In this design, Silicon Carbide (SiC) Schottky Diode is used as boost
diode.
As compared to standard ultra-fast silicon power diodes, silicon
Schottky devices offer improved performance because of their lower
forward drops and reduced forward and reverse recovery characteristics.
But their low breakdown voltages have limited their use to low-voltage
applications.
Silicon carbide overcomes these limitations with its high reverse
breakdown voltage and fast recovery.
Diode Reverse Voltage Rating
Diode reverse voltage is
similar to MOSFET blocking voltage. When diode is reverse biased, it
will have to block DC bus voltage which can rise up to 400 V maximum.
Leaving 50% room as safety factor, 600 V reverse blocking rating is
selected.
Diode Current Rating
When diode conducts
average and peak value of current passing through the diode can be
determined by
Equation 38.
Equation 39.
Power Dissipation in diode
There are two type of
losses in diode rectifier, for example, conduction loss and reverse
recovery loss. Major loss is contributed by forward voltage drop can be
given by