Hi,

we are implementing a DC motor speed controller using Full H bridge and IR2110 drivers.

The circuit works good for 12V , but if we wish to control a 220V DC load the circuit is not working.

The high side drivers (S1 and S3) of 2 IR2110's are always ON, eventhough we give inputs to S1 and S4 (forward direction).

Gate resistor used is 10ohm and boot strap capacitor of 1uf/10uf is used.

Please help me solve the issue, why at higher DC voltage the circuit is not working

Regards,
Suresh

 

One more point to add, the same circuit if tested in half bridge configuration works fine at 220V DC .

I am not able to figure out the problem, please hlep

 

I am using a PWM frequency of 16kHZ

 

Please post your schematic?

 

I am attaching the circuit please check and let me know what wrong did i do, and whthe circuit is not working for 220V DC

 

You need to use floating 12V supplies for the high side drive to be able to run it at 100% duty cycle.

As you have it now, it will only work if you use PWM with a dity cycle up to around 80-90%.

 

Hi Experimentonomen,

The same circuit is working fine for 12V and 24V load, and the duty cycle supplied in code is from 10% to 90%. Puch Buttons are introduced to increase or decrease the duty cycle for increasing or decreasing the speed of motor respectively.

The question now is why the circuit works for low volatge load but ot high voltage load. And also we verified the low voltage load by switching (removing and connecting 5v supply by hand) the high side switch S1 and by supplying 5V directly to S4 switch. By doing this we see the 12V Fan is running fine. The same is not working for 220V load.

We suspect some hardware mismatch in our circuit, please have a look at the circuit and give us some suggestion

Regards,
Suresh

 

Bad layout can cause issues like this at higher voltages.

Show us some pics, that will make it easier for us to see why it doesent work.

 

Hi Experimentonomen,

You need the pics of the real time hardware construction or just the cisrcuit diagram. I will upload them for you

I have already updated the Motor driver circuit diagram, please check it and tell me if there is any problem in that circuit

Regards,
Suresh

 

This is a useful link also.
http://tahmidmc.blogspot.ca/2013/01/using-high-low-side-driver-ir2110-with.html
Max.

 

Hi MaxHeadRoom,

I have prepared my circuit taking reference of the link what you posted. Please check. the attachment what i uploaded. Please Suggest me what i need to correct.

Regards,
Suresh

 

I have used the similar circuit to the link it shows a small switching diode across the 10Ω gate resistors, but that is most likely not your problem,
The difference is that I turn on the bottom Mosfet completly and PWM the top Mosfet.
Max.

 

Hi MaxHeadRoom,

I have done the same thing. Here's what i have done

I vary PWM duty cycle from 10% to 90% with the help of two push buttons. The PWM frequency i use is 16Khz whoich oi give it directly to High side driver of Ir2110 (Switch S1) and to switch S4 i give directly a logic 1 signal (This is for motor forward direction). What am i missing more?

Regards,
Suresh

 

I am using one of the original IR development boards that were distributed by IR when the IR2110 was released and it uses +15v for the VCC.
Max.

 

The fact that the circuit works at low voltage has very little to do with its working at higher voltages, and more importantly bigger inductive loads (bigger motor).

You also need high speed turnoff diodes parallel to the high side gate resistors, that way you can also increase your gate resistors marginally higher, reducing switching noise.

16Khz is a moderate frequency, but still you should consider using faster diodes than UF4007.

 

Here is what I would try.
Make the boost capacitor only 10 or 12 times the total gate capacitance of your FETs.
Remove the 10k from gate to source on the top FETs.
And/or turn on the bottom FET on the same side as the top one for a few microseconds before you start the PWM. This will charge the boost cap and get it ready for the first cycle.

 

Hi Enggricha,

Please let me know what diodes are faster than UF4007 and should i be using these diodes parallel to high side gate resistor?

This will help me so much

Regards,
Suresh

The fact that the circuit works at low voltage has very little to do with its working at higher voltages, and more importantly bigger inductive loads (bigger motor).

You also need high speed turnoff diodes parallel to the high side gate resistors, that way you can also increase your gate resistors marginally higher, reducing switching noise.

16Khz is a moderate frequency, but still you should consider using faster diodes than UF4007.

 

Hi Ronv,

I have tried your suggestion but it didnt work, please let me know if any changes are to be made

Regards,
Suresh

Here is what I would try.
Make the boost capacitor only 10 or 12 times the total gate capacitance of your FETs.
Remove the 10k from gate to source on the top FETs.
And/or turn on the bottom FET on the same side as the top one for a few microseconds before you start the PWM. This will charge the boost cap and get it ready for the first cycle.

 

Hi Enggricha,

Please let me know what diodes are faster than UF4007 and should i be using these diodes parallel to high side gate resistor?

This will help me so much

Regards,
Suresh

Something like the byv26e, i have used them in the past. Yes the diodes go parallel to the gate resistors. Hope this helps.