Hello everyone.
I'm simulating a two stage boost converter (cascaded) to step up 27Vcc to 380Vcc. I have achieved it with a duty cycle of about 72% for each MOSFET.
I have simulated the circuit triggering both MOSFET with the same PWM signal. And also with a 180° delay in the second MOSFET's PWM . Both triggering sequences work with only small differences in the transient...
Is there any "good design rule" about this triggering sequence? or I can just simply trigger them as I want?
Thank you in advance.
NOTE: Im running the simulation in Simulink.
Mauricio,
You should ensure that the first converter must not enter discontinuous mode of conduction, while the second one should preferably not enter discontinuous mode.
Other than those, things should be fine. For a duty cycle of 72%, each boost should be by a factor of roughly 1/(1-0.72), so that the the overall boost is by a factor of 12.76 or so. This takes 27V to about 344.38V.
-Sanjay
Hello,
There is no need of special attention with respect to cascaded switching. To get a better control independent control using PWM is preferred. To minimize the effect of EMI it is better to have phase delay between first and second stage. Hope you are conducting this experiment in open loop.
Regards,
Surya
It is not easy to get a concrete answer from so many papers and books, your help is appreciated!
Thank you.
Mauricio.
No need for special triggering sequence. Because the output of the first stage is filtered by the capacitor. that is why the second stage will get pure DC at its input. The 72% duty cycle is a little high for the boost converter, as in close loop it may exceed the calculated value, will effect the efficiency of the converter.
What is not mentioned in the question, is the power level. Assuming moderate power levels (
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