CataM
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Hello everyone,
I need to design a DC to DC converter with the following specs:
Input voltage = 311 V (mains rectified)
Output Voltage ~ 62 V
Power = 1 kW
Switching frequency = to be decided
First of all, I can not use a transformer to step down the voltage beforehand because of size and money constraints.
Isolation for this stage is not necessary because the next stage of the application will have isolation.
The first converter that comes to mind is the Buck converter, however, I do not know why but seems like nobody uses a Buck converter for such a large voltage to drop to.
The only difficulty I see here is that I would need around 20% of duty cycle (assuming ideal Buck).
With Duty Cycle = 20 %, means that tON=0.2·T (0.2 times the period). Depending on the switching frequency I use, the "on time" could not be reached due to the influence of the turn on/turn off times of the transistors.
However, for switching freq = 20 kHz (seems reasonably well due to high power involvement and higher than audible range), tON=0.2*50 us= 10 us.
10 us of on time could not be influenced with nano second transistors.
My questions is: Why is not the Buck converter used for high voltage drop downs as the above one ? Am I overlooking something ?
Thank you for your time !
I need to design a DC to DC converter with the following specs:
Input voltage = 311 V (mains rectified)
Output Voltage ~ 62 V
Power = 1 kW
Switching frequency = to be decided
First of all, I can not use a transformer to step down the voltage beforehand because of size and money constraints.
Isolation for this stage is not necessary because the next stage of the application will have isolation.
The first converter that comes to mind is the Buck converter, however, I do not know why but seems like nobody uses a Buck converter for such a large voltage to drop to.
The only difficulty I see here is that I would need around 20% of duty cycle (assuming ideal Buck).
With Duty Cycle = 20 %, means that tON=0.2·T (0.2 times the period). Depending on the switching frequency I use, the "on time" could not be reached due to the influence of the turn on/turn off times of the transistors.
However, for switching freq = 20 kHz (seems reasonably well due to high power involvement and higher than audible range), tON=0.2*50 us= 10 us.
10 us of on time could not be influenced with nano second transistors.
My questions is: Why is not the Buck converter used for high voltage drop downs as the above one ? Am I overlooking something ?
Thank you for your time !