Abstract:
This paper presents a general method for
deciding the input filter capacitance of flyback switching acdc
converters with peak current-controlled mode. Firstly, a
simulation model for flyback ac-dc converter is obtained by
adding the rectifier and filter circuit to a flyback dc-dc
converter model developed by the authors. The simulation
results show that the processes of capacitor charging and
discharging are independent, their boundary is near the
maximal value of input voltage, and the part of flyback dcdc
converter can be seen as an approximately constant
power load. Secondly, an analytic model for deciding the
input power of flyback dc-dc converter with rated load and
different input dc voltages is presented. Furthermore, the
effect caused by the parasitical parameters in the electronic
parts is studied, and the corresponding analytical method
for deciding the input filter capacitance is given. The effect
on the capacitance caused by the control delay is analyzed
qualitatively.
