The P0922YU FPS400-24 can use the Lyapunov stability standard

This stability general’s power system has no input that can be applied to the Lyapunov stability criteria.

A linear system is called a bounded input bounded output (BIBO) stable if its output remains constant bounded for any bounded input.

Nonlinear systems accept input is input-state stability (ISS), which combines Lyapunov stability with a concept similar to BIBO stability.

For simplicity, the following descriptions focus on continuous time and discrete time linear systems.

Mathematically, this means that for a stable causal linear system the transfer function must have negative real values, that is, the real part of each pole must be less than zero. In fact, stability requires the existence of complex poles for the transfer function

In the open left half of the complex plane for continuous time, when the Laplace transform is used to obtain the transfer function.

Inside the unit circle for discrete time, when the z transform has been used.