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help with PWM simulation in Matlab

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mess123

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I tried to model a boost DC-DC converter in matlab with PWM. Since the switching frequency is high (of the order of 100KHz), the matlab takes very long time to complete the simulation. I need to simulate the circuit for about 500 seconds.

Is there any method I can simulate it for long duration but in short time within matlab?

did you check the solver in configurations parameters?. i think you must prove another kind of solver, i mean , other algorithm.

500 sec for a DCDC simulation ??!! I'm not sure why is this, but i'm pretty sure u r doing sth wrong!! !st of all, u r sure ur circuit model works correctly?? I mean the results make sense??

Possible mistakes u might make includes: a) simulation algorithm: generally in such circuit, u should use discrete fixed step, like 5e-5, and ruler solver; b) u applied "PWM generator block" directly or u generate the PWM signal by ur own circuit? Buz ur own circuit is easy to mess up timing & phase things. c) which control u use, PID? Then check the gains u use.

mess123 said:
I tried to model a boost DC-DC converter in matlab with PWM. Since the switching frequency is high (of the order of 100KHz), the matlab takes very long time to complete the simulation. I need to simulate the circuit for about 500 seconds.

Is there any method I can simulate it for long duration but in short time within matlab?

upload your matlab model and i'll take a look at it. a lot of times its because you have a small time constant somewhere in your model.

or you can tone down your accuracy by forcing FIXED step time, rather than continuous solution solver.

there is also an acceleration option for simulation... but i never got that to work properly (always seems to run slower for me)

Mr.Cool

ya I tried other solver too in the matlab. I think the main problem is becuz of the switching frequency (100KHz). When I reduce it, it is ok.

Actually I want to give the input voltage of boost converter to the fuel cell output voltage. The fuel cell response time is very slow (~ 200 seconds). So, I want to look the output voltage of the boost converter until the fuel cell reaches steady state.

How can this problem be solved?

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