HomeFAQ1Kw Motor Driver

1Kw Motor Driver

I am building 1Kw Motor Driver with following specification

max voltage 48V
max Current 25Amps
Motor to run BLDC motor

Components used
- Mosfet IRF3205
- Driver Ir2101
- Boost Cap 1uF Box type
- Gate Resistance 11 ohm
- Micro used ATMega8
- PWM on low Switches only
- Switching frequency 8 KhZ
- Heat sink area is 10 time the mosfet area
- Ambient Temperature is 30 Degree Celsius

Problem :->Heat sink gets heated up to 65 Degree Celsius @ 3 Amps, 24 V only, after running it for 10 mins,
which is very high

Tried few things
- Changed drivers with higher current rating IR2181 but no change in outcome
- Changed Gate resistance to 22ohm but no change
- Changed gate resistance to 5 ohm but no change
- Changed switching frequency to 4kHz => temp increasing to 70 degree Celsius + lot noisy operation

One problem which I have discovered is with the hall sensor placement. if that is not correct/accurate then it caused problem. since I was trying to run the home made motor (24 slot 28 pole) which might have inaccuracies in sensor placement, might be the root cause of the problem.

I changed it with some other motor and things seems fine for the moment(48 V 3 Amps, NO heating) but the driver is getting little hot after some time which made one of the micro pin(high side) bad.

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