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IR2110 Mosfet/IGBT Gate Driver - Three phase inverter for BLDC motor - help needed

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karthick89

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Friends,

my project: speed control of BLDC motor (square wave BLDC)...

my motor(load) specifications are: 24VDC(for inverter) 0.25HP 3000RPM and by calculations it shows current rating will be 8Amp
so the inverter should be designed for this specifications...

with the help of datasheet i designed the mosfet gate driver circuit, i have attached my circuit diagram here...

i have soldered this circuit in board....

for gate pulses, i used arm processor, 120 deg mode, given in correct sequence...

when i checked this circuit with just resistance load 1k ohm, the inverter output was step wave, only 10V peak to peak,
whatever input given to inverter, i got only 10V not exceeding it..

when i connected motor to this circuit, motor started at very less speed, and after few seconds, mosfet got burnt..


i checked this forum for the circuit, i found many corrections in my circuit....

so, i attached what i did in my circuit

friends, please guide me in solving my problem...
 

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A couple of things which may solve the problem you describe:
1. You need to place resistance in series with the mosfet gates for current limiting - use ~22ohm
2. Place a ~2.2k resistor from the mosfet gate to ground.

- - - Updated - - -

Also noticed you have the polarities "+" and "-" for the bootstrap capacitors on your diagram- does this mean you are using electrolytics? The bootstrap capacitors should be low ESR (usually ceramic) since you may have problems generating high side voltage at very low or very high duty cycles (also possible cause for your problem if using electrolytic, since gates won't be turned on fully)
 
hi, thanks for your response....

i will check with resistances you told in lab tomorrow...

and about capacitors, how to find whether it is Electrolytic capacitor or low ECR capacitor?

i have attached a picture of the capacitor i use with this...

thank you..... i will update my result soon...
 

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those capacitors are electrolytic capacitors only..... and also i tried as what you said with resistances... but no output across the phases....
 

check your diagram very well pic 5 of IR2112 should'nt go to ground it suposed to go A,B,orC before your bootstrap will work.
 

You forgot to use Gate to source resistor 1K which is very important for each Mosfet
 

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