need suggestion on BLDC switching circuit.

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iana_nk

Joined: 08 Feb 2007
Posts: 10
Location: Malaysia

19 Mar 2008 11:58 bldc inverter

i'm designing a 3 phase inverter circuit.

it will be applied on 3 phase BLDC motor (AC300020_PB.pdf).

my current inverter circuit i'm designing (inverter_ver1_1.pdf) is able to run the motor but only in very slow speed rotation. For switching frequency 100Hz to 400 Hz the rpm is less than 300rpm.

i'm using Single PWM (Single PWM.pdf) to drive the MOSFET gate with dsPIC4012 microcontroller.

The problem of my design is that the BLDC motor shaft rotation is very low. With less than 400Hz switching frequency, the motor rotatation speed is less than 300 rpm.I'm expecting higher rpm produces by the shaft rotation.

Could anybody suggest me what is the other type of PWM that can be applied to my inverter switch and the frequency ?
Also please correct me if there is any problem with my circuit.

Mosfet model IRF840
gate driver model IR2101.