flesher
Newbie level 6
In the second order control systerm
Hclosd(s)=Wn^2/(S^2+2EWnS+Wn^2), where E=damping factor.
Normally, the larger damping factor, the more stable for the systerm.
In third order type II PLL,
Hcolsed(s)=Wn^2(1+S/Wz)/(S^2+2EWnS+Wn^2),
Here: Natural Freq: Wn=sqrt[(Kvco*Icp)/(2*pi*Cbig*N)]
Damping Factor: E=(Rlpf/2)*sqrt[(Icp*Cbig*Kvco/2*pi*N)]
Phase margin: PM=arcten(Wc/Wz)-arcten(Wc/Wp)
However, damping factor here increases, the PM is not necessary to increase. It looks it has a maximum PM when damping factor increases.
So I am confused about these. hope someone to explain, thank you very much.
Hclosd(s)=Wn^2/(S^2+2EWnS+Wn^2), where E=damping factor.
Normally, the larger damping factor, the more stable for the systerm.
In third order type II PLL,
Hcolsed(s)=Wn^2(1+S/Wz)/(S^2+2EWnS+Wn^2),
Here: Natural Freq: Wn=sqrt[(Kvco*Icp)/(2*pi*Cbig*N)]
Damping Factor: E=(Rlpf/2)*sqrt[(Icp*Cbig*Kvco/2*pi*N)]
Phase margin: PM=arcten(Wc/Wz)-arcten(Wc/Wp)
However, damping factor here increases, the PM is not necessary to increase. It looks it has a maximum PM when damping factor increases.
So I am confused about these. hope someone to explain, thank you very much.