?
Thank you very much

 

[cupoftea]

Yes definitely you should have input undervoltage lockout.
Also, inrush protection for mains connection.
Howcome you have PFC when you have three phase input?....its not usually needed for 3 phase....just use a 6 diode rectifier...gives pretty good PFC.

 

[KlausST]

HI,

in case you use a microcontroller:
It´s almost standard in my microcontroller designs to "watch" the power supply.
In simples case I just have a power supply monitor (for 3.3V for example) that asserts a RESET when power is too low. This RESET may be used to stop the microcontroller , but also the disable other parts of the electronics,( like a MOSFET driver for example).

But it could also watch about mains to get an "early alert" to smoothly power down everything, save states / variables in an EEPROM... and so on.

It depends on "what could happen ... if". If you fear to casue a n erroneous short circuit on the battery ... and risk overheat, explosion, fire ... then you definitely should add some protection.

Klaus

 

[oyorutken]

Yes definitely you should have input undervoltage lockout.
Also, inrush protection for mains connection.
Howcome you have PFC when you have three phase input?....its not usually needed for 3 phase....just use a 6 diode rectifier...gives pretty good PFC.

Thank you for answer, it is actually a forklift battery charger (lifepo4 80v 350ah) and it has multiple 50 amp modules, and totally it can produce 100 amps or more. Its input is 3 phase and has pfc, i have seen some other types and they also have pfc, it changes its output (constant current output) by the demand from bms (can-bus), so i think changing demand makes pfc necessary.
It has already a input and output inrush current protector (im not sure but i have seen some relays bypassing resistors) i have 0 experince in pfcs and
I can not imagine in my mind what happens when the power is cut immediately.

 

[oyorutken]

HI,

in case you use a microcontroller:
It´s almost standard in my microcontroller designs to "watch" the power supply.
In simples case I just have a power supply monitor (for 3.3V for example) that asserts a RESET when power is too low. This RESET may be used to stop the microcontroller , but also the disable other parts of the electronics,( like a MOSFET driver for example).

But it could also watch about mains to get an "early alert" to smoothly power down everything, save states / variables in an EEPROM... and so on.

It depends on "what could happen ... if". If you fear to casue a n erroneous short circuit on the battery ... and risk overheat, explosion, fire ... then you definitely should add some protection.

Klaus

Thank you for answer sir, this charger is produced by a Chinese company for charging forklifts, battery has a bms and they constantly communicate via can bus (battery sends soc and demand current), and even input mains are cut it continues to work for 5-10 seconds with capacitor remaining charge.
These chargers are failing and making a huge expense for us. I believe there are two reasons
1. DC side - pulling the charger cable off from battery during charging (no magnetic lock)
2. AC side - turning it off from fuses during charging (some people say it wont harm charger) but i am not sure, i can not imagine what happens in pfc circuit during that time.

 

[oyorutken]

Hello,
I am trying to fix and decrease our charger failures.
This charger has an input fuse (AC Mains 3 Phase 50hz) and during charging battery if this fuse is closed manually
would it harm to electronics of chargers, it has input filter caps a pfc circuit and after a smps with constant current.
I am working on a circuit which will detect ac input cut event and immediately it will send stop charge command to charger,
What do you kindly thing is it necessary ? or it can save some failures?
Thank you very much

Thank you very much who read this and thought about it,
i discovered charger unit HAS this circuit internally, i tried to cut power during a test and it internally sends a stop command.
Thank you all.
regards