Hi everyone,

As a university graduation project, I am designing a 3 kW motor driver. For this, I wanted to make a very simple design and make improvements on it. For this reason, I made the design that I shared the schema of, using datasheets and open sources on the internet, and produced the pcb.

The tests I did were very good at the beginning (all of course with no load and small bldc motors). Then I started testing with big motors and under load.

That's when things started to go wrong. After the free-whelling situations and in some other conditions, the 1n4148 diodes and IR2101 ICs started to explode. I've had burnt Atmegas a few times as well.

I wanted to refer to your experiences as to why this happened.

Regards

 

In4148 diodes are signal diodes. Go back to the manufacturers data sheet and use what they recommend. Also 3kw is not a trivial load, given your Vin is less than 100 v.

 

Post photos of your setup. At the power levels you seek, layout and wiring is critical.

Gate drive currents can reach ampere levels - 1N4148 is going to die for sure.

 

I have seen applications on the internet that use both 1n4148 and 1n5819, so I used 4148. So should I try 5819?

I have 3 different boards, it works fine at the beginning, but they are gone after several tryings around 60 V.

The gonners are always atmega chips and diodes

 

Read the datasheet and application notes for the IR2101.

Don't trust random circuits that you see on the internet, so much of this is garbage.
Trust the people that make the parts.

 

I worked for a motor drive manufacturer for a number of years. Testing and finding the weak links is part of the process of development. We had a whole room full of failed designs. A good set of diagnostic tools is imperative. That’s usually beyond the budget of the backyarder. In that case you have to go overboard with the specification of devices to ensure a super safe margin.

 

Your USB and control scheme shares the same ground as the power stage. That's a recipe for disaster. Any load inductive kick can perturb ground enough to cause unplanned ground currents and cause magic smoke to appear. Also makes safe test equipment connections difficult.

 

Your USB and control scheme shares the same ground as the power stage. That's a recipe for disaster. Any load inductive kick can perturb ground enough to cause unplanned ground currents and cause magic smoke to appear. Also makes safe test equipment connections difficult.

Actually, power ground and signal ground are seperated in pcb, they are only connecting in one point but usb ground shares the same plane with usb. Does it cause a problem ?

 

Signal (in this case control) and power grounds on the same PCB plane are generally not a problem, provided they are kept apart. But for high power applications the power stage should be galvanically isolated from anything that 1) comes out of the box and 2) should be touch-safe.

 

Should i replace IR2101 with another gate driver ?

Because the motor that i intend to use is a 72v 40-50 amps motor.

IR2101 has 250mA max output for Ig. This means 125 mA max for each fet.

Another question is, should i use flyback diodes ?

 

I built a similar sized one and used this as a general guide successfully, when I needed isolation, I used the MOC8106 on the LV signal in.
Have you seen this link? http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html
Also SR520 BEMF diodes.

 

I built a similar sized one and used this as a general guide successfully, when I needed isolation, I used the MOC8106 on the LV signal in.
Have you seen this link? http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html
Also SR520 BEMF diodes.

Thanks for all advices !

I have been reading this like two days . I guess i will work on an IR2110 desing.

Thus, this UCC2720 or UCC2721 seems suitable for higher gate charges ?
https://www.alldatasheet.com/datasheet-pdf/pdf/444892/TI1/UCC27210.html

By the way, may i see your design for reference ?

Regards

 

By the way, may i see your design for reference ?

Not near the right PC, will post it later!

 

This is a recent version Picmicro driven.

 

Hi everyone,

As a university graduation project, I am designing a 3 kW motor driver. For this, I wanted to make a very simple design and make improvements on it. For this reason, I made the design that I shared the schema of, using datasheets and open sources on the internet, and produced the pcb.

The tests I did were very good at the beginning (all of course with no load and small bldc motors). Then I started testing with big motors and under load.

That's when things started to go wrong. After the free-whelling situations and in some other conditions, the 1n4148 diodes and IR2101 ICs started to explode. I've had burnt Atmegas a few times as well.

I wanted to refer to your experiences as to why this happened.

Regards

I included the datasheet for the LM25965 if others have trouble finding it In looking at it Using a TO-220 Dissipation, this is what it can output:

 

This is a recent version Picmicro driven.

View attachment 242174

Hey, I have a question.

In this design you use 4148 diodes which have 200 mA max. capacity .

But in tahmid's blog he uses a 1 A capable diode for same purpose.

I know that these two are different designs but if we have up to 1 A gate current, 4148's could handle discharge stuff?

Thanks for all these valuable experiences you share!