question about the stability of the system

[leebluer]

right half poles stablity

Hello,
I have some question about the stability of the system. The basic criterion about the stability of the system is whether it has the poles in right half-plane. Assume that the system has the pole P0(Unit: radians per second) in right half-plane. I think the step response may oscillate with the frequency at P0/(2*pi). But if the input signal is cos(w0*t) with the single frequecy at w0, could it oscillates only when w0 is equal to P0/(2*pi)?
I am confused about it. Could anyone make me clear?

Thanks

 

[Markie]

Hello,
I have some question about the stability of the system. The basic criterion about the stability of the system is whether it has the poles in right half-plane. Assume that the system has the pole P0(Unit: radians per second) in right half-plane. I think the step response may oscillate with the frequency at P0/(2*pi). But if the input signal is cos(w0*t) with the single frequecy at w0, could it oscillates only when w0 is equal to P0/(2*pi)?
I am confused about it. Could anyone make me clear?

Thanks

I don't quite understand your meaning.

I think that the stability is consideraly with the Phase Margin, that is, commonly it's the distance between polar P1 and P2. You say that if RHP is exist, then the circuit oscilate. Yes, it will oscillate eventually at its native frequence, nor related with the input signal.

May this can help you!

 

[nxing]

How the system can oscillate if it only have RHPs?
It will eventually wading down. Isn't it?

 

[Markie]

How the system can oscillate if it only have RHPs?
It will eventually wading down. Isn't it?

if a RHP is exist, to phase margin, is it equal to the zero phenomenon ?

 

[Tianlei]

The system must oscillate, even though you do not input any signal, just like oscillator. The noise of device and nonlinearity of the circuit will launch the oscillation.

The location of pole is the basic criteria of oscillation. The Nyquist critreria is derived from it.

Tianlei

 

[fehler]

Hello,
I have some question about the stability of the system. The basic criterion about the stability of the system is whether it has the poles in right half-plane. Assume that the system has the pole P0(Unit: radians per second) in right half-plane. I think the step response may oscillate with the frequency at P0/(2*pi). But if the input signal is cos(w0*t) with the single frequecy at w0, could it oscillates only when w0 is equal to P0/(2*pi)?
I am confused about it. Could anyone make me clear?

Thanks

In fact, I dont know how to get a system with RHP pole. But, for systems with
complex poles, there will be large ripple when settling. Then, you need to distinguish
between stationary and simutanous signal. For a step signal, any frequency is
present, then with complex pole, there will be ripple. But for a sine wave, only
one frequency is present, then for a LTI system, there will only be 1 frequency
out, or no ripple.

 

[segabird]

Hello,
I have some question about the stability of the system. The basic criterion about the stability of the system is whether it has the poles in right half-plane. Assume that the system has the pole P0(Unit: radians per second) in right half-plane. I think the step response may oscillate with the frequency at P0/(2*pi). But if the input signal is cos(w0*t) with the single frequecy at w0, could it oscillates only when w0 is equal to P0/(2*pi)?
I am confused about it. Could anyone make me clear?

Thanks

In fact, I dont know how to get a system with RHP pole. But, for systems with
complex poles, there will be large ripple when settling. Then, you need to distinguish
between stationary and simutanous signal. For a step signal, any frequency is
present, then with complex pole, there will be ripple. But for a sine wave, only
one frequency is present, then for a LTI system, there will only be 1 frequency
out, or no ripple.

But in naute, for a sine wave,there is some frequency noise which cause ripple.