请教各位关于boost converter 系统稳定的问题

hawkflior

有图吗？

confiope

上面有人说了
你在低频处是负增益
应该加上误差放大器
使得变成正增益。
然后看0DB时的
相位裕量

jasenlee

loop gain 该是正的才对，估计你建模有问题！

Mestc

要把放大器加上，增益都负了。
貌似在10E5频率上有双极点重合，要注意，可能会不稳定。

love_ic

估计是设置错误导致的，根本就没有Gain嘛！

[ 本帖最后由 love_ic 于 2009-8-27 17:45 编辑 ]

ytyash2

这肯定是稳定的，dc gain都是-40db

cicixu

's just the bode plot of the plant stage, seeing from the negative gain of the low frequency. Actually, you need to add the control circuit which will give enough gain at low frequency (for example, 80db or greater) and model the pwm block ( if you use such method, that means you need to model the switch and diode). After including the control circuit, the whole loop gain will be changed into positive, and you can measure the loop stablity. For system design, you need to get the model of the control IC(normally, can model it as OTA, and adding the compensation component).

xwcwc1234

大家帮忙分析.......