Issue in Sensored BLDC motor driving

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello All,

Good Morning!!!

I have developed 12V and 24V BLDC motor driver with max current upto 20A

The driver is working fine. The efficiency is good.

Sometimes it is giving the issue. Sometimes once I turned on the power then suddenly blast happens and current reaches 70-80A.

Please suggest me remedy over this issue. My design is still not getting approved just because of this issue.

Please let me know if you will need more information on it.
 
There's power supply sequencing and for that matter, what does the uP (likely) that it;s connected to do as it's powering up?
Is their adequate bypassing? Is the hardware designed to prevent all of the devices to be on at the same time? Is the FETS at anytime being operate in the linear region?

Just things to look into.
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
There's power supply sequencing and for that matter, what does the uP (likely) that it;s connected to do as it's powering up?
Is their adequate bypassing? Is the hardware designed to prevent all of the devices to be on at the same time? Is the FETS at anytime being operate in the linear region?

Just things to look into.
Hello keep,

Once power up the uP does the normal operation. i.e. check hall positions and turn on the respective mosfte's .

What is adequate bypassing?
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello MaxHeadRoom,

I am doing it in the same way. Still Mosfets are blasting during power up. It is randomly happening during power On.
 

shortbus

Joined Sep 30, 2009
9,637
I am doing it in the same way. Still Mosfets are blasting during power up. It is randomly happening during power On.
Do all of your uP inputs/outputs have a real value when they are starting up? Either tied to ground or voltage through a high value resistor, or are they 'floating'? If they are 'floating' they could give any signal they want at start up.
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello, The 6 micro controller signals which are tied up high.

Please help me to resolve this issue. I am awaiting for your reply.
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello Alec_t,

As per the circuit diagram, I had posted earlier.
What I think the circuit can not be changed. One thing is observable here.
If I pull up the upper MOSFET lines with 5V in between micro controller and ULN2003 IC (U2). Does this will work for me?
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello Alec_t,

Thank you so much. The sometimes power blast issue has been resolved.

Thank You so much for your help.

One more issue is raised.
The first situation is,
Suppose, motor is at full load and POT (Throttle) is at maximum and then motor is trying to start and somebody picks rotor by hand then motor is stopping. It should reach 20 A and then it should stop as 20A set as current protection range. But it is stopping at 1 A or 2 A of current.

The second situation is if motor is at full load i.e. at 19A (as 20A is shut down of motor). Then I stopped the supply. Then I again starts the supply, at that instance the motor is running and reaching to 19A.

The third situation is, if motor is running at 19A i.e full load and I stopped the supply and increased some more load using dynamo meter and then I started the supply at that time also it is running and once reach 20A it stopps.

The second and third situation is good. But at first situation, motor actually should run. Once it would reach 20A it should stop.

What could be the case?
 

Thread Starter

RenesasT1

Joined Jul 6, 2017
107
Hello Alec_t,

My power supply is not cutting. It is a huge power supply of max dc voltage 100V and max current is of 60A.

Situation second is ok. In situation first there is problem.

Also situation 3 is not OK. If I increase the load from dynamo meter and then turned on the motor then also there is stopping at 7-10 A. But the actual current cut off is at 20A.

Please suggest.
 
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