IR2110 H-Bridge Inverter for Induction Heater
mohiuddinHimel, Mon Jan 02 2012, 07:18PMHi,
I was designing a High Power High frequency Induction Heater inverter. I've choose H-bridge configuration for the inverter
and IR2110 gate drivers to drive the bridge. As the IR2110 is a half-bridge driver i'll use two of them to drive the both sides.
I've done a rough circuit(just drawing). As i dont know much about power electronics i wonder if there is any mistake.
Any kind of advice, recommendation, and any kind of error that should be fixed in my circuit will be highly appreciated!!!
Also i've some questions:
1) what is the use of C3 n how i'll calculate the value?
2) Exactly which back EMF protection Diode should i use as D' ?
3) Do i need to use an opto-isolator for high side nMosfets?
The intended frequency is 150KHz and the Mosfet's are N-type.
PLz help!!
Re: IR2110 H-Bridge Inverter for Induction Heater
Inducktion, Mon Jan 02 2012, 07:27PM
1. I don't know what the purpose of C3 is unfortunately.
2. Most Mosfets have body diodes already built in them. Check the speed of them, if it's faster than say, 200 nS you're fine and don't need an external one. The faster the better.
3. You do not need to use an opto-isolator if the gate driver has high side driving. However, it could be useful to prevent your logic from exploding in case your mosfets fail.
Inducktion, Mon Jan 02 2012, 07:27PM
1. I don't know what the purpose of C3 is unfortunately.
2. Most Mosfets have body diodes already built in them. Check the speed of them, if it's faster than say, 200 nS you're fine and don't need an external one. The faster the better.
3. You do not need to use an opto-isolator if the gate driver has high side driving. However, it could be useful to prevent your logic from exploding in case your mosfets fail.
Re: IR2110 H-Bridge Inverter for Induction Heater
The Lightning Stalker, Mon Jan 02 2012, 09:43PM
That looks pretty sweet to me. I was looking for a single chip solution like this, except that it would drive all four transistors. To answer your questions:
1. C3 is a filter cap for the low side driver driver portion of the chip. It helps isolate the low side driver portion of the chip from any switching noise on the ground and 15V supply rails. It also stores some energy close to the chip for when it demands current to charge the gate of the low side MOSFET. This should be at least a 100nF ceramic type. If you're seeing funny stuff on the low side (or both) gates when the circuit is running, try using bigger ones. If you have to go a lot bigger (above like 1uF), you'll probably be forced to use solid tantalum.
2. Like Dr. Duck says, you may not need any. I think something like the RURG8060 may be a good place to start looking if you need these, but I'm not sure if they're up to snuff at this frequency. You may need something even bigger at really high power levels.
4. The short answer is no. The circuit as drawn works fine assuming nothing goes wrong. I agree with Dr. Duck on this as well, but the place to put the optoisolators, if you use them, would be before the PWM input. It might not be a bad idea to use a couple temporarily during testing to avoid frying your PWM circuitry, but keep in mind they will add delay that may need to be compensated for.
The Lightning Stalker, Mon Jan 02 2012, 09:43PM
That looks pretty sweet to me. I was looking for a single chip solution like this, except that it would drive all four transistors. To answer your questions:
1. C3 is a filter cap for the low side driver driver portion of the chip. It helps isolate the low side driver portion of the chip from any switching noise on the ground and 15V supply rails. It also stores some energy close to the chip for when it demands current to charge the gate of the low side MOSFET. This should be at least a 100nF ceramic type. If you're seeing funny stuff on the low side (or both) gates when the circuit is running, try using bigger ones. If you have to go a lot bigger (above like 1uF), you'll probably be forced to use solid tantalum.
2. Like Dr. Duck says, you may not need any. I think something like the RURG8060 may be a good place to start looking if you need these, but I'm not sure if they're up to snuff at this frequency. You may need something even bigger at really high power levels.
4. The short answer is no. The circuit as drawn works fine assuming nothing goes wrong. I agree with Dr. Duck on this as well, but the place to put the optoisolators, if you use them, would be before the PWM input. It might not be a bad idea to use a couple temporarily during testing to avoid frying your PWM circuitry, but keep in mind they will add delay that may need to be compensated for.
Re: IR2110 H-Bridge Inverter for Induction Heater
Marko, Mon Jan 02 2012, 10:15PM
Yep, there is, a parallel LC fed by a voltage fed inverter is a certain instant mosfet death. You should look into "LCLR" , "Series" or current-fed topology IH's.
For all but the current fed ones, you're going to need some sort of feedback loop to keep your work coil current at safe levels when the workpiece is not present.
This is a simple project you might want to have a look at:
Marko, Mon Jan 02 2012, 10:15PM
Any kind of advice, recommendation, and any kind of error that should be fixed in my circuit will be highly appreciated!!!
Yep, there is, a parallel LC fed by a voltage fed inverter is a certain instant mosfet death. You should look into "LCLR" , "Series" or current-fed topology IH's.
For all but the current fed ones, you're going to need some sort of feedback loop to keep your work coil current at safe levels when the workpiece is not present.
This is a simple project you might want to have a look at:
Re: IR2110 H-Bridge Inverter for Induction Heater
Dr. ISOTOP, Tue Jan 03 2012, 05:02AM
Bleh, feedback is overrated; mine ran open-loop and never blew up
The IR2110 is probably not going to drive transistors big enough for induction heating.
Also, you should look into using a matching transformer, or LCLR.
Dr. ISOTOP, Tue Jan 03 2012, 05:02AM
Dr. Pork wrote ...
For all but the current fed ones, you're going to need some sort of feedback loop to keep your work coil current at safe levels when the workpiece is not present.
For all but the current fed ones, you're going to need some sort of feedback loop to keep your work coil current at safe levels when the workpiece is not present.
Bleh, feedback is overrated; mine ran open-loop and never blew up
The IR2110 is probably not going to drive transistors big enough for induction heating.
Also, you should look into using a matching transformer, or LCLR.
Re: IR2110 H-Bridge Inverter for Induction Heater
mohiuddinHimel, Fri Jan 06 2012, 10:59PM
I really like your circuit! it made my life lot more easier dude! even now i want to try this one first!! but several questions
1) Can i use 1N4937 diodes as "fast didoes" in your circuit? because it is the fastest possible diode in my country.
2) Is it mandatory that both of the inductors have to have same value? i'll make them with ferrite toroids and wound enamel insulated wire around them.
3) for the power supply can i use 24VDC (220 Vac to 12Vac transformer, 400 watt, rectified and voltage doubled by two big caps)?
4) What determines the frequency of this oscillator?? simple f=1/(2pie*sqrt-root(LC)) ?
mohiuddinHimel, Fri Jan 06 2012, 10:59PM
Dr. Pork wrote ...
This is a simple project you might want to have a look at:
This is a simple project you might want to have a look at:
I really like your circuit! it made my life lot more easier dude! even now i want to try this one first!! but several questions
1) Can i use 1N4937 diodes as "fast didoes" in your circuit? because it is the fastest possible diode in my country.
2) Is it mandatory that both of the inductors have to have same value? i'll make them with ferrite toroids and wound enamel insulated wire around them.
3) for the power supply can i use 24VDC (220 Vac to 12Vac transformer, 400 watt, rectified and voltage doubled by two big caps)?
4) What determines the frequency of this oscillator?? simple f=1/(2pie*sqrt-root(LC)) ?
Re: IR2110 H-Bridge Inverter for Induction Heater
Marko, Fri Jan 06 2012, 11:37PM
1. 1N4937 should work, yes.
2. Just wind the same number of turns on both of them! Use yellow toroids from PC power supplies. Do not use ferrite toroids.
3. Should work, providing your doubler caps are large enough.
4. What you said - and the L is inductance of the work coil, not chokes as some people think. In my case the circuit resonates with a 4uF cap at about 100kHz.
Marko
Marko, Fri Jan 06 2012, 11:37PM
1. 1N4937 should work, yes.
2. Just wind the same number of turns on both of them! Use yellow toroids from PC power supplies. Do not use ferrite toroids.
3. Should work, providing your doubler caps are large enough.
4. What you said - and the L is inductance of the work coil, not chokes as some people think. In my case the circuit resonates with a 4uF cap at about 100kHz.
Marko
Re: IR2110 H-Bridge Inverter for Induction Heater
Patrick, Sat Jan 07 2012, 03:00AM
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
Patrick, Sat Jan 07 2012, 03:00AM
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
Re: IR2110 H-Bridge Inverter for Induction Heater
Daedronus, Sat Jan 07 2012, 03:36AM
Makes sure they don't turn on by accident while the driver is unpowered?
It doesn't take much to turn on a mosfet, just touching the gate is enough.
Daedronus, Sat Jan 07 2012, 03:36AM
Patrick wrote ...
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
Makes sure they don't turn on by accident while the driver is unpowered?
It doesn't take much to turn on a mosfet, just touching the gate is enough.
Re: IR2110 H-Bridge Inverter for Induction Heater
Dr. ISOTOP, Sat Jan 07 2012, 03:57AM
It's a pulldown resistor, there largely as a safety measure.
If the driver fails you don't want the gate to stay charged and make the transistor go boom.
Dr. ISOTOP, Sat Jan 07 2012, 03:57AM
Patrick wrote ...
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
why is there a 1k resistor from gate to emitter? some of my IC's datasheets show them being used too.
It's a pulldown resistor, there largely as a safety measure.
If the driver fails you don't want the gate to stay charged and make the transistor go boom.
Re: IR2110 H-Bridge Inverter for Induction Heater
Patrick, Sat Jan 07 2012, 07:43AM
Excellent.... so 1k is a good value for this? some of my datasheets show it, but they print no value.
Patrick, Sat Jan 07 2012, 07:43AM
Excellent.... so 1k is a good value for this? some of my datasheets show it, but they print no value.
Re: IR2110 H-Bridge Inverter for Induction Heater
mohiuddinHimel, Sat Jan 07 2012, 12:08PM
Oright then i have to collect old PC power supplies to get these toroids. If you can tell me the core-material or type of the toroids i would simply buy it from market and that would be waaay more convenient to me.
can i use IR G4PC50UD IGBT instead of mosfets and 20V zeners to maintain gate to emitter voltage?
here is the datasheet:
mohiuddinHimel, Sat Jan 07 2012, 12:08PM
Dr. Pork wrote ...
1. 1N4937 should work, yes.
2. Just wind the same number of turns on both of them! Use yellow toroids from PC power supplies. Do not use ferrite toroids.
3. Should work, providing your doubler caps are large enough.
4. What you said - and the L is inductance of the work coil, not chokes as some people think. In my case the circuit resonates with a 4uF cap at about 100kHz.
Marko
1. 1N4937 should work, yes.
2. Just wind the same number of turns on both of them! Use yellow toroids from PC power supplies. Do not use ferrite toroids.
3. Should work, providing your doubler caps are large enough.
4. What you said - and the L is inductance of the work coil, not chokes as some people think. In my case the circuit resonates with a 4uF cap at about 100kHz.
Marko
Oright then i have to collect old PC power supplies to get these toroids. If you can tell me the core-material or type of the toroids i would simply buy it from market and that would be waaay more convenient to me.
can i use IR G4PC50UD IGBT instead of mosfets and 20V zeners to maintain gate to emitter voltage?
here is the datasheet:
Re: IR2110 H-Bridge Inverter for Induction Heater
Marko, Sat Jan 07 2012, 12:58PM
Hi,
IIRC the core is the material 26 (Amidon/CWS) , probably has other names I don't know of, and is usually in a form of yellow-white toroid. I'm not sure if you can find those in typical local shops though! (for most people, it would be more convenient to pull them out!)
I wouldn't recommend using igbt's, their CE voltage drop is hard on the diode feedback thing as off voltage on the gate starts to get dangerously near threshold voltage... some people apparently got it working though you would need some low drop (prefferably schottky) diodes and still not push the voltage too high, perhaps up to 100V max.
IRFP260's are choice mosfets for this. The problem is that at higher voltages not only the ON resistance gets higher, but the diodes will tend to need to be bigger and have much greater forward voltage drop.
I used IRFP150's in my circuit, which enabled it to run up to 30V (my caps wouldn't take much more anyway).
Marko
Marko, Sat Jan 07 2012, 12:58PM
Hi,
IIRC the core is the material 26 (Amidon/CWS) , probably has other names I don't know of, and is usually in a form of yellow-white toroid. I'm not sure if you can find those in typical local shops though! (for most people, it would be more convenient to pull them out!)
I wouldn't recommend using igbt's, their CE voltage drop is hard on the diode feedback thing as off voltage on the gate starts to get dangerously near threshold voltage... some people apparently got it working though you would need some low drop (prefferably schottky) diodes and still not push the voltage too high, perhaps up to 100V max.
IRFP260's are choice mosfets for this. The problem is that at higher voltages not only the ON resistance gets higher, but the diodes will tend to need to be bigger and have much greater forward voltage drop.
I used IRFP150's in my circuit, which enabled it to run up to 30V (my caps wouldn't take much more anyway).
Marko
Re: IR2110 H-Bridge Inverter for Induction Heater
mohiuddinHimel, Sat Jan 07 2012, 06:00PM
hi
now i think PC power supply was a better idea :|
Um gonna try both the IRFP150 n IRFP250 :)
mohiuddinHimel, Sat Jan 07 2012, 06:00PM
Dr. Pork wrote ...
Hi,
IIRC the core is the material 26 (Amidon/CWS) , probably has other names I don't know of, and is usually in a form of yellow-white toroid. I'm not sure if you can find those in typical local shops though! (for most people, it would be more convenient to pull them out!)
I wouldn't recommend using igbt's, their CE voltage drop is hard on the diode feedback thing as off voltage on the gate starts to get dangerously near threshold voltage... some people apparently got it working though you would need some low drop (prefferably schottky) diodes and still not push the voltage too high, perhaps up to 100V max.
IRFP260's are choice mosfets for this. The problem is that at higher voltages not only the ON resistance gets higher, but the diodes will tend to need to be bigger and have much greater forward voltage drop.
I used IRFP150's in my circuit, which enabled it to run up to 30V (my caps wouldn't take much more anyway).
15
Marko
Hi,
IIRC the core is the material 26 (Amidon/CWS) , probably has other names I don't know of, and is usually in a form of yellow-white toroid. I'm not sure if you can find those in typical local shops though! (for most people, it would be more convenient to pull them out!)
I wouldn't recommend using igbt's, their CE voltage drop is hard on the diode feedback thing as off voltage on the gate starts to get dangerously near threshold voltage... some people apparently got it working though you would need some low drop (prefferably schottky) diodes and still not push the voltage too high, perhaps up to 100V max.
IRFP260's are choice mosfets for this. The problem is that at higher voltages not only the ON resistance gets higher, but the diodes will tend to need to be bigger and have much greater forward voltage drop.
I used IRFP150's in my circuit, which enabled it to run up to 30V (my caps wouldn't take much more anyway).
15
Marko
hi
now i think PC power supply was a better idea :|
Um gonna try both the IRFP150 n IRFP250 :)
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