
AC-to-DC Three-Phase/Switch/Level PWM Boost Converter 12-11
It can be noticed, from Equation 12.13, that for v
in
> 0 and i
in
< 0, the source current i
in
always increases
whatever the state of Q is (note that the output voltage v
0
is always positive). Similarly, for v
in
< 0 and i
in
> 0, it
decreases continually. Hence, in both cases, the source current tends to have the same polarity as the source
voltage. Furthermore, the source current could not be modulated and, thus, has no tracking ability if it does
not have the same polarity as the source voltage. In other words, in order to ensure the current modulation
ability, the converter should opera ...