Hi guys.Im working on a scooter motor that is a 3 phase sensored bldc motor. I have a chinese driver that drives this motor and i want to make my own.I made one with 6 mosfets and 3 ir2103 but it wont work properly(Not enough torques).I was taking a look at the phase voltage of the chinese driver and i found something interesting. The chinese version has no float half bridge during switching.When we want to rotate the motor each time we make one phase high and the other low and the third one is floating,but the chinese driver has always pwm on the phases and it wont let any phases floating.
The other interesting one is that the motor has sensors,but the chinese driver has an oppamp that is connected to the phases and i dont know the reason. Is there any method that i dont know about?If there is would you give me some articles
Thanks.

 

I have the Picmicro Picdem MC LV board for BLDC development, there is explanations and schematics and code, if needed on the Picmicro site.
There is also various app notes on the subject.
Max

 

Hi guys.Im working on a scooter motor that is a 3 phase sensored bldc motor. I have a chinese driver that drives this motor and i want to make my own.I made one with 6 mosfets and 3 ir2103 but it wont work properly(Not enough torques).I was taking a look at the phase voltage of the chinese driver and i found something interesting. The chinese version has no float half bridge during switching.When we want to rotate the motor each time we make one phase high and the other low and the third one is floating,but the chinese driver has always pwm on the phases and it wont let any phases floating.
The other interesting one is that the motor has sensors,but the chinese driver has an oppamp that is connected to the phases and i dont know the reason. Is there any method that i dont know about?If there is would you give me some articles
Thanks.

Is it an opamp really?
Please post the chip's ID.

 

Yes it is lm324.
Do you know anything about this method of driving a bldc?

 

It would be good to see a schematic. Sorry.

 

It would be good to see a schematic. Sorry.

I have not changed the pcb to schematics yet but will do this soon and post here.
If you have any idea about this method i will be thankful to give me any hint.