Hi all,
I am designing a H-Bridge inverter for induction furnace application. My DC bus voltage is 400 V and current is 15 A.
To start with I used 12 V supply to test my H-Bridge inverter connected to load resistor of 10 Ohm.
I used IXFH26N50 from IXYS semiconductor for H-Bridge and the MOSFETS are driven by two IR2110 drivers.
But during turn-on of the MOSFETS, I could see excessive ringing at both the output terminals of the H-Bridge with respect to ground and also on the MOSFET gates.
I have used shielded twisted wires to connect driver terminals to MOSFET to reduce the wire inductances and 1000µF capacitor on the DC bus, but no appreciable reduction in ringing noise amplitude.
In many papers and application notes it is mentioned that, this ringing is due to gate to drain capacitance and can be suppressed with the use of ferrite beads near gate terminal.
But I have not tried with ferrite beads, will ferrite beads suppress this ringing?
Will changing the MOSFET be a solution? If so help me to choose a MOSFET that could have lesser switching noise and suitable for induction heating application.
Please help.
I am designing a H-Bridge inverter for induction furnace application. My DC bus voltage is 400 V and current is 15 A.
To start with I used 12 V supply to test my H-Bridge inverter connected to load resistor of 10 Ohm.
I used IXFH26N50 from IXYS semiconductor for H-Bridge and the MOSFETS are driven by two IR2110 drivers.
But during turn-on of the MOSFETS, I could see excessive ringing at both the output terminals of the H-Bridge with respect to ground and also on the MOSFET gates.
I have used shielded twisted wires to connect driver terminals to MOSFET to reduce the wire inductances and 1000µF capacitor on the DC bus, but no appreciable reduction in ringing noise amplitude.
In many papers and application notes it is mentioned that, this ringing is due to gate to drain capacitance and can be suppressed with the use of ferrite beads near gate terminal.
But I have not tried with ferrite beads, will ferrite beads suppress this ringing?
Will changing the MOSFET be a solution? If so help me to choose a MOSFET that could have lesser switching noise and suitable for induction heating application.
Please help.
Gate stoppers have to be mounted right on the fet (or as close as practical). Values... depends on your switching speed but probably around 150 ohm. Also make sure there is no cross conduction of the fets (that there is enough dead time)
(I'm no expert on power H bridges beyond the basic theory)
(I'm no expert on power H bridges beyond the basic theory)
Thanks for your reply.
I am using 33 ohm resistor with a diode in parallel for faster turn off.
But I guess 150 ohm might result is greater switching loses due to slower switching. I will try with 150 ohm also.
Is there any other way to reduce ringing?
Will changing the MOSFET help to reduce ringing amplitude?
I am using 33 ohm resistor with a diode in parallel for faster turn off.
But I guess 150 ohm might result is greater switching loses due to slower switching. I will try with 150 ohm also.
Is there any other way to reduce ringing?
Will changing the MOSFET help to reduce ringing amplitude?
Whats your switching speed ?
I would doubt changing the FET type would do much tbh. Make sure that any high current returns are correctly routed and that other parts of the circuit don't share and use these returns as "their" ground. Just like in audio, you have to be careful how and where the current flows so it doesn't alter or contaminate other parts of the circuit.
I would doubt changing the FET type would do much tbh. Make sure that any high current returns are correctly routed and that other parts of the circuit don't share and use these returns as "their" ground. Just like in audio, you have to be careful how and where the current flows so it doesn't alter or contaminate other parts of the circuit.
Hope the added gate resistors help, but if it does not:
What controller are you using?
What is the switching speed?
What is the dead time?
Mooly asked already. This is vital information. Can you share?
IR2110 is not that powerful. You are driving pretty hefty mosfets with it (just wondering about the large heatsinks here)...
What controller are you using?
What is the switching speed?
What is the dead time?
Mooly asked already. This is vital information. Can you share?
IR2110 is not that powerful. You are driving pretty hefty mosfets with it (just wondering about the large heatsinks here)...
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