S
Scott Ronald
- Jan 1, 1970
- 0
I am looking at a multiple boost converter active power factor
correction circuit like below:
vin = 160*|sin(2pi*60*t)|
input filter is a LC lowpass, with cutoff somewhere between 60Hz and F_PWM
|-------------[input filter]-|---[inductor1]--|-[diode]-|---|----|
| | | | | |
| | [PWM1]--[fet1]-[gnd] | | [load]
[vin] | | | |
| |---[inductor2]--|-[diode]-| [cap] |
| | | | | |
| | [PWM2]--[fet2]-[gnd] | | |
| | | | |
| |---[inductor3]--|-[diode]-| | |
| | | | | |
| | [PWM3]--[fet3] | | |
| | | | | |
|----------------------------|----------------|---------|---|----|
|
[gnd]
My question is about the PWM controllers. My sampling rate is 100kHz so
I make my adjustments to the duty cycle at 100kHz.
should I run the PWMs separately and possibly have overlap so
in the 10us period:
PWM1 can be on from 0 to 5us
PWM2 can be on from 2.5us to 7.5us
PWM3 can be on from 5us to 10us
(each PWM has the same duty %)
or
A single multiplexed 300kHz PWM so that with no overlap
in the 10us period:
PWM1 can be on from 0 to 3.333us
PWM2 can be on from 3.333us to 6.666us
PWM3 can be on from 6.666us to 10us
(each PWM has the same duty%)
Scott
correction circuit like below:
vin = 160*|sin(2pi*60*t)|
input filter is a LC lowpass, with cutoff somewhere between 60Hz and F_PWM
|-------------[input filter]-|---[inductor1]--|-[diode]-|---|----|
| | | | | |
| | [PWM1]--[fet1]-[gnd] | | [load]
[vin] | | | |
| |---[inductor2]--|-[diode]-| [cap] |
| | | | | |
| | [PWM2]--[fet2]-[gnd] | | |
| | | | |
| |---[inductor3]--|-[diode]-| | |
| | | | | |
| | [PWM3]--[fet3] | | |
| | | | | |
|----------------------------|----------------|---------|---|----|
|
[gnd]
My question is about the PWM controllers. My sampling rate is 100kHz so
I make my adjustments to the duty cycle at 100kHz.
should I run the PWMs separately and possibly have overlap so
in the 10us period:
PWM1 can be on from 0 to 5us
PWM2 can be on from 2.5us to 7.5us
PWM3 can be on from 5us to 10us
(each PWM has the same duty %)
or
A single multiplexed 300kHz PWM so that with no overlap
in the 10us period:
PWM1 can be on from 0 to 3.333us
PWM2 can be on from 3.333us to 6.666us
PWM3 can be on from 6.666us to 10us
(each PWM has the same duty%)
Scott