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Thanks FvM. Tried your function and not only is it foolproof and always gives the correct result but it also reduced the execution time from 0.5us to 0.36us. Being an electrical engineer, not studying basic C programming when I had the time always comes back to bite me in the @$$...
Just give...
After spending the past few days getting the fixed point library to actually build, I was shocked to see that there are only Add and Subtract functions in the libq.h
First question is why no Multiply and Divide?
After playing around, I did get the the following code to multiply and give the...
Just got up and understood the importance of taking exact values from graphs.
So Etotal at 5A is 2.7mJ and Vce is 1V.
So the initial 30W reduces to 15W.
So can I safely declare that the IGBT under consideration, FGA25N120 dissipates 15W when average Ic is 5A at 4kHz switching frequency?
Now...
Klaus the issue is the IGBT...30W. For MOSFETS its 3W.
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OK just saw the 18x3 error.
But are you saying that my calculations for IGBT losses are correct, and even a tiny 3-5A current through IGBTS require monster heatsink.
The switching loss itself ruins it all. Add to it...
I just went over the concept of dissipation and thermal resistance calculations for MOSFETs and opened a few IGBT datasheets do repeat the exercise for IGBTs.
Now for MOSFETS, at 24V and 35A with 20kHz switching, I got losses of say 3W max for many cheap MOSFETS (RDSon about 2mOhm). So even a...
Klaus, the first part I understand that low side is on for a LONG time and the bootstrap gets nicely charged.
But duty cycle, according to me won't make a difference here as even when the high side switch turns off during PWM, the switch below it is also off, meaning that bootstrap is not...
As I understand, the best way to run BLDC motors is to PWM only the High side switches and Low side ones are kept ON or OFF depending upon the commutation logic. Some even suggest using simple commutation of all 6 switches with speed control achieved by a single switch that controls the DC Link...
Everyone is providing valuable suggestions and I have been absent for a while now.
Well the good thing is that there is some news. Good or bad you guys decide...
I finally did the most basic testing which should have been done several days ago with a variac and a 300/5 CT (this was lying...
OK I realized yesterday that a ferrite core is pretty much useless as I kept thinking about the 20kHz carrier and forgot the main part, the 50Hz modulated signal, the very reason all of this is being done. (I do forget such obvious things sometimes:lol:)
OK so it's either a 100/5 CT or a 25VA...
First of all Thank You for this. I needed that as I was afraid people were going to call the idea unfeasible and silly. I just had it when I was actually standing in the middle of nowhere (sort of;-)) and knew my visit was a waste as I couldn't even measure the currents there. Even if we have...
While the multiple wire thing is OK, let us say I want to generate 100Amps RMS.
I like the short circuiting the secondary of a transformer and using it as a reverese CT thing but please help me with the math a bit.
Aim: To get 100A rms pure sinusoidal current through a conductor.
Ferrite core...
1℅ is OK. Basically this all started when one of our clamp meters showed 2A where a different one showed 5A. The frustrating thing was we had no idea which one to trust. I just wished I had a reference current to test which is correct and remembered that's exactly what I had made just a few...
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