BLDC motor Consuming very high current on NO loaded condition

Projects General Guidance
1

Hi,

I am using Arduino Mega to control a BLDC motor with Hall sensor who's maximum speed is about 30,000Rpm with the supply of 12VDC.

It is a low inductance motor with the phase to phase inductance of ~4uH.

I am using TI made DRV2303H Mosfet driver, and the PWM of 31.250KHz is given to Driver from Arduino Mega.

I am able successfully run the motor to the full speed. But the motor is consuming very high current (About 20A) on No loaded condition. The motor datasheet says the no load current is 1.4Amps.

I have attached the Phase voltage plot. I could see a lot of high voltage pulses on the output (During PWM High). I hope if i could reduce the voltage spikes on output the current should be reduced.

Any suggestions to sort the issue?

Shivu

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2

No schematic?

3

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Inlined for convenience. Pretty pictures, for sure.

Schematics & info on the actual motor used would be more useful.

Anything that gets hot? Especially of interest is components that get hot but shouldn't. That 240W (20A x 12V) has to go somewhere!

4

A BLDC motor either must be free running, steered by its hall sensors, or with controlled current. The low coil resistance requires a dramatic duty cycle reduction with small load or speed. The data sheet tells the maximum allowed current, not what the motor will draw in an uncontrolled environment.

A simple solution is a ready made BLDC motor module, or you understand and implement that control in your program.