Hello to all.
First sorry for my poor English.
I have a question.
I would like to switch 200 v and 20A by Mosfet or IGBT and switching frequency is about 60KHZ.
What kind of them, I maen IGBT or Mosfet would you suggest?
Do you know any IC pakage by this information.
Very thank you.
The frequency would suggest a MOSFET is better, the voltage suggests an IGBT would be much
better choice (more robust).
Either way you need great care to protect against the many failure modes a 4kW switching
device faces.... (Not the least is to wear eye protection, 4kW devices fail by exploding violently)
So a proper driver chip is mandatory, as is attention to dV/dt and dI/dt issues, as is opto-isolation
to protect the microcontroller when the device does fail (it will be a learning experience).
I'm fairly confident IGBT's aren't fast enough. 200V for a MOSFET is doable, but the large voltage
swings are a definite issue (surprizing large capacitively-coupled currents flow when a signal jumps
200V in sub-microsecond timescales). At 60kHz you have 8us on average between transistions,
so you need really fast switching to keep switching losses manageable, which places a lot of demands
on circuit layout - you have to keep stray inductance right down.
If you can relax the switching speed constraint it will really help...
I have a 200A switching tig welder (about 4Kw) - it uses 16 large IGBT's. Rectified 240AC is about 340v dc.
Not sure of the frequency, but it works fine.
regards
Allan
allanhurst:
I have a 200A switching tig welder (about 4Kw) - it uses 16 large IGBT's. Rectified 240AC is about 340v dc.Not sure of the frequency, but it works fine.
regards
Allan
Probably < 1kHz, according to an AN from IRF...