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short circuit protection for battery charger protection

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Full Member level 4
Aug 23, 2014
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Currently I am working on a battery charger for electric 2 wheeler.
The charger is an off board charger (kept outside the vehicle while charging).
Power rating is roughly 720 W i.e. 60V ,12 A

The dc-dc section of the battery charger is LLC HB converter with secondary side synchronous rectification. It is a digitally controlled by a c2000 processor. I am using INA180A4IDBVR for output current sensing through a shunt. Kindly let me know how to implement short circuit protection in this product. I have read about following methods that can be implemented digitally.

1) Increase the operating switching frequency beyond the resonant frequency.

2) Limit the duty cycle under 10 percent .

3) Disconnect the charger from the mains .

Is there any method apart from the above that can be implemented

S/cct protection you do with current sense transformer in the bridge, and you put its output into comparator with hysteresis.
Why do you not choose an ICE2 LLC controller that has a s/cct function?

I am already sensing the primary current through a CT. But my question is how should i protect against output short circuit.

The present design is based on digital control instead of an analog IC.


Might a cheap automotive circuit breaker do the job, if sized appropriately?

For a "screwdriver short" fault scenario it might. For a failed-component /
-connection, a fuse would drive repair more authoritatively (why you still
see them as as a safety backstop despite all the "smarts" in "smart power").
The primary CT will protect against output s/cct...via txformer coupling.
Ok..But what is the action should i take if the primary CT output exceeds a particular threshold during short circuit.??
Will the following help

1) Increasing the switching frequency higher than resonant frequency

2) Limiting the duty cycle below 10 percent

3) Disconnect the charger from the mains

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