Hbridge using IR2110 not working at 220V DC

[suri007]

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.
I am using a PWM frequency of 16kHZ

Note:
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 help


Regards,
Suresh

 

[suri007]

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

 

[suri007]

Any one's out there? please help me with a solution

 

[ronsimpson]

Some ideas to try.

1)You are running very slow compared to what I do. I use MOSFETs.
C4 could be 25V. You could use the same 100uF cap every where. When running fast I use a much smaller boost cap. When the part is used slow the size of the cap must be large. When driving large transistors the cap may need to be increased. You have a pull down resistor on the gate that will also help discharge the boost cap. 2)You could make make the resistor 10x larger.

3) Big capacitors have internal resistance and inductance that keep then from working fast. I would place a 0.1uf cap across every large capacitor. Solder across the IC pins if you want. The small ceramic capacitor will respond very fast but will run out of power soon. The large cap can not respond fast but can keep supplying power for a long time. Try this first.

 

[suri007]

Hi Ronsimpson,

Thanks for your quick response.
1) Regarding your suggestions you said C4 could be 25V, i do not have a capacitor by name C4. Are u point to Cboot capacitor, If so tell me how much value shall i select.

2) I am running PWM at 16Khz so as you said while running fast ypou choose much smaller boot strap capacitor what value should i use with respect to PWM frequency

I will try your suggestion of increasing the pull down resistor to 100kohm as i am presently using 10kohm. I have already places 0.1uf capacitors across all big capacitors.

Please answer my queries

Regards,
Suresh

 

[ronsimpson]

Yes the boost caps do not need to be 65 volts. I was thinking that if the problem is the time is so long that the capacitors discharge then increasing to 100uf/25V will give you 2x more time. You might already have 100uF caps. Changing the resistor will also help.

The IR2110 can not run at 100% or 0% time. The bottom transistor must be on for about 10% of the time to charge the boost cap. Can you try the circuit at 50%.

If I had a oscilloscope I could tell.

 

[suri007]

Hi ronsimpson,

Thanks for the prompt response. Yes i can use 25V/100uF boot strap capacitor and will try with a 100k pull down resistor.

Regarding the duty cycle. I vary it 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). For this i have below queries, please help to answer

1) Is there any dependency of PWM frequency for higher voltages 220V DC. 16kHz is ok or do i need to increase or decrease the frequency?

2) Is there any PWM sequence which i need to follow ?

Regards,
Suresh

 

[suri007]

Hi ronsimpson,

I am waiting for your response to go ahead

Regards,
Suresh