the 400A current will conduct for like a few seconds just to start the motor and after that the motor will just use 200A current...on the spec sheet, it shows that the module can go up to 500A current at Vgs 10V....thats y i thought of just using 1 module only...so does it mean i can just connect the module straight to my motor? I ask someone about whether the module have safety features n he replied this "A voltage headroom is required to allow for voltage overshoots which result from the circuit loop inductances. This is a factor of how good you layout and design is but 55V may not be enough headroom (check)". I dont understand what he means n i cant get in contact with him. hope someone can explain what this means.....another question, do u know how am i suppose to drive the hbridge? i tried looking for IC...so far im not sure which is suitable for this module...so any recommendations?
your using pwm for control, so the mosfets turn on and off many times per second, each time they turn off youll get a huge voltage spike in the wires from the batteries to the controller, due to the wire inductance. these spikes will fry your mosfets and they will go to "on" permanently, and you will be in for a very very wild ride!!!
this exact thing happened to me on a razor scooter with 48v of 60amp discharge lithium polymers and a big cim motor with it's timing advanced 20 degrees.. was fun, but a larger motor and i wouldn't have been able to brake until the circuit board was smoking.
THIS is the most important part of designing something like this, often overlooked by beginners.
there are many things you can do to reduce this... the most simple being choosing higher voltage mosfets so they can tolerate more.
solutions:
the right way is to put computer grade, high ripple amp, low ERS(resistence) electrolytic capacitors across battery leads AS CLOSE TO H-BRIDE AS POSSIBLE.. for 200amps you will need maybe
20 381LQ682M063J452 capacitors.
or 14 381LQ123M050K452 capcaitors
reduce length of wiring to batteries.. this includes series wiring between battieries as well... it adds up!
the "zener" mentioned would be a 1.5ke series transient voltage suppressor.
Vspike=I*sqrt(L/C) 4" 12Gauge=86uH.. 6feet=1.54mH
for me... my controller
(
https://www.diyelectriccar.com/foru...c4420-13763.html?p=100728&posted=1#post100728)
will limit to 50amps (notice banck of capacitors one guy posted!)
my battery lead length is 6 feet... (4 feet is from 35 lithuim polymer cells in series)
say i just had a 1000uF capacitor 0" from the mosfets:
so Vspike=50*sqrrt(.00154/1000x10-6)=62v spike above operating voltage.
in your case, a wild ride!
im using a 10,000uf , 250v capacitor, but its huge so the closest i can put it is 4" from mosfets... so then i also have 2 680uf and 2 30uf metalized film capacitors directly on the fets.
you really should try to make a 50 amp controller for a smaller motor first.. because you WILL burn out your first controller. or, do ALOT more research first on managing transient voltage spikes.
your best bet would be to hook up a pwm chip for the h bridge that can limit the current... absolutely needed for this go kart.. you will pull insane amps for a millisecond on startup!
try out the circuit posted in the url i have above... the chip is like $0.50 and to start you only have to hook up like 5 pins... others are grounded or such.